Shintaroh Kusunoki, Takako Fukuda, Saori Maeda, Chenjuan Yao, Takahiro Hasegawa, Tetsuya Akamatsu and Hiroshi Yoshimura : Relationships between feeding behaviors and emotions: An electroencephalogram (EEG) frequency analysis study, The Journal of Physiological Sciences, Vol.73, No.1, 2, 2023.
(要約)
Feeding behaviors may be easily affected by emotions, both being based on brain activity; however, the relationships between them have not been explicitly defined. In this study, we investigated how emotional environments modulate subjective feelings, brain activity, and feeding behaviors. Electroencephalogram (EEG) recordings were obtained from healthy participants in conditions of virtual comfortable space (CS) and uncomfortable space (UCS) while eating chocolate, and the times required for eating it were measured. We found that the more participants tended to feel comfortable under the CS, the more it took time to eat in the UCS. However, the EEG emergence patterns in the two virtual spaces varied across the individuals. Upon focusing on the theta and low-beta bands, the strength of the mental condition and eating times were found to be guided by these frequency bands. The results determined that the theta and low-beta bands are likely important and relevant waves for feeding behaviors under emotional circumstances, following alterations in mental conditions.
Takako Fukuda, Takashi Tominaga, Yoko Tominaga, Hiroyuki Kanayama, Nobuo Kato and Hiroshi Yoshimura : Alternative strategy for driving voltage-oscillator in neocortex of rats, Neuroscience Research, Vol.191, 28-37, 2022.
(要約)
Information integration in the brain requires functional connectivity between local neural networks. Here, we investigated the interregional coupling mechanism from the viewpoint of oscillations using optical recording methods. Low-frequency electrical stimulation of rat neocortical slices in a caffeine-containing medium induced oscillatory activity between the primary visual cortex (Oc1) and medial secondary visual cortex (Oc2M), in which the oscillation generator was located in the Oc2M and was triggered by a feedforward signal. During to-and-fro oscillatory activity, neural excitation was marked in layer II/III. When the upper layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the deep layer and switch on the oscillator in the Oc2M. When the lower layer was disrupted between Oc1 and Oc2M, feedforward signals could propagate through the upper layer and switch on the oscillator in the Oc2M. In the backward direction, neither the upper layer cut nor the lower layer cut disrupted the propagation of the oscillations. In all cases, the horizontal and vertical pathways were used as needed. Fluctuations in the oscillatory waveforms of the local field potential at the upper and lower layers in the Oc2M were reversed, suggesting that the oscillation originated between the two layers. Thus, the neocortex may work as a safety device for interregional communications in an alternative way to drive voltage oscillators in the neocortex.
Saori Maeda and Hiroshi Yoshimura : Enhancement of electroencephalogram activity in the theta-band range during unmatched olfactory-taste stimulation., The Journal of Physiological Sciences, Vol.69, No.4, 613-621, 2019.
(要約)
The aim of this study was to investigate how odor stimulation affects taste perception. Electroencephalogram (EEG) signals were measured from the frontal region of the head in normal, healthy subjects, and frequency analyses were performed. Each odor stimulation was delivered while the subject was tasting chocolate, using chocolate paste as the odorant for 'matched odor stimulation,' and garlic paste for 'unmatched odor stimulation.' Differences in EEG signals appeared between the matched and unmatched arms of the study. Comparison of the frequencies of EEGs captured under the condition of unmatched odor stimulation with those captured under the condition of matched odor stimulation showed that the occupancy rate of the theta-frequency band under the condition of unmatched odor stimulation was higher than that under the condition of matched odor stimulation. Interestingly, a negative correlation existed between the occupancy rate of the theta-frequency band and the subjective feeling of chocolate sweetness. The present findings suggest that when humans receive odors that do not match with the foods being consumed, subjective feelings are disturbed and theta-band brain activity is increased while the unmatched information is cross-checked.
Xiaoke Wang, Piaoyu Zhu, Shenya Xu, Yuting Liu, Yang Jin, Shali Yu, Haiyan Wei, Jinlong Li, Qinglin Zhang, Takahiro Hasegawa, Chenjuan Yao, Hiroshi Yoshimura, Qiyun Wu and Xinyuan Zhao : Antimony, a novel nerve poison, triggers neuronal autophagic death via reactive oxygen species-mediated inhibition of the protein kinase B/mammalian target of rapamycin pathway., The International Journal of Biochemistry & Cell Biology, Vol.114, 105561, 2019.
(要約)
Antimony (Sb), a naturally occurring metal present in air and drinking water, has been found in the human brain, and there is evidence of its toxic effects on neurobehavioral perturbations, suggesting that Sb is a potential nerve poison. Here, we provide the first study on the molecular mechanism underlying Sb-associated neurotoxicity. Mice exposed to antimony potassium tartrate hydrate showed significantly increased neuronal apoptosis. In vitro, Sb triggered apoptosis in PC12 cells in a dose-dependent manner. Mechanically, Sb triggered autophagy as indicated by increased expression of microtubule-associated protein 1 light chain 3-II (LC3-II) and accumulation of green fluorescent protein-tagged LC3 dots. Moreover, Sb enhanced autophagic flux and sequestosome 1 (p62) degradation. Subsequent analyses showed that Sb treatment decreased phosphorylation of protein kinase B (Akt) as well as the mammalian target of rapamycin (mTOR), while an Akt activator protected PC12 cells from autophagy. Moreover, the antioxidant N-acetylcysteine attenuated Sb-induced Akt/mTOR inhibition and decreased autophagy and apoptosis, with autophagy inhibition also playing a cytoprotective role. In vivo, mice treated with Sb showed higher expression of LC3-II and p62 in the brain, consistent with the in vitro results. In summary, Sb induced autophagic cell death through reactive oxygen species-mediated inhibition of the Akt/mTOR pathway.
Hiroshi Yoshimura, Sugai Tokio, Kato Nobuo, Tominaga Takashi, Tominaga Yoko, Takahiro Hasegawa, Chenjuan Yao and Tetsuya Akamatsu : Interplay between non-NMDA and NMDA receptor activation during oscillatory wave propagation: Analyses of caffeine-induced oscillations in the visual cortex of rats, Neural Networks, Vol.79, 141-149, 2016.
(要約)
Generation and propagation of oscillatory activities in cortical networks are important features of the brain. However, many issues related to oscillatory phenomena are unclear. We previously reported neocortical oscillation following caffeine treatment of rat brain slices. Input to the primary visual cortex (Oc1) generates N-methyl-d-aspartate (NMDA) receptor-dependent oscillations, and we proposed that the oscillatory signals originate in the secondary visual cortex (Oc2). Because non-NMDA and NMDA receptors cooperate in synaptic transmission, non-NMDA receptors may also play an important role in oscillatory activities. Here we investigated how non-NMDA receptor activities contribute to NMDA receptor-dependent oscillations by using optical recording methods. After induction of stable oscillations with caffeine application, blockade of NMDA receptors abolished the late stable oscillatory phase, but elicited 'hidden' non-NMDA receptor-dependent oscillation during the early depolarizing phase. An interesting finding is that the origin of the non-NMDA receptor-dependent oscillation moved from the Oc1, during the early phase, toward the origin of the NMDA receptor-dependent oscillation that is fixed in the Oc2. In addition, the frequency of the non-NMDA receptor-dependent oscillation was higher than that of the NMDA receptor-dependent oscillation. Thus, in one course of spatiotemporal oscillatory activities, the relative balance in receptor activities between non-NMDA and NMDA receptors gradually changes, and this may be due to the different kinetics of the two receptor types. These results suggest that interplay between the two receptor types in the areas of Oc1 and Oc2 may play an important role in oscillatory signal communication.
Hiroshi Yoshimura, 川邊 真道, 須貝 外喜夫, 加藤 伸郎, Takahiro Hasegawa, Chenjuan Yao and Tetsuya Akamatsu : Influences of oral impairment on neural oscilltion and wave propagation in the neocortex of rats, Neuroscience Research Suppl, Vol.Suppl, 2015.
7.
Hiroshi Yoshimura : Convergence of gustatory and olfactory information in the endopiriform nucleus of rats, Proceedings of the International Simposium on Neuroscience in Orofacial sensory-motor functions 2015, 14, 2015.
8.
Javkhlan Purevjav, Xu Guangfei, Chen Gang, Chenjuan Yao, Yuka Hiroshima, Hiroshi Yoshimura, Toshihiko Nagata and Kazuo Hosoi : Expression and LPS-Induced Elevation of Nod2 and Calprotectin in the Submandibular Gland of Wild-Type and TLR4-Knockout Male Mice, Journal of Research and Practice in Dentistry, Vol.2015, No.290259, 2015.
Mamichi Kawabe and Hiroshi Yoshimura : Influences of multiple tooth-loss on signal travel in the insular cortex of rats., European Journal of Oral Sciences, Vol.122, No.3, 175-180, 2014.
(要約)
The insular cortex (IC) processes various kinds of sensory and emotional information. Multiple tooth-loss induces impairment of oral sensory and motor functions, which might result in the up- or down-regulation of signal processing in the IC. In the present study, we investigated how multiple tooth-loss affects neural activities in the IC. Slices of the IC were prepared from control (untreated) rats and rats raised following the loss of their upper molar teeth, and optical recordings with voltage-sensitive dye were made. Electrical stimulation was delivered to the agranular IC (AIC). The velocity of optical signal from the AIC to the granular IC (GIC) decreased in multiple tooth-loss rats compared with control rats. Field potentials from the GIC were recorded. Onset times of evoked response at the GIC recorded from multiple tooth-loss rats were prolonged compared with those recorded from control rats, suggesting that signal velocity in multiple tooth-loss rats had decreased. A reduced signal velocity was accompanied by neuronal loss in the GIC, which was confirmed by counting the cell numbers on Nissl-stained sections. Thus, multiple tooth-loss may have influences on the GIC where signal processing speed decreases.
(キーワード)
Animals / Caffeine / Cell Count / Central Nervous System Stimulants / Cerebral Cortex / Electric Stimulation / Electrical Synapses / Evoked Potentials / Neural Pathways / Neurons / Rats / Rats, Wistar / Reaction Time / Somatosensory Cortex / Taste / Tooth / Tooth Loss / Voltage-Sensitive Dye Imaging
Gang Chen, Chenjuan Yao, Takahiro Hasegawa, Tetsuya Akamatsu, Hiroshi Yoshimura and Kazuo Hosoi : Effects of isoproterenol on aquaporin 5 levels in the parotid gland of mice in vivo., American Journal of Physiology, Endocrinology and Metabolism, Vol.306, No.1, E100-E108, 2014.
(要約)
In the membrane fraction of mouse parotid gland (PG), the protein level of aquaporin 5 (AQP5), a member of the water channel family, was increased by injection (ip) of isoproterenol (IPR), a β-adrenergic agonist, at 1 h, and stayed at high levels until 6 h; this change occurred simultaneously as amylase secretion. The AQP5 level then decreased and returned toward the original level at 12-48 h. After IPR injection, the AQP5 mRNA gradually increased and reached a maximum at 24 h. The facts suggest a rapid appearance of AQP5 at plasma membrane by IPR and subsequent degradation/metabolism by activation of proteolytic systems. Pretreatment of animals with two calpain inhibitors, N-Ac-Leu-Leu-methininal (ALLM) and calpeptin, as well as a protein synthesis inhibitor, cycloheximide (CHX), significantly suppressed the IPR-induced AQP5 degradation in the PG membrane fraction; such suppression was not observed by two proteasome inhibitors, MG132 and lactacystin, or the lysosome denaturant chloroquine, although most of these inhibitors increased AQP5 protein levels in unstimulated mice. The AQP5 protein was also degraded by μ-calpain in vitro. Furthermore, we demonstrated that μ-calpain was colocalized with AQP5 in the acinar cells by immunohistochemistry, and its activity in the PG was increased at 6 h after IPR injection. These results suggest that the calpain system was responsible for IPR-induced AQP5 degradation in the parotid gland and that such a system was coupled to the secretory-restoration cycle of amylase in the PG.
Hiroshi Yoshimura, Miho Hasumoto-Honjo, Tokio Sugai, Natsuki Segami and Nobuo Kato : Enhancement of oscillatory activity in the endopiriform nucleus of rats raised under abnormal oral conditions., Neuroscience Letters, Vol.561, 162-165, 2014.
(要約)
Endopiriform nucleus (EPN) is located deep to the piriform cortex, and has neural connections with not only neighboring sensory areas but also subcortical areas where emotional and nociceptive information is processed. Well-balanced oral condition might play an important role in stability of brain activities. When the oral condition is impaired, several areas in the brain might be affected. In the present study, we investigated whether abnormal conditions of oral region influence neural activities in the EPN. Orthodontic appliance that generates continuous force and chronic pain-related stress was fixed to maxillary incisors of rats, and raised. Field potential recordings were made from the EPN of brain slices. We previously reported that the EPN has an ability to generate membrane potential oscillation. In the present study, we have applied the same methods to assess activities of neuron clusters in the EPN. In the case of normal rats, stable field potential oscillations were induced in the EPN by application of low-frequency electrical stimulation under the medium with caffeine. In the case of rats with the orthodontic appliance, stable field potential oscillations were also induced, but both duration of oscillatory activities and wavelet number were increased. The enhanced oscillations were depressed by blockade of NMDA receptors. Thus, impairment of oral health under application of continuous orthodontic force and chronic pain-related stress enhanced neural activities in the EPN, in which up-regulation of NMDA receptors may be concerned. These findings suggest that the EPN might be involved in information processing with regard to abnormal conditions of oral region.
Hiroshi Yoshimura, Tokio Sugai, Takahiro Hasegawa, Chenjuan Yao, Tetsuya Akamatsu and Nobuo Kato : Age-dependent emergence of caffeine-assisted voltage oscillations in the endopiriform nucleus of rats., Neuroscience Research, Vol.76, No.1-2, 16-21, 2013.
(要約)
The gustatory insular cortex (IC) is connected with not only the somatosensory cortex, but also the endopiriform nucleus (EPN). We have previously revealed that low-frequency electrical stimulation to the IC can elicit membrane potential oscillations at a frequency of 8-10 Hz in the somatosensory cortex of rat brain slices under bath-application of caffeine. Using the same procedure, we investigated whether the EPN has the ability to generate oscillations, and whether such oscillations emerge age-dependently. Electrical stimulations were delivered to the IC, and field potentials were recorded from the EPN. In the case of slices made from mature rats, stable field potential oscillations at 8-10 Hz were induced in the EPN after repetitive stimulations. Optical recordings revealed that signals traveled from the IC to the EPN by way of the claustrum. Generation of oscillations was N-methyl-d-aspartate (NMDA) receptor activity-dependent, since oscillatory phases disappeared following application of NMDA receptor antagonist. In slices from immature rats, however, oscillations were not induced. IC stimulation can thus age-dependently elicit membrane potential oscillations in the EPN, and the EPN oscillations were NMDA receptor activity-dependent. These findings suggest that developmental changes in properties of the EPN might contribute to development of information integration, including gustatory information.
(キーワード)
加齢 (aging) / Animals / Caffeine / Central Nervous System Stimulants / Cerebral Cortex / Electric Stimulation / Membrane Potentials / Organ Culture Techniques / Rats / Rats, Wistar
T Sugai, R Yamamoto, Hiroshi Yoshimura and N Kato : Multimodal Cross-Talk of Olfactory and Gustatory Information in the Endopiriform Nucleus in Rats., Chemical Senses, Vol.37, No.8, 681-688, 2012.
(要約)
The endopiriform nucleus (EPN) is a large group of multipolar cells located in the depth of the piriform cortex (PC). Although many studies have suggested that the EPN plays a role in temporal lobe epilepsy, the normal function of the EPN remains to be elucidated. By using optical imaging of coronal brain slice preparations with voltage-sensitive dye, we found signal propagation from the PC or gustatory cortex (GC) to the EPN in normal medium. In our previous research, we failed to elicit a reliable signal reproducibly in the EPN by single stimulation either to the PC or GC. In our current research, we found that a double-pulse stimulation to either the PC or GC (interpulse interval: 20-100 ms) induced robust signal propagation to the EPN through excitation in the agranular division of the insular cortex (AI), with further extension to the claustrum. Finally, double site paired-pulse stimulation to the PC and GC also evoked excitation in the AI, claustrum, and EPN.These results suggest that the EPN has dual roles: 1) further processing of modality-specific olfactory and gustatory information from the PC and GC, respectively and 2) synergistic integration of PC-derived olfactory information and GC-derived gustatory information.
Hiroshi Yoshimura, Miho Honjo, Tokio Sugai, Mamichi Kawabe, Keiseki Kaneyama, Natsuki Segami and Nobuo Kato : Influences of audio-visual environments on feelings of deliciousness during having sweet foods: an electroencephalogram frequency analysis study., Nutritional Neuroscience, Vol.14, No.5, 210-215, 2011.
(要約)
Feelings of deliciousness during having foods are mainly produced by perceptions of sensory information extracted from foods themselves, such as taste and olfaction. However, environmental factors might modify the feeling of deliciousness. In the present study, we investigated how the condition of audio-visual environments affects the feeling of deliciousness during having sweet foods. Electroencephalograms (EEGs) were recorded from the frontal region of the scalp of healthy participants under virtual scenes of tearoom and construction work, respectively. The participants were asked to rate deliciousness after the recordings. Frequency analyses were performed from the EEGs. During having the foods, occupancy rates of beta frequency band between tearoom scenes and construction work scenes were markedly different, but not in other frequency bands. During having no food, in contrast, there was no difference of occupancy rates in respective frequency bands between the two different scenes. With regard to deliciousness during having sweet foods, all participants rated high scores under the scenes of tearoom than those under the scenes of construction work. Interestingly, there is a positive correlation between occupancy rates of beta frequency band and scores of deliciousness. These findings suggest that comfortable audio-visual environments play an important role in increasing the feeling of deliciousness during having sweet foods, in which beta frequency rhythms may be concerned with producing comprehensive feelings of deliciousness.
Hiroshi Yoshimura, Miho Honjo, Tokio Sugai, Keiseki Kaneyama, Natsuki Segami and Nobuo Kato : Correlation between stimulation strength and onset time of signal traveling within the neocortical neural circuits under caffeine application., Neuroscience Research, Vol.70, No.4, 370-375, 2011.
(要約)
In general, strength of input to neocortical neural circuits affects the amplitude of postsynaptic potentials (PSPs), thereby modulating the way signals are transmitted within the circuits. Caffeine is one of the pharmacological agents able to modulate synaptic activities. The present study investigated how strength of input affects signal propagation in neocortical circuits under the application of caffeine. Spatio-temporal neural activities were observed from visual cortical slices of rats using optical recording methods with voltage-sensitive dye. Electrical stimulations were applied to white matter in the primary visual cortex with bath-application of caffeine. When the strength of stimulation was 0.3mA, signals propagated from the site of stimulation in the primary visual cortex toward the secondary visual cortex along vertical and horizontal pathways. When stimulation strength was reduced from 0.3mA to 0.07mA, start of signal propagation was delayed about 25ms without affecting field PSP amplitude or the manner of signal propagation. Conversely, co-application of caffeine and d-2-amino-5-phosphonovaleric acid (d-AP5) did not induce delays in signal start. These findings suggest that conversion of neural code from amplitude code to temporal code is inducible at the level of neocortical circuits in an N-methyl-d-aspartate (NMDA) receptor activity-dependent manner.
(キーワード)
Animals / Caffeine / Electric Stimulation / Membrane Potentials / Neocortex / Nerve Net / Rats / Rats, Wistar / シグナル伝達 (signal transduction) / Time Factors / Visual Cortex
Keiseki Kaneyama, Natsuki Segami, Rie Nishiura and Hiroshi Yoshimura : Internal derangement of the temporomandibular joint with mouth-closing disturbance caused by a thickness of retrodiscal tissue: a case report., Journal of Oral and Maxillofacial Surgery, Vol.69, No.4, 1052-1055, 2011.
(キーワード)
Arthroscopy / Debridement / Dislocations / Female / Fibrosis / Humans / Hyperplasia / Magnetic Resonance Imaging / Malocclusion / Middle Aged / Open Bite / Range of Motion, Articular / Temporomandibular Joint Disc / Temporomandibular Joint Disorders
Hiroshi Yoshimura, Shigeto Morimoto, Masashi Okuro, Natsuki Segami and Nobuo Kato : Evaluations of dementia by EEG frequency analysis and psychological examination., The Journal of Physiological Sciences, Vol.60, No.5, 383-388, 2010.
(要約)
In order to evaluate the stage of dementia, we focused attention on EEG rhythms and Hasegawa-dementia-rating scale (HDS-R). Frontal EEGs were recorded from dementia patients and normal controls during music and photo-image stimulations, and frequency analysis was performed. In the controls, profiles of rhythm pattern during music stimulation seemed to be markedly different from those during photo-image stimulation. In contrast, in dementia patients, it was difficult to find those differences. Interestingly, as HDS-R decreases, the variability of rhythm patterns also decreases. These results suggest that a decrease in cognitive function might be related to a decrease in the ability to generate various cortical rhythm patterns.
Keiseki Kaneyama, Natsuki Segami, Hiroshi Yoshimura, Miho Honjo and Noboru Demura : Increased levels of soluble cytokine receptors in the synovial fluid of temporomandibular joint disorders in relation to joint effusion on magnetic resonance images., Journal of Oral and Maxillofacial Surgery, Vol.68, No.5, 1088-1093, 2010.
(要約)
Increased levels of cytokine receptors are likely to influence the expression of JE and may play important roles in the pathogenesis of TMD. These results also suggest that JE may reflect synovial inflammation of the TMJ.
(キーワード)
Adult / Dislocations / Humans / Interleukin 1 Receptor Antagonist Protein / 磁気共鳴映像法 (magnetic resonance imaging) / Mandibular Condyle / Osteoarthritis / Osteophyte / Pain Measurement / Paracentesis / Proteins / Range of Motion, Articular / 炎症性サイトカイン受容体の情報伝達 (Signal transduction of proinflammatory cytokine receptors) / Receptors, Interleukin-1 Type II / Receptors, Interleukin-6 / Receptors, Tumor Necrosis Factor, Type I / Receptors, Tumor Necrosis Factor, Type II / Synovial Fluid / Synovitis / Temporomandibular Joint Disc / Temporomandibular Joint Disorders
Hiroshi Yoshimura, Tokio Sugai, Miho Honjo, Keiseki Kaneyama, Natsuki Segami and Nobuo Kato : Application of caffeine reveals input frequency-dependent determination of signal-traveling routes between primary and secondary visual cortices in rats., Neuroscience Research, Vol.66, No.1, 30-36, 2009.
(要約)
Upon entering the neocortex, neural signals are required to select which neocortical circuits to propagate through. The present study focused attention on use-dependent selection of signal-traveling routes. Rat brain slices including primary visual cortex (Oc1) and the medial part of the secondary visual cortex (Oc2M) were prepared. Electrical stimulation was delivered to white matter in Oc1 and spatiotemporal aspects of traveling signals were observed using optical recording methods under caffeine application. With an interstimulus interval (ISI) of 4-8s, signals traveled horizontally along deep layers from Oc1 to Oc2M, climbed within Oc2M, then returned along layer II/III from Oc2M to Oc1. Conversely, with an ISI of 40-64s, signals climbed within Oc1 and traveled horizontally along layer II/III from Oc1 to Oc2M in parallel with signals traveling along deep layers. Pharmacological experiments with antagonists for ionotropic glutamate receptors revealed that signal-traveling routes under higher-frequency stimulation were N-methyl-d-aspartate (NMDA) receptor activity-dependent, while those at the lower-frequency were non-NMDA receptor activity-dependent. These results suggest that neural circuits between Oc1 and Oc2M possess an input frequency-dependent gating system, in which signal-traveling routes might be affected by the relative balance of receptor activities between NMDA and non-NMDA receptors.
(キーワード)
2-Amino-5-phosphonovalerate / 6-Cyano-7-nitroquinoxaline-2,3-dione / Animals / Animals, Newborn / Biophysics / Brain Mapping / Caffeine / Central Nervous System Stimulants / Electric Stimulation / Evoked Potentials / Excitatory Amino Acid Antagonists / Iontophoresis / Nerve Net / Rats / Rats, Wistar / Time Factors / Visual Cortex / Visual Pathways
Hiroshi Yoshimura, Makoto Honjo, Yuichi Mashiyama, Keiseki Kaneyama, Natsuki Segami, Jun Sato, Tokio Sugai, Nobuo Kato and Norihiko Onoda : Multiple tooth-losses during development suppress age-dependent emergence of oscillatory neural activities in the oral somatosensory cortex., Brain Research, Vol.1224, 37-42, 2008.
(要約)
Tooth and tooth-related organs play important roles in not only mastication, but also sensory perception in the oral region. In general, sensory neural inputs during the developmental period are required for the maturation of functions in the sensory cortex. However, whether maturations of oral somatosensory cortex (OSC) require certain levels of sensory input from oral regions has been unclear. The present study investigated the influence of multiple tooth-losses during the developmental period on age-dependent emergence of rhythmic activities of population neurons in the OSC. Low-frequency electrical stimulation was delivered to layer IV and field potentials were recorded from layer II/III in the OSC of rat brain slices. In control rats, N-methyl-d-aspartate (NMDA) receptor-dependent oscillation at 8-10 Hz appeared during postnatal weeks 2-3. In rats with extraction of multiple teeth at 17-18 days old, oscillation did not appear even at maturity, whereas in rats with multiple teeth extracted at 37-38 days old, oscillation appearances were maintained in maturity. Thus, emergence of oscillation in the OSC was suppressed by multiple tooth-losses during postnatal 2-3 weeks. These results suggest that sufficient neural inputs from the teeth and tooth-related organs during developmental periods are essential for maturation of neural functions in the OSC.
Hiroshi Yoshimura, Yuichi Mashiyama, Keiseki Kaneyama, Toshikazu Nagao and Natsuki Segami : Opening of shortcut circuits between visual and retrosplenial granular cortices of rats., NeuroReport, Vol.18, No.13, 1315-1318, 2007.
(要約)
Traveling neural signals may try to find suitable paths of propagation in cortical circuits. We examined the behavior of electrically evoked signals from primary visual cortex (Oc1) to granular retrosplenial cortex (RSG) in rat brain slices under caffeine application. With continued electrical stimulation, evoked signals propagated from Oc1 to RSG along the upper layer of the secondary visual cortex (Oc2) and agranular retrosplenial cortex (RSA), but on further continuation of stimulation, a new shortcut pathway along the deep layer between Oc2 and RSG was opened. Circuitry changes reduced the signal traveling time by about 40 ms. Cortical neural circuits between Oc1 and RSG may thus have the ability to open a shortcut circuit in a use-dependent manner.
Keiseki Kaneyama, Natsuki Segami, Jun Sato, Hiroshi Yoshimura and Rie Nishiura : Expression of receptor activator of nuclear factor-kappaB ligand in synovial tissue: comparison with degradation of articular cartilage in temporomandibular joint disorders., Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, Vol.104, No.2, e12-7, 2007.
(要約)
These observations indicated that the cellular source of osteoclastic differentiation exists in TMJ with ID and may provide insight into the mechanism of osteoclast differentiation.
Keiseki Kaneyama, Natsuki Segami, Jun Sato, Kazuma Fujimura, Toshikazu Nagao and Hiroshi Yoshimura : Prognostic factors in arthrocentesis of the temporomandibular joint: Comparison of bradykinin, leukotriene B4, prostaglandin E2, and substance P level in synovial fluid between successful and unsuccessful cases., Journal of Oral and Maxillofacial Surgery, Vol.65, No.2, 242-247, 2007.
(要約)
Increased levels of BK and LTB4 in the synovial fluid of patients with TMDs may indicate that arthrocentesis is less likely to be a successful treatment.
Jun Sato, Natsuki Segami, Yoshino Yoshitake, Keiseki Kaneyama, Hiroshi Yoshimura, Kazuma Fujimura and Yoshimasa Kitagawa : Specific expression of substance P in synovial tissues of patients with symptomatic, non-reducing internal derangement of the temporomandibular joint: comparison with clinical findings., The British Journal of Oral & Maxillofacial Surgery, Vol.45, No.5, 372-377, 2006.
(要約)
Our aim was to find out the extent of expression of substance P in synovial tissue from the human temporomandibular joints (TMJ) with symptomatic, non-reducing internal derangement, and to investigate the relationship between substance P and clinical findings. Fifty-four joints in 54 patients were examined immunohistochemically. Specimens of synovial tissue from 10 joints in 8 subjects with habitual dislocation of the TMJ with no pain were examined as controls. Cells that stained for substance P were found mainly among the endothelial cells in the blood vessels beneath the lining cells in synovial tissues from 47 of the 54 joints (87%) with internal derangement and from 5 of the 10 control joints. The extent score of cells that stained for substance P in joints with internal derangement was significantly higher than that in controls (p=0.02). The extent score of these cells did not correlate with pain in the joint or the degree of synovitis. These results suggest that substance P may have some roles in both the physiological and pathological conditions in patients with symptomatic internal derangement of the TMJ.
Tokio Sugai, Hiroshi Yoshimura, Nobuo Kato and Norihiko Onoda : Component-dependent urine responses in the rat accessory olfactory bulb., NeuroReport, Vol.17, No.16, 1663-1667, 2006.
(要約)
To investigate how pheromonal information is processed in the rat accessory olfactory bulb, we optically imaged intrinsic signals to obtain high-resolution maps of activation induced by urinary stimulation. Application of volatile components in male urine mainly induced activation in the anterior accessory olfactory bulb, irrespective of the sex, whereas volatile female urine elicited activation not only in the anterior but also to some extent in the caudal part of the posterior accessory olfactory bulb of male, but not female, rats. Nonvolatile components of both male and female urine induced activation mainly in the rostral part of the posterior and to a lesser extent in the anterior accessory olfactory bulb, irrespective of the sex. These results indicate that volatile and nonvolatile urinary components activate the anterior and posterior subdivisions of the accessory olfactory bulb, respectively.
(キーワード)
Animals / Female / Male / Olfactory Bulb / Optics and Photonics / Pheromones / Rats / Rats, Wistar / Sex Factors / Urine
Hiroshi Yoshimura, Makoto Honjo, Natsuki Segami, Keiseki Kaneyama, Tokio Sugai, Yuichi Mashiyama and Norihiko Onoda : Cyclic AMP-dependent attenuation of oscillatory-activity-induced intercortical strengthening of horizontal pathways between insular and parietal cortices., Brain Research, Vol.1069, No.1, 86-95, 2006.
(要約)
Cyclic AMP (cAMP) is a key intracellular second messenger, and the intracellular cAMP signaling pathway acts to modulate various brain functions. We have previously reported that low-frequency insular cortex stimulation in rat brain slices switches on a voltage oscillator in the parietal cortex that delivers signals horizontally back and forth under caffeine application. The oscillatory activities are N-methyl-D-aspartate (NMDA) receptor-dependent, and the role of oscillation is to strengthen functional intercortical connections. The present study investigated actions of the cAMP signaling pathway on caffeine-induced strengthening of intercortical connections and tried to confirm the role of oscillation on intercortical strengthening by focusing on the cAMP pathway. After induction of parietal oscillation by insular cortex stimulation in caffeine-containing medium, application of membrane-permeable cAMP analog, bromo-cAMP, diminished oscillatory signal delivery from the parietal cortex, but initial insulo-parietal signal propagation remained strong. When oscillatory activities were reduced with co-application of caffeine and bromo-cAMP from the beginning, initial insulo-parietal propagation was established, but amplitudes of propagating wavelets and propagating velocity were reduced. Thus, cAMP-dependent diminution of caffeine-induced NMDA-receptor-dependent oscillatory signal delivery causes attenuation of intercortical strengthening of horizontal pathways between insular and parietal cortices. This finding suggests that the intracellular cAMP signaling pathway has the ability to regulate extracellular communications at the network level, and also that full expression of strengthened intercortical signal communication requires sufficient NMDA-receptor-dependent oscillatory neural activities.
Jun Sato, Natsuki Segami, Yoshino Yoshitake, Keiseki Kaneyama, Atsuko Abe, Hiroshi Yoshimura and Kazuma Fujimura : Expression of capsaicin receptor TRPV-1 in synovial tissues of patients with symptomatic internal derangement of the temporomandibular joint and joint pain., Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, Vol.100, No.6, 674-681, 2005.
(要約)
TRPV-1 was detected in the region of the posterior disk attachment of synovial tissues from the TMJ in patients with internal derangement and controls. TRPV-1 may play a role in maintenance of the physiologic condition of the TMJ.
Hiroshi Yoshimura, Tokio Sugai, Makoto Honjo, Natsuki Segami and Norihiko Onoda : NMDA receptor-dependent oscillatory signal outputs from the retrosplenial cortex triggered by a non-NMDA receptor-dependent signal input from the visual cortex., Brain Research, Vol.1045, No.1-2, 12-21, 2005.
(要約)
The retrosplenial cortex is located at a critical juncture between the visual cortex and hippocampal formation. Functions of the retrosplenial cortex at the local circuit level, however, remain unclear. Herein, we show how signals traveling from the visual cortex behave in local circuits of the retrosplenial cortex, using optical recording methods and application of caffeine to rat brain slices. Electrical signals evoked in the primary visual cortex penetrated into the deep layer of the retrosplenial granular a cortex (RSGa) and propagated further toward postsubiculum and upper layer. Non-N-methyl-D-aspartate (NMDA) receptor-dependent initial traveling signal from the visual cortex triggered NMDA receptor-dependent neural oscillation in the RSGa. Oscillatory signals originated from the local area in the deep layer of the RSGa, and the signal spread back and forth toward the visual cortex and postsubiculum, in addition to spreading toward the upper layer. From the perspective of the RSGa, extrinsic signal inputs from the visual cortex switched on neural oscillators in the RSGa that deliver NMDA receptor-dependent intrinsic signal outputs. Opening and strengthening of non-NMDA receptor-dependent input pathways from the visual cortex required NMDA receptor-dependent oscillatory neural activities. These input and output relationships indicate that the retrosplenial cortex may represent an important relay station between the visual cortex and hippocampal formation.
Hiroshi Yoshimura, Tokio Sugai, Natsuki Segami and Norihiko Onoda : Strengthening of non-NMDA receptor-dependent horizontal pathways between primary and lateral secondary visual cortices after NMDA receptor-dependent oscillatory neural activities., Brain Research, Vol.1036, No.1-2, 60-69, 2005.
(要約)
Emergence of oscillatory signal flows between the primary visual cortex (Oc1) and medial secondary visual cortex (Oc2M) was previously dynamically demonstrated in rat brain slices by us. Applying caffeine, a neural modulator, to the slices and using optical recording methods revealed this facilitation along horizontal intrinsic pathways in which initial forward propagation from Oc1 to Oc2M was dependent on both N-methyl-D-aspartate receptors (NMDARs) and non-NMDARs. Conversely, oscillatory backward propagation from Oc2M to Oc1 was entirely dependent on NMDARs. The present study examined: (1) whether the signal behavior between Oc1 and lateral secondary visual cortex (Oc2L) is based on the same mechanism with that between Oc1 and Oc2M; and (2) how non-NMDAR and NMDAR activities underlie opening of horizontal corticocortical pathways between Oc1 and Oc2. Under NMDAR blockade, signals elicited in the Oc1 either could not or only weakly penetrated the Oc2L, even in caffeine-containing medium. In contrast, once forward propagation from Oc1 to Oc2L and oscillatory backward propagation from Oc2L to Oc1 was established in caffeine-containing medium, signals elicited in Oc1 could strongly penetrate the Oc2 even during blockade of NMDA activities, when forward penetrating components were dependent on non-NMDARs. These findings suggest that: (1) signal behavior and its mechanism between Oc1and Oc2L are the same with those between Oc1 and Oc2M; and (2) NMDAR activation results in non-NMDAR activity, resulting in opening and strengthening of intrinsic signal pathways between Oc1 and Oc2. NMDAR-dependent forward and backward propagation might be involved in cortical reorganization of the visual cortex.
T Sugai, T Miyazawa, M Fukuda, Hiroshi Yoshimura and N Onoda : Odor-concentration coding in the guinea-pig piriform cortex., Neuroscience, Vol.130, No.3, 769-781, 2005.
(要約)
By optical imaging of intrinsic signals, we demonstrated a possible code for odor concentration in the anterior piriform cortex of the guinea-pig. Odor-induced cortical activation, which primarily originated in layer II, appeared in a narrow band beneath the rhinal sulcus over the lateral olfactory tract, corresponding to the dorsal part of the anterior piriform cortex. Lower concentrations activated the rostral region of the band, whereas higher ones generated caudally spreading activation, and the site at which neural activation reached its maximum extent depended upon odor concentration. Different odors with low concentrations generated distinct but somewhat overlapping patterns in the rostral region of the band; the limited extent of cortical activity may be one focal domain for each odor. It was hard to judge, however, that odor-specific domains appeared in the anterior piriform cortex, because the strong stimuli induced largely overlapping patterns. Furthermore, the total area activated increased in proportion to concentrations raised to a power of 0.5-0.9. Importantly, these imaging results were confirmed with unit recordings which indicated a rostro-caudal gradient in odor-sensitivity among cortical neurons. Our results suggest that the dorsal part of the anterior piriform cortex may be associated with odor concentration. Therefore, in addition to recruitment of more olfactory sensory cells and glomeruli in response to stronger stimuli, a rostro-caudal gradient in axonal projections from mitral/tufted cells and/or in association fibers may play an important role in odor-concentration coding in the anterior piriform cortex.
T Sugai, T Miyazawa, Hiroshi Yoshimura and N Onoda : Developmental changes in oscillatory and slow responses of the rat accessory olfactory bulb., Neuroscience, Vol.134, No.2, 605-616, 2005.
(要約)
Field potential, patch-clamp and optical recordings were performed in accessory olfactory bulb slices of postnatal rats following single electrical stimulation of the vomeronasal nerve layer. On the basis of differences in the components of the field potential, postnatal days were divided into three periods: immature (until postnatal day 11), transitional (postnatal days P12-17) and mature periods (after postnatal day 18). During the immature period, vomeronasal nerve layer stimulation provoked a characteristic damped oscillatory field potential, and the field potential recorded in the glomerular layer consisted of a compound action potential followed by several periodic negative peaks superimposed on slow components. Reduction in [Mg2+] enhanced slow components but did not affect oscillation, whereas an NMDA receptor antagonist, D-2-amino-5-phosphonovalerate, depressed slow components but did not affect the oscillation. During the mature period, slow components and the periodic waves (oscillation) disappeared. The time course of the field potential was similar to that in adults, suggesting that the accessory olfactory bulb reached electrophysiologically maturity at postnatal day 18. A non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione, inhibited vomeronasal nerve layer-induced responses, while D-2-amino-5-phosphonovalerate had no effect, suggesting that NMDA and non-NMDA receptors are active in immature tissues, whereas non-NMDA receptors predominated in mature tissue. Results from whole-cell patch recordings in mitral and granule cells yielded results consistent with those from field potential and optical recordings. Further, a gradual decrease in number and frequency of oscillating waves was observed until postnatal day 17. Analyses of the depth profile of field potentials and current source density in immature tissue suggested that the oscillation and slow components originated in the glomerular layer but not in the external plexiform/mitral cell layer. Further, a new type of oscillation, which was independent of the reciprocal dendrodendritic synapses between mitral and granule cells, was detected. These data indicate that the lack of oscillatory suppression by immature NMDA receptors may play a critical role in the dynamic alteration of bulbar conditions.
Jun Sato, Natsuki Segami, Keiseki Kaneyama, Hiroshi Yoshimura, Kazuma Fujimura and Yoshino Yoshitake : Relationship of calcitonin gene-related peptide in synovial tissues and temporomandibular joint pain in humans., Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, Vol.98, No.5, 533-540, 2004.
(要約)
These results suggest that the expression of CGRP is increased in the synovial tissues from patients with internal derangement, and that CGRP seems to play an important role in the mechanism of pain production in patients with symptomatic internal derangement.
Hiroshi Yoshimura, Nobuo Kato, Tokio Sugai, Makoto Honjo, Jun Sato, Natsuki Segami and Norihiko Onoda : To-and-fro optical voltage signal propagation between the insular gustatory and parietal oral somatosensory areas in rat cortex slices., Brain Research, Vol.1015, No.1-2, 114-121, 2004.
(要約)
Taste perception depends not only on special taste information processed in the insular cortex, but also on oral somesthetic processing in the parietal cortex. Many insular cortex neurons show multimodal responsiveness. Such multimodality may be enabled by signal exchange between these two cortices. By using the protocol that we have developed, a synchronized population oscillation of synaptic potentials was induced in the parietal cortex by stimulation to the insular cortex in rat neocortex slices. The spatiotemporal pattern of propagation of this oscillation was studied by recording voltage-sensitive optical signals and field potentials. The first wavelet of the oscillation was propagated from the insular stimulation site to the parietal cortex. However, the second and later wavelets propagated back from the parietal cortex to the insular cortex. The oscillation was detected in the insular cortex as well, but was actually generated in the parietal cortex. Thus, the initial peak of optical signal, sent from the insular to parietal cortex, served to generate oscillatory responses in the parietal cortex, which propagated back to the insular cortex wave-by-wave. We propose that this to-and-fro propagation may be an artificially exaggerated demonstration of an intrinsic mechanism relevant to signal exchange between the parietal and insular cortices.
Keiseki Kaneyama, Natsuki Segami, Jun Sato, Masaaki Nishimura and Hiroshi Yoshimura : Interleukin-6 family of cytokines as biochemical markers of osseous changes in the temporomandibular joint disorders., The British Journal of Oral & Maxillofacial Surgery, Vol.42, No.3, 246-250, 2004.
(要約)
The aim of this study was to find out whether there was a correlationship between the concentrations of interleukin-6 (IL-6), IL-11, and IL-17 in synovial fluid and osseous changes in the condyle. The synovial fluid was obtained from 61 patients with temporomandibular joint disorders (TMD) and seven healthy volunteers (controls). The concentrations of IL-6, IL-11, and IL-17 were measured by enzyme-linked immunosorbent assay. IL-6 was detected in 43 of 59 (73%), IL-11 in 23 of 52 (44%) and IL-17 in 14 of 51 (27%) samples of synovial fluid. The concentrations of IL-6 and IL-11 in the joints with osseous changes in the condyle were significantly higher than in the joints without osseous changes (P < 0.05) and also higher than in the joints of the control group (P < 0.05). In addition, there was a correlation of concentrations between IL-6 and IL-11 (P < 0.05). These results suggest that IL-6 and IL-11 may participate in the pathogenesis of TMD and induce osseous changes in the condyle.
Keiseki Kaneyama, Natsuki Segami, Masaaki Nishimura, Jun Sato, Kazuma Fujimura and Hiroshi Yoshimura : The ideal lavage volume for removing bradykinin, interleukin-6, and protein from the temporomandibular joint by arthrocentesis., Journal of Oral and Maxillofacial Surgery, Vol.62, No.6, 657-661, 2004.
(要約)
Arthrocentesis is effective for washing out bradykinin, interleukin-6, and protein from the TMJ, and the ideal lavage volume of perfusate for arthrocentesis is between 300 and 400 mL.
Hiroshi Yoshimura, Nobuo Kato, Makoto Honjo, Tokio Sugai, Natsuki Segami and Norihiko Onoda : Age-dependent emergence of a parieto-insular corticocortical signal flow in developing rats., Brain Research. Developmental Brain Research, Vol.149, No.1, 45-51, 2004.
(要約)
By using the procedure that we developed for inducing population oscillation, it was previously demonstrated that insular cortex stimulation can evoke insulo-parietal field potential propagation and synchronized population oscillation in the parietal cortex in slices obtained from mature rats (27-35 days old). By using the same procedure, we have now studied the reciprocal parieto-insular projection. Parietal cortex stimulation elicited synchronized population oscillation in the parietal--but not insular--cortex in mature tissues. In the insular cortex, the initial wavelet of the oscillation generated by parietal cortex stimulation propagated, but the entire oscillation did not. A prior induction--but not simultaneous occurrence--of oscillation in the parietal cortex sufficed to have this initial wavelet propagate. In immature tissue (9-10 days old), both the parietal cortex oscillation and the parieto-insular propagation were induced only with low [Mg2+]o. This age dependence is exactly the same as we previously observed for the reciprocal insulo-parietal propagation. Given that the parietal cortex receives somatosensory inputs from the oral cavity and the insular cortex receives primarily chemosensory inputs from the same source, the age-dependent changes in the availability of bidirectional signal traffic between these cortices might contribute to the development of multimodal responsiveness of taste neurons.
Hiroshi Yoshimura, Tokio Sugai, Mitsuhiro Fukuda, Natsuki Segami and Norihiko Onoda : Cortical spatial aspects of optical intrinsic signals in response to sucrose and NaCl stimuli., NeuroReport, Vol.15, No.1, 17-20, 2004.
(要約)
To examine whether cortical taste neurons use spatial codes for discriminating taste information, we investigated the spatial aspects of optical intrinsic signal (OIS) responses in the gustatory insular cortex (GC) elicited by the administration of two essential tastants, sucrose and NaCl, on the tongue. OIS responses to sucrose appeared in the rostral part of the GC, whereas those to NaCl appeared in the central part of the GC. Local anesthetization of the tongue abolished OIS responses, and the administration of distilled water elicited no OIS response. Thus, taste information elicited by sucrose and NaCl from the peripheral sensory organs is segregated in the GC, suggesting that the information from two essential tastants is assembled as spatial codes in the primary cortical taste area through the process of taste quality perception.
W Fu, T Sugai, Hiroshi Yoshimura and N Onoda : Convergence of olfactory and gustatory connections onto the endopiriform nucleus in the rat., Neuroscience, Vol.126, No.4, 1033-1041, 2004.
(要約)
Electrical and optical recordings were made from slice preparations including the piriform and gustatory cortices. Electrical stimulation of the gustatory cortex evoked a characteristic field potential in the endopiriform nucleus. A field potential was induced in the endopiriform nucleus by stimulation of the piriform cortex. Voltage-sensitive dye studies showed that stimulation of the piriform cortex induced signal propagation from the piriform cortex to endopiriform nucleus, whereas stimulation of the gustatory cortex did the same from the gustatory cortex to endopiriform nucleus via the agranular division of the insular cortex. After stimulation of the endopiriform nucleus, optical signals propagated not only to the piriform cortex but also to the gustatory cortex via the agranular division of the insular cortex. The olfactory and gustatory pathways appeared to be reciprocally connected. Unit recordings indicated that olfactory and gustatory activity converged onto a single neuron of the endopiriform nucleus. It is suggested that the cortical integration of olfactory and gustatory information could modulate mechanisms involved in food selection and emotional reactions relating to the chemical senses.
Hiroshi Yoshimura, Nobuo Kato, Tokio Sugai, Natsuki Segami and Norihiko Onoda : Age-dependent emergence of oscillatory signal flow between the primary and secondary visual cortices in rat brain slices., Brain Research, Vol.990, No.1-2, 172-181, 2003.
(要約)
Developmental changes in dynamics of signal propagation between the primary (Oc1) and secondary visual cortex (Oc2) were investigated by using optical recording methods with voltage-sensitive dyes. Propagating oscillatory optical responses were evoked by our previously reported procedure, and were recorded on stimulation to white matter of Oc1 in rat visual cortex slices. In immature slices, evoked signals spread out from the stimulation site by way of deep layers, but were restricted largely to Oc1. In mature slices, however, evoked signals spread upward from the stimulation site at first, and then spread out along layer II/III, finally to penetrate Oc2. More remarkably, after this initial signal was attenuated, oscillatory responses emerged and spread back from Oc2 to Oc1 by way of layer II/III, suggesting that the origin of backpropagating oscillation is located in Oc2. The initial forward component was dependent on both N-methyl-D-aspartate (NMDA) and non-NMDA receptors, and the subsequent backward components were dependent only on NMDA receptors. These results suggest that the extent of corticocoritcal signal propagation within the visual cortex grows wider horizontally during maturation, so that information interchange may become easier between the Oc1 and Oc2.
Keiseki Kaneyama, Natsuki Segami, Jun Sato, Masaaki Nishimura and Hiroshi Yoshimura : Expression of osteoprotegerin in synovial tissue and degradation of articular cartilage: comparison with arthroscopic findings of temporomandibular joint disorders., Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, Vol.96, No.3, 258-262, 2003.
(要約)
The expression of OPG might be associated with the development of degenerative changes of articular cartilage.
Hiroshi Yoshimura, Nobuo Kato, Tokio Sugai, Natsuki Segami and Norihiko Onoda : Age-dependent appearance of an insulo-parietal cortical signal propagation that elicits a synchronized population oscillation in the parietal cortex in rats., Brain Research. Developmental Brain Research, Vol.143, No.2, 245-251, 2003.
(要約)
We investigated postnatal development of a functional connectivity from the gustatory insular cortex to the parietal cortex, which is known to contain many more neurons responding to oral somesthetic stimulation than the insular cortex, in slices obtained from 9-35-day-old rats. Field potentials were evoked by stimulation to the insular cortex. In the mature cortex, insular stimulation elicited a solitary field potential in both the insular and parietal cortices and, as the simulation continued, the initial solitary potential came to be followed by a population oscillation of field potential in the parietal cortex, but not in the insular cortex. In the immature cortex, by contrast, insular stimulation failed to evoke both the initial solitary potential and the subsequent population oscillation in the parietal cortex. In the mature cortex, application of neither thapsigargin nor AP5 prevented elicitation of the initial solitary potential in the parietal cortex, but either of them abolished the parietal oscillation. In immature cortex bathed with low Mg(2+) medium, insular stimulation elicited both the initial solitary potential and the subsequent parietal oscillation, which were both prevented by thapsigargin or AP5. Theses results suggest that the insular and parietal cortices are anatomically connected but functionally unlinked at an early postnatal stage, and that a functional linkage, dependent both on NMDA and ryanodine receptors, is formed during the first postnatal month.
Natsuki Segami, Toshikazu Suzuki, Jun Sato, Masahisa Miyamaru, Masaaki Nishimura and Hiroshi Yoshimura : Does joint effusion on T2 magnetic resonance images reflect synovitis? Part 3. Comparison of histologic findings of arthroscopically obtained synovium in internal derangements of the temporomandibular joint., Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics, Vol.95, No.6, 761-766, 2003.
(要約)
The evidence of JE on MRI might correlate with synovial inflammatory activity. It confirms the common consensus that JE probably reflects synovitis, especially when synovial hyperplasia has a key role in the pathogenesis of JE.
Jun Sato, Natsuki Segami, Masaaki Nishimura, Hiroshi Yoshimura, Noboru Demura, Yoshino Yoshitake and Katsuzo Nishikawa : Correlation between the arthroscopic diagnosis of synovitis and microvessel density in synovial tissues in patients with internal derangement of the temporomandibular joint., Journal of Cranio-Maxillo-Facial Surgery, Vol.31, No.2, 101-106, 2003.
(要約)
Synovitis evaluated using Murakami's scores correlated well with the number of blood vessels in synovial tissues in patients with internal derangement of the TMJ. This demonstrates that synovitis is linked to inflammation-related blood vessel density of the synovial tissues.
J Sato, N Segami, M Nishimura, K Kaneyama, N Demura and Hiroshi Yoshimura : Relation between the expression of vascular endothelial growth factor in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging in patients with internal derangement of the temporomandibular joint., The British Journal of Oral & Maxillofacial Surgery, Vol.41, No.2, 88-94, 2003.
(要約)
The aim of this study is to elucidate the relation between the expression of vascular endothelial growth factor (VEGF) in synovial tissues and the extent of joint effusion seen on magnetic resonance imaging (MRI) in patients with internal derangement of the temporomandibular joint (TMJ). Using an immunohistochemical technique, we examined specimens of synovial tissues from 41 joints in 40 patients with internal derangement. Specimens from 36 of the 41 joints stained for VEGF. There was a significant correlation between the percentage of the VEGF-stained cells and the grade of joint effusion seen on MRI (P=0.0002, r=0.62). The correlation between the two was also significant on multiple logistic regression analysis (P=0.003, odds ratio=1.75). These results suggest that VEGF may have an important role in the genesis of joint effusion.
J Sato, N Segami, M Nishimura, N Demura, Hiroshi Yoshimura, Y Yoshitake and K Nishikawa : Expression of interleukin 6 in synovial tissues in patients with internal derangement of the temporomandibular joint., The British Journal of Oral & Maxillofacial Surgery, Vol.41, No.2, 95-101, 2003.
(要約)
Using an immunohistochemical technique, we examined synovial tissue from 46 temporomandibular joints (TMJ) with internal derangement in 44 patients. As controls, we examined synovial tissue specimens from 7 joints with habitual dislocation without pain. In synovial tissues from 21 of the 46 joints with internal derangement, interleukin 6 (IL-6) was expressed in the synovial lining cells and in the mononuclear cells infiltrating the periphery of the blood vessels. The density of IL-6-stained cells in specimens with internal derangement correlated significantly with the grade of joint effusion shown by magnetic resonance imaging (P=0.01, r=0.32).
Hiroshi Yoshimura, Tokio Sugai, Norihiko Onoda, Natsuki Segami and Nobuo Kato : Age-dependent occurrence of synchronized population oscillation suggestive of a developing functional coupling between NMDA and ryanodine receptors in the neocortex., Brain Research. Developmental Brain Research, Vol.136, No.1, 63-68, 2002.
(要約)
Synchronized population oscillation of delta to alpha range frequencies was synaptically induced in rat visual cortex neurons, depending on (1) the extent of N-methyl-D-aspartate (NMDA) receptor activation, (2) occurrence of calcium-induced calcium release (CICR), and (3) the age of animals. In adult slices bathed with 0.1 mM Mg(2+), as white matter stimulation continued, solitary synaptic potentials gradually became enlarged and overridden by small wavelets oscillating at alpha range frequencies. The calcium store depeletor thapsigargin prevented appearance of these wavelets. When Mg(2+) block of NMDA receptors was intensified with 0.5 or 2.0 mM Mg(2+), the oscillation failed to be induced, but became inducible by caffeine, which facilitates CICR. NMDA receptor blockade abolished induction of the oscillation even under caffeine application. In immature slices, the induction of oscillation was possible only with 0.1 mM Mg(2+) and bath-applied caffeine, but failed with 0.5 mM Mg(2+) or without caffeine. The oscillation induced in immature tissue was smaller in amplitude and frequency (delta-theta; range) than in adult tissue (alpha range). Immature tissue thus requires more restricted conditions for inducing the oscillation. We propose that NMDA and ryanodine receptors become coupled during maturation to enhance synaptically induced intracellular calcium releases, thereby facilitating induction of the oscillation at later stages.
Hiroshi Yoshimura, T Sugai, N Onoda, N Segami and N Kato : Synchronized population oscillation of excitatory synaptic potentials dependent of calcium-induced calcium release in rat neocortex layer II/III neurons., Brain Research, Vol.915, No.1, 94-100, 2001.
(要約)
We examined the roles played by calcium-induced calcium release from ryanodine-sensitive calcium stores in induction of neocortical membrane potential oscillation by using caffeine, an agonist of ryanodine receptors. Intracellular recordings were made from neurons in layer II/III of rat visual cortex slices in a caffeine-containing medium. White matter stimulation initially evoked monophasic synaptic potentials. As low-frequency stimulation continued for over 10 min, an oscillating synaptic potential gradually became evoked, in which a paroxysmal depolarization shift was followed by a 8-10-Hz train of several depolarizing wavelets. This oscillating potential was not induced in a medium containing no caffeine with 2 or 0.5 mM [Mg2+](o). Under blockade of N-methyl-D-aspartate receptors, induction of this oscillating potential failed even with caffeine application. Experiments with the calcium store depletor, thapsigargin, revealed that this oscillating potential is induced in a manner dependent on intracellular calcium release. Dual intracellular recordings revealed that the oscillation was synchronized in pairs of layer II/III neurons. The oscillating potential was detectable by field potential recordings also, suggesting that the present oscillation seems to reflect a network property.
Hiroshi Yoshimura and N Kato : Diverse roles of intracellular cAMP in early synaptic modifications in the rat visual cortex., The Journal of Physiology, Vol.522 Pt 3, 417-426, 2000.
(要約)
1. The effects of increasing intracellular cAMP concentration were studied using photolysis of caged-cAMP in layer II/III neurons recorded intracellularly in visual cortex slices. The recorded neurons exhibited either after-hyperpolarization (AHP) or after-depolarization (ADP) in response to depolarizing current injection. Depending on which afterpotential appeared, the effects of photolysis differed. 2. In ADP-generating neurons, photolysis of caged-cAMP induced long-lasting depression of postsynaptic potentials (PSPs) evoked by grey matter (GM) stimulation, without altering the size of the ADP. In AHP-generating neurons, photolysis induced long-lasting potentiation of GM-evoked PSPs, with the size of the AHP reduced in the same time course. White matter (WM)-evoked PSPs showed no change. 3. Extracellular application of bromo-cAMP depressed both GM- and WM-evoked PSPs in ADP- and AHP-generating neurons. This depression may be due to presynaptic effects of cAMP, since photolysis-evoked postsynaptic increase in cAMP concentration never induced depression of PSPs in AHP-generating neurons. This depression was reversible but continued until bromo-cAMP was washed out, while ADP and AHP in the postsynaptic neurons were depressed only temporarily and returned to the pre-application level even in the continued presence of bromo-cAMP. 4. Bromo-cAMP was applied following photolysis of caged-cAMP. In the neurons in which the photolysis potentiated GM-evoked PSPs this potentiation was cancelled out by bromo-cAMP (depotentiation). In the other neurons, PSPs were depressed only reversibly. 5. Thus, a postsynaptic increase in cAMP concentration exerts more diverse effects on synaptic plasticity than thus far reported, depending on the difference in neuronal intrinsic excitability and probably on how much, or the way in which, cAMP concentration is increased.
H Gemba, N Miki, K Sasaki, S Kyuhou, R Matsuzaki and Hiroshi Yoshimura : Motivation-dependent activity in the dorsolateral part of the prefrontal cortex in the monkey., Neuroscience Letters, Vol.230, No.2, 133-136, 1997.
(要約)
Field potentials were recorded on self-paced hand and mouth movements with implanted electrodes on the surface and at 2.0-3.0 mm depth in respective cortical areas in seven monkeys. Surface-negative (s-N), depth-positive (d-P) premovement slow potentials were recorded in the prefrontal cortex only when the movements were performed with an intense motivation for a reward. Such a motivation-dependent activity was mainly obtained in the rostral bank of the arcuate sulcus on both sides (except for the inferior limb of the arcuate sulcus in the left hemisphere). Three of the seven monkeys were also tasked with visuo-initiated hand movements. As motivation for reward decreased, s-N, d-P potentials at a latency of about 80 ms after stimulus onset became gradually smaller in the rostral bank of the arcuate sulcus in the right hemisphere. These facts suggest that motivation-dependent activity is represented in the dorsolateral part of the prefrontal cortex in monkeys, and that the cortical part is involved in motivational functions as well as in cognitive functions.
Hiroshi Yoshimura and N Kato : Attenuation of Mg2(+)-block of synaptic N-methyl-D-aspartate receptors in the visual cortex of rats raised under optic nerve blockade., Brain Research, Vol.733, No.1, 108-112, 1996.
(要約)
It has been known that the sensitive period for ocular dominance column plasticity is prolonged in animals raised under light deprivation. We tested whether this prolongation is related to a developmental change in Mg2+ block of N-methyl-D-aspartate (NMDA) receptors. Synaptic potentials were recorded intracellularly from visual cortex slices of rats whose optic nerves were blocked bilaterally by tetrodotoxin injected into the eyes for 2-4 weeks of age. In cells from normal rats, the amplitude of NMDA receptor-mediated synaptic potentials became smaller at more negative membrane potentials, and larger at more positive potentials, even at 0.1 mM [Mg2+]o. In cells from tetrodotoxin-treated rats, the voltage-dependence was significantly weaker than in cells from normal rats at 0.1 mM [Mg2+]o. Thus, Mg(2+)-block of synaptic NMDA receptors in the visual cortex may be regulated by optic nerve activity, and may thereby control the sensitivity to synaptic plasticity in an activity-dependent manner.
N Kato and Hiroshi Yoshimura : Reduced Mg2+ block of N-methyl-D-aspartate receptor-mediated synaptic potentials in developing visual cortex., Proceedings of the National Academy of Sciences of the United States of America, Vol.90, No.15, 7114-7118, 1993.
(要約)
Molecular cloning has demonstrated a diversity of artificially expressed N-methyl-D-aspartate (NMDA) receptors, implying a similar diversity of naturally occurring NMDA receptors in situ. Particularly significant was the success in expression of NMDA receptor classes exhibiting various sensitivities to Mg2+ block, a voltage-dependent channel blockade by Mg2+ that is essential to NMDA receptor functioning. Release from Mg2+ block often allows or facilitates the occurrence of long-term potentiation, a form of synaptic plasticity. Here we show that in the immature visual cortex, which is more susceptible to long-term potentiation than adult visual cortex, synaptically activated NMDA receptors, unlike those in the adult, have varying but clearly reduced sensitivities to Mg2+ block. We propose that the initially expressed, later-eliminated NMDA receptors exhibiting a reduced Mg2+ block may underlie the greater susceptibility to plasticity in the immature neocortex.
N Kato and Hiroshi Yoshimura : Facilitatory effects of substance P on the susceptibility to long-term potentiation in the visual cortex of adult rats., Brain Research, Vol.617, No.2, 353-356, 1993.
(要約)
We studied whether substance P (SP) facilitates induction of long-term potentiation (LTP) in adult rat visual cortex slices, using intracellular recordings of postsynaptic potentials (PSPs) elicited by white matter stimulation. Tetanic stimulation in normal medium induces no change of the PSP amplitude. In SP-containing medium, by contrast, tetanization potentiated the PSP amplitude in 5 over 7 cells examined. Although the other 2 cells underwent no change, the overall effect of SP was an increase in the probability of LTP induction. This effect of SP was canceled out by bath-application of the non-peptide antagonist CP96,345 (n = 7) or intracellular application of guanosine 5'-beta-thio-diphosphate (GDP beta S; n = 7). These results suggest that SP increased LTP susceptibility of neurons in the adult rat visual cortex through SP receptor-mediated mechanisms.
N Kato and Hiroshi Yoshimura : Tetanization during GABAA receptor activation induces long-term depression in visual cortex slices., Neuropharmacology, Vol.32, No.5, 511-513, 1993.
(要約)
In rat visual cortex slices, long-term depression of synaptic transmission was induced by tetanic stimulation to white matter during bath-application of the GABAA agonist muscimol. This result supports the view that a combination of presynaptic activity and postsynaptic inhibition leads to a depression of synaptic efficiency.
Chenjuan Yao, Tetsuya Akamatsu, Takahiro Hasegawa and Hiroshi Yoshimura : The Defense System of Oral Cavity: Lipopolysaccharide Induced Inflammatory Response in the Mice Salivary Gland, BIT's 1st Annual World Congress of Oral & Dental Medicine Conference Abstract Book, 107, 2014.
Tetsuya Akamatsu, Chenjuan Yao, Takahiro Hasegawa and Hiroshi Yoshimura : Salivary Gland Development, Differentiation, and Regeneration - Role of Subtilisin-like Proprotein Convertase PACE4/SPC4, BIT's 1st Annual World Congress of Oral & Dental Medicine Conference Abstract Book, 59, 2014.
Norihiko Onoda, Tokio Sugai and Hiroshi Yoshimura : Odor-intensity coding in the anterior piriform cortex., Chemical Senses, Vol.30 Suppl 1, i162-3, 2005.
Hiroshi Yoshimura, Tokio Sugai, Natsuki Segami and Norihiko Onoda : Chemotopic arrangement for taste quality discrimination in the cortical taste area., Chemical Senses, Vol.30 Suppl 1, i164-5, 2005.
Tokio Sugai, Hiroshi Yoshimura and Norihiko Onoda : Functional reciprocal connections between olfactory and gustatory pathways., Chemical Senses, Vol.30 Suppl 1, i166-7, 2005.
Kazuo Hosoi, Chenjuan Yao, Takahiro Hasegawa, Hiroshi Yoshimura and Tetsuya Akamatsu : Dynamics of Salivary Gland AQP5 under Normal and Pathologic Conditions, International Journal of Molecular Sciences, Vol.21, No.4, 1182, Feb. 2020.
Hiroshi Yoshimura : The potential of caffeine for functional modification from cortical synapses to neuron networks in the brain., Current Neuropharmacology, Vol.3, No.4, 309-316, Oct. 2005.
(要約)
Structure and function of the brain are use-dependent variables based on "synapse plasticity". Since synapses are driven by chemical transmitters, synaptic functions are liable to be modified by extrinsic chemicals displaying affinities for synaptic receptors or modulators. Caffeine is a widely used chemical substance that can invade synapses, and has several biochemical and metabolic actions on synaptic activities. This review focuses on the actions of caffeine on changes in structure and function in the region of the hippocampal formation and neocortex, which exhibit high synapse plasticity. At the synapse level, various synaptic receptors and channel activities are modulated by caffeine via mobilization of intracellular calcium, inhibition of phosphodiesterase, antagonism of adenosine receptors and GABA receptors. These actions of caffeine enable neurons to induce plastic changes in the properties of synaptic activities, such as synaptic transmission efficiency and morphology. At the network level, caffeine has the ability to activate cortical neural oscillators that deliver repetitive N-methyl-D-aspartate receptor-dependent signals to surrounding areas, causing strengthening of long-range inter-cortical communications. Caffeine might thus allow reorganization of cortical network functions via synaptic mobilizations.
Saori Maeda and Hiroshi Yoshimura : Enhancement of theta-frequency band electroencephalogram activities during unmatched olfactory taste stimulation, Oral Neuriscience 2019, Osaka, May 2019.
2.
Hiroshi Yoshimura : A strategy of NMDA receptor-dependent oscillation in the visual cortex of rats, The 9th Federation of the Asian and Oceanian Physiologial Societies Congress (FAOPS2019), Kobe, Mar. 2019.
(キーワード)
NMDA受容体 (NMDA-receptors) / neural oscillation
3.
Chenjuan Yao, Tetsuya Akamatsu, Takahiro Hasegawa and Hiroshi Yoshimura : Induced expression of a subtilisin-like proprotein convertase PACE4 in the regeneration model of rat submandibular gland., The 4th International Symposium on Salivary Glands in Honor of Niels Stensen, Okazaki (Japan), Nov. 2016.
4.
Tetsuya Akamatsu, Chenjuan Yao, Takahiro Hasegawa and Hiroshi Yoshimura : Sexual difference in the regeneration model of the rat submandibular gland., The 4th International Symposium on Salivary Glands in Honor of Niels Stensen, Okazaki (Japan), Nov. 2016.
5.
Takahiro Hasegawa, Chenjuan Yao, Tetsuya Akamatsu and Hiroshi Yoshimura : Post-translational modifications of water channel aquaporin-5 in salivary gland cells, Oral Neuroscience 2016, Oral Neuroscience 2016, Osaka, Oct. 2016.
6.
Hiroshi Yoshimura, Tetsuya Akamatsu, Chenjuan Yao and Takahiro Hasegawa : Synaptic plasticity in the brain -Roles of NMDA receptor- (Invited lecture at Nantong University), Sep. 2016.
(キーワード)
synaptic plasticity / NMDA受容体 (NMDA-receptors)
7.
Hiroshi Yoshimura : Enhancement of oscillatory activity in the endopiriform nucleus (EPN) of rats raised under abnormal oral conditions, Jun. 2016.
Hiroshi Yoshimura : Convergence of gustatory and olfactory information in the endopiriform nucleus of rats, The International Simposium on Neuroscience in Orofacial sensory-motor functions, Osaka, May 2015.
9.
Chenjuan Yao, Tetsuya Akamatsu, Takahiro Hasegawa and Hiroshi Yoshimura : The Defense System of Oral Cavity: Lipopolysaccharide Induced Inflammatory Response in the Mice Salivary Gland, BIT's 1st Annual International Congress of Oral & Dental Medicine, Session 9: Oral Immunological Diseases, Allergy and Inflammation, Haikou, China, Nov. 2014.
Takako Fukuda, Takashi Tominaga, Yoko Tominaga, Nobuo Kato and Hiroshi Yoshimura : Alternative strategy of neocortex for driving voltage-oscillator of rats, The 100th Anniversary Annual Meeting of The Physiological Society of Japan, Mar. 2023.
Hiroyuki Kanayama, Takako Fukuda, Takashi Tominaga, Yoko Tominaga, Nobuo Kato and Hiroshi Yoshimura : Baclofen attenuates activities of caffeine-induced neural oscillations in the somatosensory cortex of rat, The 45th annual meeting of the Japanese Neuroscience Society, Jul. 2022.
Maeda Saori, Miyachi Yuki, Takahiro Hasegawa, Chenjuan Yao, Tetsuya Akamatsu and Hiroshi Yoshimura : Influences of olfactory stimulation on taste perception: An electroencephalogram frequency analysis study, The 94th Annual Meeting of the Physiological Science of Japan, Mar. 2017.
Hiroshi Yoshimura, Takashi Tominaga and Yoko Tominaga : Cortical disinhibition-induced echo wave in the EPN of rat, The 39th Annual Meeting of the Japan Neuriscience Society, Jul. 2016.
Hiroshi Yoshimura, 川邊 真道, 須貝 外喜夫, 加藤 伸郎, Takahiro Hasegawa, Chenjuan Yao and Tetsuya Akamatsu : Influences of oral impairment on neural oscilltion and wave propagation in the neocortex of rats, 第38回日本神経科学大会, Jul. 2015.
Hiroshi Yoshimura, Sugai Tokio, Tominaga Takashi, Tominaga Yoko, Hasegawa Takahiro, Yao Chenjuan, Akamatsu Tetsuya and Kato Nobuo : Aspects of oscillatory wave propagation in the neocortex after neocortical legion of rats, Neuroscience Research Suppl, Vol.Suppl, Sep. 2014.