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Noboru Mizuno - One of the best experts on this subject based on the ideXlab platform.
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distribution of gephyrin immunoreactivity in the Trigeminal Motor Nucleus an immunohistochemical study in rats
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2012Co-Authors: Fuxing Zhang, Takeshi Kaneko, Noboru Mizuno, Ting Zhang, Hiroyuki Hioki, Guodong GaoAbstract:It has been established that a postsynaptic scaffolding protein, gephyrin, is essential for anchoring two main groups of inhibitory receptors, GABAA receptors (GABAARs) and glycine receptors (GlyRs), to the postsynaptic sites of neurons. The present study was primarily attempted to examine if expression patterns of gephyrin might be different between jaw-closing (JC) and jaw-opening (JO) motoneurons. The JC- and JO-motoneurons in the rat Trigeminal Motor Nucleus (Vm) were located in the dorsolateral (Vm.dl) and ventromedial (Vm.vm) divisions, respectively (Mizuno et al.,1975). Thus, immunoreactivity (IR) for gephyrin was investigated in the Vm: immunofluorescence histochemistry for gephyrin was combined with retrograde tract-tracing of fluorogold (FG), which was injected into nerves innervating JC-muscles or nerves innervating JO-muscles; neuronal cells were counterstained with propidium iodide (PI). The Vm.dl was discriminated from the Vm.vm by the presence of vesicular glutamate transporter 1 (VGLUT1)-immunopositive axon terminals, which were distributed in the Vm.dl but not in the Vm.vm (Pang et al., J Comp Neurol2009;512:595–612). Gephyrin-IR showed a punctate pattern of fluorescence, and motoneuronal profiles were coated with small clusters of gephyrin-immunopositive puncta throughout the Vm. The distribution density of such clusters was apparently higher in the Vm.dl than in the Vm.vm; this was confirmed quantitatively by a method similar to that described by Lorenzo et al. (Eur J Neurosci2006;23:3161–3170). On the basis of the present results, possible correlation between the distribution density of gephyrin clusters in the submembrane region of Vm motoneurons and that of axon terminals making inhibitory synapses on Vm motoneurons was discussed. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
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axon terminals expressing vesicular glutamate transporter vglut1 or vglut2 within the Trigeminal Motor Nucleus of the rat origins and distribution patterns
The Journal of Comparative Neurology, 2009Co-Authors: You-wang Pang, Kouichi Nakamura, Takeshi Kaneko, Kanghui Xiong, Noboru MizunoAbstract:Little is known about the significance of the two types of glutamatergic neurons (those expressing vesicular glutamate transporter VGLUT1 or VGLUT2) in the control of jaw movements. We thus examined the origin and distribution of axon terminals with VGLUT1 or VGLUT2 immunoreactivity within the Trigeminal Motor Nucleus (Vm) in the rat. The Vm was divided into the dorsolateral division (Vm.dl; jaw-closing motoneuron pool) and the ventromedial division (Vm.vm; jaw-opening motoneuron pool). VGLUT1-immunopositive terminals were seen within the Vm.dl only, whereas VGLUT2-immunopositive ones were distributed to both the Vm.dl and the Vm.vm. Transection of the Motor root eliminated almost all VGLUT1-immunopositive axons in the Vm.dl, with no changes of VGLUT2 immunoreactivity in the two divisions, indicating that the VGLUT1- and VGLUT2-immunopositive axons came from primary afferents in the mesencephalic Trigeminal Nucleus and preMotor neurons for the Vm, respectively. In situ hybridization histochemistry revealed that VGLUT2 neurons were much more numerous than VGLUT1 neurons in the regions corresponding to the reported premotoneuron pool for the Vm. The results of immunofluorescence labeling combined with anterograde tract tracing further indicated that preMotor neurons with VGLUT2 in the Trigeminal sensory nuclei, the supraTrigeminal region, and the reticular region ventral to the Vm sent axon terminals contacting Trigeminal motoneurons and that some of the VGLUT1-expressing preMotor neurons in the reticular region ventral to the Vm sent axon terminals to jaw-closing motoneurons. The present results suggested that the roles played by glutamatergic neurons in controlling jaw movements might be different between VGLUT1- and VGLUT2-expressing neurons.
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Projections from the caudal spinal Trigeminal Nucleus to commissural interneurons in the supraTrigeminal region : an electron microscope study in the rat
Neuroscience letters, 1998Co-Authors: Takeshi Kaneko, Sakashi Nomura, Noboru MizunoAbstract:Electron microscopic double-labeling study in the rat indicated that projection fibers from the caudal spinal Trigeminal Nucleus (Vc) were distributed ipsilaterally within the supraTrigeminal region (STR) capping the Trigeminal Motor Nucleus (Tm) and made synaptic contact with neurons projecting to the contralateral Tm. Nociceptive inputs to the Vc may reflexly control, via interneurons in the STR, the activities of Tm neurons innervating the masticatory, tensor tympani, and/or tensor veli palatine muscles.
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gabaergic and glycinergic neurons projecting to the Trigeminal Motor Nucleus a double labeling study in the rat
The Journal of Comparative Neurology, 1996Co-Authors: Masahiko Takada, Takeshi Kaneko, Noboru MizunoAbstract:The distribution of GABAergic and glycinergic preMotor neurons projecting to the Trigeminal Motor Nucleus (Vm) was examined in the lower brainstem of the rat by a double labeling method combining retrograde axonal tracing with immunofluorescence histochemistry. After injection of the fluorescent retrograde tracer, tetramethylrhodamine dextran amine (TRDA), into the Vm unilaterally, neurons labeled with TRDA were seen ipsilaterally in the mesencephalic Trigeminal Nucleus, and bilaterally in the parabrachial region, the supraTrigeminal and interTrigeminal regions, the reticular formation just medial to the Vm, the principal sensory and spinal Trigeminal nuclei, the pontine and medullary reticular formation, especially the parvicellular part of the medullary reticular formation, the alpha part of the gigantocellular reticular Nucleus, and the medullary raphe nuclei. Some of these neurons labeled with TRDA were found to display glutamic acid decarboxylase (the enzyme involved in GABA synthesis)-like or glycine-like immunoreactivity. Such double-labeled neurons were seen mainly in the supraTrigeminal region, the reticular region adjacent to the medial border of the Vm, and the dorsal part of the lateral reticular formation of the medulla oblongata; a number of them were further scattered in the interTrigeminal region, the alpha part of the gigantocellular reticular Nucleus, the Nucleus raphe magnus, the principal sensory Trigeminal Nucleus, and the interpolar subNucleus of the spinal Trigeminal Nucleus. These neurons were considered to be inhibitory (GABAergic or glycinergic) neurons sending their axons to motoneurons in the Vm, or to local interneurons within and around the Vm.
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preMotor neurons for Trigeminal Motor Nucleus neurons innervating the jaw closing and jaw opening muscles differential distribution in the lower brainstem of the rat
The Journal of Comparative Neurology, 1995Co-Authors: Masahiko Takada, Takeshi Kaneko, Noboru MizunoAbstract:The distribution of preMotor neurons for Trigeminal Motor Nucleus neurons innervating the jaw-closing and jaw-opening muscles was examined in the lower brainstem of the rat by using retrograde and anterograde labeling techniques. First, Fluorogold, a fluorescent retrograde tracer, was injected into the dorsolateral or ventromedial division of the Trigeminal Motor Nucleus, each of which contains motoneurons innervating the jaw-closing or jaw-opening muscles, respectively. Second, Phaseolus vulgaris-leucoagglutinin, an anterograde tracer, was injected into each of the lower brainstem sites, where clusters of retrogradely labeled preMotor neurons had been seen in the first set of experiments. Third, after injection of the anterograde tracer into a lower brainstem site, followed by injection of the retrograde tracer cholera toxin B subunit into a masticatory muscle, termination of anterogradely labeled axons onto retrogradely labeled motoneurons was confirmed with the aid of a confocal laser-scanning microscope. It was found that the preMotor neurons distributed in the mesencephalic Trigeminal Nucleus, medial part of the parabrachial region, supraTrigeminal region, and dorsal parts of the principal sensory, oral spinal and interpolar spinal Trigeminal nuclei project preferentially to the dorsolateral division of the Trigeminal Motor Nucleus, whereas those in the lateral part of the parabrachial region, intermediate parts of the principal sensory, oral spinal and interpolar spinal Trigeminal nuclei, and alpha part of the gigantocellular reticular Nucleus project preferentially to the ventromedial division of the Trigeminal Motor Nucleus. The dorsal and lateral parts of the medullary reticular formation and the medullary raphe nuclei contain preMotor neurons of both types. Group k motoneurons, a cluster of Trigeminal motoneurons that innervate the tensor tympani muscle, receive projection fibers predominantly from the dorsolateral part of the oral pontine reticular formation.
Arlette Kolta - One of the best experts on this subject based on the ideXlab platform.
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functional connectivity between the Trigeminal main sensory Nucleus and the Trigeminal Motor Nucleus
Frontiers in Cellular Neuroscience, 2020Co-Authors: Mohammed Slaoui Hasnaoui, Dorly Verdier, Isabel Arsenault, Sami Obeid, Arlette KoltaAbstract:The present study shows new evidence of functional connectivity between the Trigeminal main sensory (NVsnpr) and Motor (NVmt) nuclei in rats and mice. NVsnpr neurons projecting to NVmt are most highly concentrated in its dorsal half. Their electrical stimulation induced multiphasic excitatory synaptic responses in Trigeminal MNs and evoked calcium responses mainly in the jaw-closing region of NVmt. Induction of rhythmic bursting in NVsnpr neurons by local applications of BAPTA also elicited rhythmic firing or clustering of postsynaptic potentials in Trigeminal motoneurons, further emphasizing the functional relationship between these two nuclei in terms of rhythm transmission. Biocytin injections in both nuclei and calcium-imaging in one of the two nuclei during electrical stimulation of the other revealed a specific pattern of connectivity between the two nuclei, which organization seemed to critically depend on the dorsoventral location of the stimulation site within NVsnpr with the most dorsal areas of NVsnpr projecting to the dorsolateral region of NVmt and intermediate areas projecting to ventromedial NVmt. This study confirms and develops earlier experiments by exploring the physiological nature and functional topography of the connectivity between NVsnpr and NVmt that was demonstrated in the past with neuroanatomical techniques.
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generation of the masticatory central pattern and its modulation by sensory feedback
Progress in Neurobiology, 2012Co-Authors: Philippe Morquette, Dorly Verdier, Raphael A Lavoie, Mitchdavid Fhima, Xavier Lamoureux, Arlette KoltaAbstract:Abstract The basic pattern of rhythmic jaw movements produced during mastication is generated by a neuronal network located in the brainstem and referred to as the masticatory central pattern generator (CPG). This network composed of neurons mostly associated to the Trigeminal system is found between the rostral borders of the Trigeminal Motor Nucleus and facial Nucleus. This review summarizes current knowledge on the anatomical organization, the development, the connectivity and the cellular properties of these Trigeminal circuits in relation to mastication. Emphasis is put on a population of rhythmogenic neurons in the dorsal part of the Trigeminal sensory Nucleus. These neurons have intrinsic bursting capabilities, supported by a persistent Na + current ( I NaP ), which are enhanced when the extracellular concentration of Ca 2+ diminishes. Presented evidence suggest that the Ca 2+ dependency of this current combined with its voltage-dependency could provide a mechanism for cortical and sensory afferent inputs to the Nucleus to interact with the rhythmogenic properties of its neurons to adjust and adapt the rhythmic output. Astrocytes are postulated to contribute to this process by modulating the extracellular Ca 2+ concentration and a model is proposed to explain how functional microdomains defined by the boundaries of astrocytic syncitia may form under the influence of incoming inputs.
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electrical properties of interneurons found within the Trigeminal Motor Nucleus
European Journal of Neuroscience, 2008Co-Authors: S Mcdavid, J P Lund, Dorly Verdier, Arlette KoltaAbstract:The Trigeminal Motor Nucleus contains the somata of motoneurons innervating the jaw muscles, but also those of interneurons that we have characterized morphologically and immunohistochemically previously. Here we compare their basic physiological characteristics and synaptic inputs from the peri-Trigeminal area (PeriV) to those of motoneurons using whole-cell recordings made with pipettes containing biocytin in brainstem slices of rats that had a tracer injected into their masseters. Values for input resistance, spike duration and overall duration of afterhyperpolarization (AHP) were greater for interneurons than for motoneurons. Some interneurons (44%) and motoneurons (33%) had an outward rectification during depolarization. Hyperpolarization-induced inward rectification was seen predominantly in interneurons (85% vs. 31% for motoneurons). Few interneurons (15%) showed depolarization and time-dependent firing frequency accommodation, while half (52%) of the motoneurons did. Rebound excitation at the offset of hyperpolarization was more common in interneurons than in motoneurons (62% vs. 34%). Both populations received synaptic inputs from PeriV. These inputs were predominantly excitatory and were mediated by non-N-methyl-d-aspartate glutamatergic receptors. Response latencies and rise times of the evoked potentials were longer in interneurons than in motoneurons, suggesting that some of the inputs to interneurons could be polysynaptic and/or occurring at distal dendritic locations. Miniature synaptic events could be seen in about half of the neurons in both populations. These results suggest that interneurons can be clearly distinguished from motoneurons on the basis of some electrophysiological properties like the input resistance and spike and AHP durations, and the kinetics of their synaptic inputs from adjacent areas.
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morphological and immunohistochemical characterization of interneurons within the rat Trigeminal Motor Nucleus
Neuroscience, 2006Co-Authors: S Mcdavid, J P Lund, Francois Auclair, Arlette KoltaAbstract:Three series of experiments were carried out to characterize interneurons located within the Trigeminal Motor Nucleus of young rats aged 5-24 days. Cholera toxin injections were made bilaterally into the masseter and, sometimes, digastric muscles to label motoneurons. In the first set of experiments, thick slices were taken from the pontine brainstem and cholera toxin-positive and cholera toxin-negative neurons located inside the Trigeminal Motor Nucleus were filled with biocytin through whole-cell recording patch electrodes. Positively identified motoneurons (cholera toxin+) of various shapes and sizes always had a thick, unbranched axon that entered the Motor root following a tight zigzag course. Many cholera toxin-negative neurons were also classified as motoneurons after biocytin filling based on this particularity of their axon. These are probably either fusiMotor motoneurons or motoneurons supplying other jaw muscles. The cholera toxin-negative neurons classified as interneurons differed markedly from motoneurons in that they had thin, usually branched axons that supplied the ipsilateral reticular region surrounding the Trigeminal Motor Nucleus (periTrigeminal area), the main Trigeminal sensory Nucleus, the Trigeminal mesencephalic Nucleus, the medial reticular formation of both sides, and the contralateral medial periTrigeminal area. Most often, their dendrites were arranged in bipolar arbors that extended beyond the borders of the Trigeminal Motor Nucleus into the periTrigeminal area. Immunohistochemistry against glutamate, GABA and glycine was used to further document the nature and distribution of putative interneurons. Immunoreactive neurons were uniformly distributed throughout the rostro-caudal extent of the Trigeminal Motor Nucleus. Their concentration seemed greater toward the edges of the Nucleus and they were scarce in the digastric motoneuron pool. Glutamate- outnumbered GABA- and glycine-immunoreactive neurons. There was no clear segregation between the three populations. In the final experiment, 1,1'-dioctadecyl-3,3,3',3'-tetra-methylindocarbocyanine perchlorate crystals were inserted into one Trigeminal Motor Nucleus in thick slices and allowed to diffuse for several weeks. This procedure marked commissural fibers and interneurons in the contralateral Trigeminal Motor Nucleus. Together these results conclusively support the existence of interneurons in the Trigeminal Motor Nucleus.
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properties and interconnections of Trigeminal interneurons of the lateral pontine reticular formation in the rat
Journal of Neurophysiology, 2001Co-Authors: M J Bourque, Arlette KoltaAbstract:Numerous evidence suggests that interneurons located in the lateral tegmentum at the level of the Trigeminal Motor Nucleus contribute importantly to the circuitry involved in mastication. However, ...
Masayuki Moritani - One of the best experts on this subject based on the ideXlab platform.
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projection and synaptic connectivity of Trigeminal mesencephalic Nucleus neurons controlling jaw reflexes
Journal of Oral Science, 2017Co-Authors: Atsushi Yoshida, Yoshitaka Nagase, Masayuki Moritani, Yong Chul BaeAbstract:Neurons in the Trigeminal mesencephalic Nucleus (Vmes) receive deep sensation (proprioception) from jaw-closing muscle spindles and periodontal ligaments and project primarily to the jaw-closing motoneuron pool (jaw-closing Nucleus) of the Trigeminal Motor Nucleus and to the supraTrigeminal Nucleus. Numerous articles have described the morphology and physiology of the central projections of Vmes afferents originating from the muscle spindles and periodontal ligaments. However, no report has provided a detailed description of projection and synaptic connectivity, especially of single afferents, and their functional implications. In this review, we reanalyze data obtained by single intra-axonal recording and labeling of functionally identified Vmes muscle spindle afferents and periodontal ligament afferents and by electron microscopic observation of their projection features and synaptic organization of boutons, to compare the data for the jaw-closing Nucleus and supraTrigeminal Nucleus. Our analysis shows that each Vmes afferent type has characteristic projection pattern and synaptic feature that may be important in jaw-reflex control.
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ultrastructural analysis of glutamate gaba and glycine immunopositive boutons from supraTrigeminal premotoneurons in the rat Trigeminal Motor Nucleus
Journal of Neuroscience Research, 2009Co-Authors: Sang Kyoo Paik, Masayuki Moritani, Atsushi Yoshida, Hyojeong Lee, Min Ki Choi, Yi Sul Cho, Mae Ja Park, Yun Sook Kim, Yong Chul BaeAbstract:The supraTrigeminal region (Vsup) is important for coordination of smooth jaw movement. However, little is known about the synaptic connections of the Vsup premotoneurons with the Trigeminal Motor neurons. In the present study, we examined axon terminals of Vsup premotoneurons in the contralateral Trigeminal Motor Nucleus (Vmo) by a combination of anterograde tracing with cholera toxin B-horseradish peroxidase (CTB-HRP), postembedding immunohistochemistry for the amino acid transmitters glutamate, GABA, and glycine, and electron microscopy. Tracer injections resulted in anterograde labeling of axon terminals of the Vsup premotoneurons in the Motor Trigeminal Nucleus (Vmo). The labeled boutons in Vmo exhibited immunoreactivity for glutamate, GABA, or glycine: glutamate-immunopositive boutons (69%) were more frequently observed than GABA- or glycine-immunopositive boutons (19% and 12%, respectively). Although most labeled boutons (97%) made synaptic contacts with a single postsynaptic dendrite, a few glutamate-immunopositive boutons (3%) showed synaptic contact with two dendrites. No labeled boutons participated in axoaxonic synaptic contacts. Most labeled boutons (78%) were presynaptic to dendritic shafts, and the remaining 22% were presynaptic to somata or primary dendrites. A large proportion of GABA- or glycine-immunopositive boutons (40%) were presynaptic to somata or primary dendrites, whereas most glutamate-immunopositive boutons (86%) were presynaptic to dendritic shafts. These results indicate that axon terminals of Vsup premotoneurons show simple synaptic connection with Vmo neurons. This may provide the anatomical basis for the neural information processing responsible for jaw movement control.
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jaw muscle spindle afferent pathways to the Trigeminal Motor Nucleus in the rat
The Journal of Comparative Neurology, 2001Co-Authors: Masayuki Moritani, Dean DessemAbstract:Neural pathways conveying proprioceptive feedback from the jaw muscles were studied in rats by combining retrograde and intracellular neuronal labeling. Initially, horseradish peroxidase was iontophoresed unilaterally into the Trigeminal Motor Nucleus (Vmo). Two days later, 1–5 jaw-muscle spindle afferent axons located in the mesencephalic Trigeminal Nucleus were physiologically identified and intracellularly stained with biotinamide. Stained mesencephalic Trigeminal jaw-muscle spindle afferent axon collaterals and boutons were predominantly distributed in the supraTrigeminal region (Vsup), Vmo, dorsomedial Trigeminal principal sensory Nucleus (Vpdm), parvicellular reticular formation (PCRt), alpha division of the parvicellular reticular formation (PCRtA), and dorsomedial portions of the spinal Trigeminal subnuclei oralis (Vodm), and interpolaris (Vidm). Numerous neurons retrogradely labeled with horseradish peroxidase from the Trigeminal Motor Nucleus were found bilaterally in the PCRt, PCRtA, Vodm, and Vidm. Retrogradely labeled neurons were also present contralaterally in the Vsup, Vpdm, Vmo, periTrigeminal zone, and bilaterally in the dorsal medullary reticular field. Putative contacts between intracellularly stained mesencephalic Trigeminal jaw-muscle spindle afferent boutons and Trigeminal preMotor neurons retrogradely labeled with horseradish peroxidase were found in the ipsilateral Vodm, PCRtA, and PCRt, as well as the contralateral Vsup, Vmo, Vodm, PCRt, and PCRtA. Thus, multiple disynaptic jaw-muscle spindle afferent-motoneuron circuits exist. These pathways are likely to convey long-latency jaw-muscle stretch reflexes and may contribute to stiffness regulation of the masticatory muscles. J. Comp. Neurol. 435:341–353, 2001. © 2001 Wiley-Liss, Inc.
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jaw muscle spindle afferent pathways to the Trigeminal Motor Nucleus in the rat
The Journal of Comparative Neurology, 2001Co-Authors: Pifu Luo, Masayuki Moritani, Dean DessemAbstract:Neural pathways conveying proprioceptive feedback from the jaw muscles were studied in rats by combining retrograde and intracellular neuronal labeling. Initially, horseradish peroxidase was iontophoresed unilaterally into the Trigeminal Motor Nucleus (Vmo). Two days later, 1-5 jaw-muscle spindle afferent axons located in the mesencephalic Trigeminal Nucleus were physiologically identified and intracellularly stained with biotinamide. Stained mesencephalic Trigeminal jaw-muscle spindle afferent axon collaterals and boutons were predominantly distributed in the supraTrigeminal region (Vsup), Vmo, dorsomedial Trigeminal principal sensory Nucleus (Vpdm), parvicellular reticular formation (PCRt), alpha division of the parvicellular reticular formation (PCRtA), and dorsomedial portions of the spinal Trigeminal subnuclei oralis (Vodm), and interpolaris (Vidm). Numerous neurons retrogradely labeled with horseradish peroxidase from the Trigeminal Motor Nucleus were found bilaterally in the PCRt, PCRtA, Vodm, and Vidm. Retrogradely labeled neurons were also present contralaterally in the Vsup, Vpdm, Vmo, periTrigeminal zone, and bilaterally in the dorsal medullary reticular field. Putative contacts between intracellularly stained mesencephalic Trigeminal jaw-muscle spindle afferent boutons and Trigeminal preMotor neurons retrogradely labeled with horseradish peroxidase were found in the ipsilateral Vodm, PCRtA, and PCRt, as well as the contralateral Vsup, Vmo, Vodm, PCRt, and PCRtA. Thus, multiple disynaptic jaw-muscle spindle afferent-motoneuron circuits exist. These pathways are likely to convey long-latency jaw-muscle stretch reflexes and may contribute to stiffness regulation of the masticatory muscles.
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central distribution of synaptic contacts of primary and secondary jaw muscle spindle afferents in the Trigeminal Motor Nucleus of the cat
The Journal of Comparative Neurology, 1998Co-Authors: Hiroto Kishimoto, Motohide Takemura, Yoshitaka Nagase, Masayuki Moritani, Atsushi Yoshida, Shinji Nakagawa, Barry J. Sessle, Takeshi Wada, Yoshio ShigenagaAbstract:Little is known about the differences of the terminations of group Ia and group II afferents within the brainstem or spinal cord. The present study was performed to classify cat jaw muscle spindle afferents by the use of succinylcholine (SCh) and to examine the morphological characteristics of the physiologically classified afferents at the light and electron microscopic levels through the use of the intra-axonal horseradish peroxidase (HRP) injection technique. The effects of SCh on stretch responses of 119 jaw muscle spindle afferents from the masseter were examined. The SCh converted the single skew distribution of the values for dynamic index (DI) into a bimodal one. Fifty-eight and 61 afferents were classified as group Ia and group II afferents, respectively. The central projections of 17 intra-axonally stained afferents (10 group Ia and 7 group II afferents) were examined. The spindle afferents terminated mainly in the supraTrigeminal Nucleus (Vsup), region h, and the dorsolateral subdivision of Trigeminal Motor Nucleus (Vmo.dl) but differed in the pattern of projections of group Ia and group II afferents. The proportion of group Ia afferent terminals was higher in Vmo.dl but lower in Vsup than that of group II afferents. In Vmo.dl, the proportion of group Ia afferent terminals was higher in the central region but lower in the more outer regions than that of group II afferents. The ultrastructure of serially sectioned afferent boutons (63 group Ia and 72 group II boutons) also was examined. The boutons from the two groups were distributed widely from the soma to small-diameter dendrites, but the frequency of synaptic contacts on proximal dendrites was higher in group Ia than group II afferents. The present study provides evidence that the two groups of jaw muscle spindle afferents differ in their central projection and the spatial distribution of their synaptic contacts on Vmo.dl neurons. J. Comp. Neurol. 391:50–63, 1998. © 1998 Wiley-Liss, Inc.
Atsushi Yoshida - One of the best experts on this subject based on the ideXlab platform.
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distinctive features of phox2b expressing neurons in the rat reticular formation dorsal to the Trigeminal Motor Nucleus
Neuroscience, 2017Co-Authors: Kouta Nagoya, Atsushi Yoshida, Kiyomi Nakayama, Shiro Nakamura, Ayako Mochizuki, Keiko Ikeda, Hiroshi Onimaru, Masaaki Kiyomoto, Fumihiko Sato, Kiyoshi KawakamiAbstract:Abstract Phox2b encodes a paired-like homeodomain-containing transcription factor essential for development of the autonomic nervous system. Phox2b-expressing (Phox2b+) neurons are present in the reticular formation dorsal to the Trigeminal Motor Nucleus (RdV) as well as the Nucleus of the solitary tract and parafacial respiratory group. However, the nature of Phox2b+ RdV neurons is still unclear. We investigated the physiological and morphological properties of Phox2b+ RdV neurons using postnatal day 2–7 transgenic rats expressing yellow fluorescent protein under the control of Phox2b. Almost all of Phox2b+ RdV neurons were glutamatergic, whereas Phox2b-negative (Phox2b−) RdV neurons consisted of a few glutamatergic, many GABAergic, and many glycinergic neurons. The majority (48/56) of Phox2b+ neurons showed low-frequency firing (LF), while most of Phox2b− neurons (35/42) exhibited high-frequency firing (HF) in response to intracellularly injected currents. All, but one, Phox2b+ neurons (55/56) did not fire spontaneously, whereas three-fourths of the Phox2b− neurons (31/42) were spontaneously active. K+ channel and persistent Na+ current blockers affected the firing of LF and HF neurons. The majority of Phox2b+ (35/46) and half of the Phox2b− neurons (19/40) did not respond to stimulations of the mesencephalic Trigeminal Nucleus, the Trigeminal tract, and the principal sensory Trigeminal Nucleus. Biocytin labeling revealed that about half of the Phox2b+ (5/12) and Phox2b− RdV neurons (5/10) send their axons to the Trigeminal Motor Nucleus. These results suggest that Phox2b+ RdV neurons have distinct neurotransmitter phenotypes and firing properties from Phox2b− RdV neurons and might play important roles in feeding-related functions including suckling and possibly mastication.
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projection and synaptic connectivity of Trigeminal mesencephalic Nucleus neurons controlling jaw reflexes
Journal of Oral Science, 2017Co-Authors: Atsushi Yoshida, Yoshitaka Nagase, Masayuki Moritani, Yong Chul BaeAbstract:Neurons in the Trigeminal mesencephalic Nucleus (Vmes) receive deep sensation (proprioception) from jaw-closing muscle spindles and periodontal ligaments and project primarily to the jaw-closing motoneuron pool (jaw-closing Nucleus) of the Trigeminal Motor Nucleus and to the supraTrigeminal Nucleus. Numerous articles have described the morphology and physiology of the central projections of Vmes afferents originating from the muscle spindles and periodontal ligaments. However, no report has provided a detailed description of projection and synaptic connectivity, especially of single afferents, and their functional implications. In this review, we reanalyze data obtained by single intra-axonal recording and labeling of functionally identified Vmes muscle spindle afferents and periodontal ligament afferents and by electron microscopic observation of their projection features and synaptic organization of boutons, to compare the data for the jaw-closing Nucleus and supraTrigeminal Nucleus. Our analysis shows that each Vmes afferent type has characteristic projection pattern and synaptic feature that may be important in jaw-reflex control.
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electrophysiological and morphological properties of rat supraTrigeminal preMotor neurons targeting the Trigeminal Motor Nucleus
Journal of Neurophysiology, 2014Co-Authors: Shiro Nakamura, Atsushi Yoshida, Kiyomi Nakayama, Ayako Mochizuki, Fumihiko Sato, Tahsinul Haque, Tomio InoueAbstract:The electrophysiological and morphological characteristics of preMotor neurons in the supraTrigeminal region (SupV) targeting the Trigeminal Motor Nucleus (MoV) were examined in neonatal rat brain stem slice preparations with Ca(2+) imaging, whole cell recordings, and intracellular biocytin labeling. First, we screened SupV neurons that showed a rapid rise in intracellular free Ca(2+) concentration ([Ca(2+)]i) after single-pulse electrical stimulation of the ipsilateral MoV. Subsequent whole cell recordings were generated from the screened SupV neurons, and their antidromic responses to MoV stimulation were confirmed. We divided the antidromically activated preMotor neurons into two groups according to their discharge patterns during the steady state in response to 1-s depolarizing current pulses: those firing at a frequency higher (HF neurons, n = 19) or lower (LF neurons, n = 17) than 33 Hz. In addition, HF neurons had a narrower action potential and a larger afterhyperpolarization than LF neurons. Intracellular labeling revealed that the axons of all HF neurons (6/6) and half of the LF neurons (4/9) entered the MoV from its dorsomedial aspect, whereas the axons of the remaining LF neurons (5/9) entered the MoV from its dorsolateral aspect. Furthermore, the dendrites of three HF neurons penetrated into the principal sensory Trigeminal Nucleus (Vp), whereas the dendrites of all LF neurons were confined within the SupV. These results suggest that the types of SupV preMotor neurons targeting the MoV with different firing properties have different dendritic and axonal morphologies, and these SupV neuron classes may play unique roles in diverse oral Motor behaviors, such as suckling and mastication.
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ultrastructural analysis of glutamate gaba and glycine immunopositive boutons from supraTrigeminal premotoneurons in the rat Trigeminal Motor Nucleus
Journal of Neuroscience Research, 2009Co-Authors: Sang Kyoo Paik, Masayuki Moritani, Atsushi Yoshida, Hyojeong Lee, Min Ki Choi, Yi Sul Cho, Mae Ja Park, Yun Sook Kim, Yong Chul BaeAbstract:The supraTrigeminal region (Vsup) is important for coordination of smooth jaw movement. However, little is known about the synaptic connections of the Vsup premotoneurons with the Trigeminal Motor neurons. In the present study, we examined axon terminals of Vsup premotoneurons in the contralateral Trigeminal Motor Nucleus (Vmo) by a combination of anterograde tracing with cholera toxin B-horseradish peroxidase (CTB-HRP), postembedding immunohistochemistry for the amino acid transmitters glutamate, GABA, and glycine, and electron microscopy. Tracer injections resulted in anterograde labeling of axon terminals of the Vsup premotoneurons in the Motor Trigeminal Nucleus (Vmo). The labeled boutons in Vmo exhibited immunoreactivity for glutamate, GABA, or glycine: glutamate-immunopositive boutons (69%) were more frequently observed than GABA- or glycine-immunopositive boutons (19% and 12%, respectively). Although most labeled boutons (97%) made synaptic contacts with a single postsynaptic dendrite, a few glutamate-immunopositive boutons (3%) showed synaptic contact with two dendrites. No labeled boutons participated in axoaxonic synaptic contacts. Most labeled boutons (78%) were presynaptic to dendritic shafts, and the remaining 22% were presynaptic to somata or primary dendrites. A large proportion of GABA- or glycine-immunopositive boutons (40%) were presynaptic to somata or primary dendrites, whereas most glutamate-immunopositive boutons (86%) were presynaptic to dendritic shafts. These results indicate that axon terminals of Vsup premotoneurons show simple synaptic connection with Vmo neurons. This may provide the anatomical basis for the neural information processing responsible for jaw movement control.
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quantitative ultrastructure of physiologically identified premotoneuron terminals in the Trigeminal Motor Nucleus in the cat
The Journal of Comparative Neurology, 2000Co-Authors: Yoshio Shigenaga, Atsushi Yoshida, Yohsuke Hirose, Hideyuki Fukami, Shiho Honma, Yong Chul BaeAbstract:Little is known about the ultrastructure of synaptic boutons contacting Trigeminal motoneurons. To address this issue, physiologically identified preMotor neurons (n = 5) in the rostrodorsomedial part of the oral Nucleus (Vo.r) were labeled by intracellular injections of horseradish peroxidase (HRP) in cats. The ultrastructure of 182 serially sectioned axon terminals from the five neurons was both qualitatively and quantitatively analyzed. In addition, the effects of the glycine antagonist strychnine, GABAA antagonist bicuculline, NMDA antagonist 2-amino-5-phosphonovalerate (APV), and non-NMDA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) on Vo.r-induced postsynaptic potentials in Trigeminal motoneurons (n = 11) were examined to evaluate potential signaling substances of the preMotor neurons. Labeled boutons made synaptic contacts with either jaw-closing or -opening motoneurons. All the boutons contained pleomorphic vesicles, and most formed a single symmetric synapse either on the somata or on primary dendrites. Morphometric analyses indicated that bouton volume, bouton surface area, apposed surface area, total active zone area, and mitochondrial volume were not different between boutons on jaw-closing and -opening motoneurons. Vesicle number and density, however, were higher for boutons on jaw-closing motoneurons. The five morphological parameters were positively correlated with bouton volume. Vesicle density was the exception, which tending to be negatively correlated. Intravenous infusion of strychnine or bicuculline suppressed Vo.r-induced inhibitory postsynaptic potentials (IPSPs) in jaw-closing motoneurons. Abolition of Vo.r-induced excitatory postsynaptic potentials in jaw-opening motoneurons with APV and CNQX unmasked IPSPs. The present results suggest that preMotor neurons in the Vo.r are inhibitory and that positive correlations between the ultrastructural parameters associated with synaptic release and bouton size are applicable to the interneurons, as they are in primary afferents. J. Comp. Neurol. 426:13–30, 2000. © 2000 Wiley-Liss, Inc.
Francisco R. Morales - One of the best experts on this subject based on the ideXlab platform.
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inhibition of excitatory synaptic transmission in the Trigeminal Motor Nucleus by the nitric oxide cyclicgmp signaling pathway
Brain Research, 2011Co-Authors: Inés Pose, Valentina Silveira, Francisco R. MoralesAbstract:Abstract Nitric oxide (NO) and cyclic GMP (cGMP) suppressed glutamatergic synaptic transmission to Trigeminal motoneurons in brain stem slices of neonatal rats. Histological studies showed guanylate cyclase (GC) containing fibers in the Trigeminal Motor pool. Glutamatergic excitatory postsynaptic currents (EPSCs) were recorded from neonatal Trigeminal motoneurons in response to stimulation of the supraTrigeminal Nucleus (SuV). The NO donors DETA/NONOate (DETA/NO), at a concentration which released 275.1 nM of NO, and Spermine/NONOate (Sper/NO) reduced the amplitude of the EPSC to 52.7 ± 0.6% and 60.1 ± 10.8% of control values, respectively. These actions were not blocked by the GC inhibitors, ODQ or NS-2028. However, in the presence of YC-1 or BAY41-2272, modulators of GC that act as NO sensitizers, lower and otherwise ineffective concentrations of DETA/NO induced a reduction of the EPSC to 60.6 ± 5.2%. Moreover, NO effects were mimicked by 8BrcGMP and by Zaprinast, an inhibitor of Phosphodiesterase 5. Glutamatergic currents evoked by exogenous glutamate were not reduced by DETA/NO nor 8BrcGMP. Paired-pulse facilitation was increased by NO donors. Under “minimal stimulation” conditions NO donors and cGMP increased the failure rate of evoked EPSCs. Protein kinase inhibitors antagonized cGMP effects. The results suggest that NO, through the synthesis of cGMP, presynaptically inhibits glutamatergic synaptic transmission on Trigeminal motoneurons. We propose that NO has complex actions on Motor pools; specific studies are needed to elucidate their physiological significance in the behaving animal.
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Direct hypothalamic innervation of the Trigeminal Motor Nucleus: a retrograde tracer study.
Neuroscience, 2005Co-Authors: R. Mcgregor, A. Damián, G. Fabbiani, Pablo Torterolo, Inés Pose, Michael H. Chase, Francisco R. MoralesAbstract:It is currently thought that the hypothalamus influences Motor output through connections with preMotor structures which in turn project to Motor nuclei. However, hypocretinergic/orexinergic projections to different Motor pools have recently been demonstrated. The present study was undertaken to examine whether hypocretinergic/orexinergic neurons are the only source of projections from the hypothalamus to the Trigeminal Motor Nucleus in the guinea-pig. Cholera toxin subunit b was injected into the Trigeminal Motor Nucleus in order to retrogradely label preMotor neurons. Two anatomically separated populations of labeled neurons were observed in the hypothalamus: one group was distributed along the dorsal zone of the lateral hypothalamic area, the lateral portion of the dorsomedial hypothalamic Nucleus and the perifornical Nucleus; the other was located within the periventricular portion of the dorsomedial hypothalamic Nucleus. Numerous cholera toxin subunit b+ neurons in both populations displayed glutamate-like immunoreactivity. In addition, preMotor neurons containing hypocretin/orexin were distributed throughout the lateral dorsomedial hypothalamic Nucleus, perifornical Nucleus and lateral hypothalamic area. Other preMotor neurons were immunostained for melanin concentrating hormone; these cells, which were located within the lateral hypothalamic area and the perifornical Nucleus, were intermingled with glutamatergic and hypocretinergic/orexinergic neurons. Nitrergic preMotor neurons were located only in the periventricular zone of the dorsomedial hypothalamic Nucleus. None of the hypothalamic preMotor neurons were GABAergic, cholinergic or monoaminergic. The existence of diverse neurotransmitter systems projecting from the hypothalamus to the Trigeminal Motor pool indicates that this diencephalic structure may influence the numerous functions that are subserved by the Trigeminal Motor system.
