The Experts below are selected from a list of 8742 Experts worldwide ranked by ideXlab platform
Carey D. Balaban - One of the best experts on this subject based on the ideXlab platform.
-
Immunohistochemical and biomolecular identification of melatonin 1a and 1b receptors in rat Vestibular Nuclei.
Auris nasus larynx, 2011Co-Authors: Seong-ki Ahn, Roza Khalmuratova, Young-sool Hah, Sea-yuong Jeon, Dong Gu Hur, Hung-soo Kang, Carey D. BalabanAbstract:Abstract Objective The aim of this study was to examine the localizations and expressions of melatonin 1a (MT1a) and 1b (MT1b) receptors in rat Vestibular Nuclei by immunohistochemical staining and reverse transcriptase-polymerase chain reaction. Materials and methods Twenty male Sprague–Dawley rats were used in this study. Antibodies for the MT1a and MT1b receptors were used in 10 rats, respectively. A further 10 animals were sacrificed for RT-PCR. Tissues containing medial Vestibular Nuclei were selectively isolated from brain stem slices for RT-PCR. Results MT1a and MT1b receptor immunopositive neurons were found to be distributed throughout the four major Vestibular Nuclei. Both receptors were primarily detected in neuronal somata and their proximal dendrites. The presences of the mRNAs of the MT1a and MT1b receptors were confirmed by RT-PCR in medial Vestibular Nuclei and trigeminal ganglia. Conclusions The present study demonstrates, for the first time, that MT1a and MT1b receptors are localized and expressed in rat Vestibular Nuclei. This study provides additional insight into the role of melatonin receptors during Vestibular signal processing.
-
Colocalization of 5-HT1F receptor and calcitonin gene-related peptide in rat Vestibular Nuclei.
Neuroscience letters, 2009Co-Authors: Seong-ki Ahn, Roza Khalmuratova, Sea-yuong Jeon, Dong Gu Hur, Jin-pyeong Kim, Jung Je Park, Carey D. BalabanAbstract:Abstract The aim of this study was to determine whether calcitonin gene-related peptide (CGRP) colocalizes with 5-HT 1F receptor in rat Vestibular Nuclei using a double immunohistochemical staining procedure. The frequent co-occurrence of migraine and balance disorders suggests a pathophysiologic link between the two. However, the mechanism of migrainous vertigo has not been elucidated, though serotonin (5-HT) and its receptors are believed to involve in the pathogenesis of migrainous vertigo. Furthermore, 5-HT 1F receptor agonists and CGRP receptor antagonists have recently attracted attention as potential treatments for migraine, and CGRP release from trigeminal neurons has been associated with migraine. This study demonstrates the colocalization of 5-HT 1F receptor and CGRP in the rat Vestibular Nuclei, which suggests that 5-HT 1F receptor regulates the release of CGRP from Vestibular Nuclei. This finding indicates that 5-HT 1F receptor agonists may ameliorate migrainous vertigo by attenuating elevated levels of CGRP release from Vestibular Nuclei.
-
Colocalization of 5-HT1F receptor and glutamate in neurons of the Vestibular Nuclei in rats.
Neuroreport, 2009Co-Authors: Seong-ki Ahn, Roza Khalmuratova, Sea-yuong Jeon, Dong Gu Hur, Jin-pyeong Kim, Jung Je Park, Dae Woo Kim, Carey D. BalabanAbstract:Interplay between migraine and balance disorder morbidities has been a topic of interest for many years. Serotonin (5-HT) receptor is closely related with migraine and is associated with Vestibular symptoms. The mechanism underlying migrainous vertigo, however, has not been determined. 5.HT 1F receptor has recently attracted attention in the treatment of migraine, and the release of glutamate from trigeminal neurons has been implicated in migraine. In this study, the authors observed the colocalization of 5-HT 1F receptor and glutamate in the Vestibular Nuclei of rats using double immunofluorescence, which suggests that 5-HT 1F receptor might modulate glutamate release from the Vestibular Nuclei. The results of this study suggest that 5.HT 1F receptor agonists represent a potential therapeutic strategy for migraine and balance disorders by blocking the elease of glutamate.
-
selective anterograde tracing of the individual serotonergic and nonserotonergic components of the dorsal raphe nucleus projection to the Vestibular Nuclei
Neuroscience, 2007Co-Authors: Adam L Halberstadt, Carey D. BalabanAbstract:Abstract It is well known that the dorsal raphe nucleus (DRN) sends serotonergic and nonserotonergic projections to target regions in the brain stem and forebrain, including the Vestibular Nuclei. Although retrograde tracing studies have reported consistently that there are differences in the relative innervation of different target regions by serotonergic and nonserotonergic DRN neurons, the relative termination patterns of these two projections have not been compared using anterograde tracing methods. The object of the present investigation was to trace anterogradely the individual serotonergic and nonserotonergic components of the projection from DRN to the Vestibular Nuclei in rats. To trace nonserotonergic DRN projections, animals were pretreated with the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT), and then, after 7 days, the anterograde tracer biotinylated dextran amine (BDA) was iontophoretically injected into the DRN. In animals treated with 5,7-DHT, nonserotonergic BDA-labeled fibers were found to descend exclusively within the ventricular plexus and to terminate predominantly within the periventricular aspect of the Vestibular Nuclei. Serotonergic DRN projections were traced by injecting 5,7-DHT directly into DRN, and amino–cupric–silver staining was used to visualize the resulting pattern of terminal degeneration. Eighteen hours after microinjection of 5,7-DHT into the DRN, fine-caliber degenerating serotonergic terminals were found within the region of the medial Vestibular nucleus (MVN) that borders the fourth ventricle, and a mixture of fine- and heavier-caliber degenerating serotonergic terminals was located further laterally within the Vestibular nuclear complex. These findings indicate that fine-caliber projections from serotonergic and nonserotonergic DRN neurons primarily innervate the periventricular regions of MVN, whereas heavier-caliber projections from serotonergic DRN neurons innervate terminal fields located in more lateral regions of the Vestibular Nuclei. Thus, serotonergic and nonserotonergic DRN axons target distinct but partially overlapping terminal fields within the Vestibular nuclear complex, raising the possibility that these two DRN projection systems are organized in a manner that permits regionally-specialized regulation of processing within the Vestibular Nuclei.
-
selective anterograde tracing of the individual serotonergic and nonserotonergic components of the dorsal raphe nucleus projection to the Vestibular Nuclei
Neuroscience, 2007Co-Authors: Adam L Halberstadt, Carey D. BalabanAbstract:Abstract It is well known that the dorsal raphe nucleus (DRN) sends serotonergic and nonserotonergic projections to target regions in the brain stem and forebrain, including the Vestibular Nuclei. Although retrograde tracing studies have reported consistently that there are differences in the relative innervation of different target regions by serotonergic and nonserotonergic DRN neurons, the relative termination patterns of these two projections have not been compared using anterograde tracing methods. The object of the present investigation was to trace anterogradely the individual serotonergic and nonserotonergic components of the projection from DRN to the Vestibular Nuclei in rats. To trace nonserotonergic DRN projections, animals were pretreated with the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT), and then, after 7 days, the anterograde tracer biotinylated dextran amine (BDA) was iontophoretically injected into the DRN. In animals treated with 5,7-DHT, nonserotonergic BDA-labeled fibers were found to descend exclusively within the ventricular plexus and to terminate predominantly within the periventricular aspect of the Vestibular Nuclei. Serotonergic DRN projections were traced by injecting 5,7-DHT directly into DRN, and amino–cupric–silver staining was used to visualize the resulting pattern of terminal degeneration. Eighteen hours after microinjection of 5,7-DHT into the DRN, fine-caliber degenerating serotonergic terminals were found within the region of the medial Vestibular nucleus (MVN) that borders the fourth ventricle, and a mixture of fine- and heavier-caliber degenerating serotonergic terminals was located further laterally within the Vestibular nuclear complex. These findings indicate that fine-caliber projections from serotonergic and nonserotonergic DRN neurons primarily innervate the periventricular regions of MVN, whereas heavier-caliber projections from serotonergic DRN neurons innervate terminal fields located in more lateral regions of the Vestibular Nuclei. Thus, serotonergic and nonserotonergic DRN axons target distinct but partially overlapping terminal fields within the Vestibular nuclear complex, raising the possibility that these two DRN projection systems are organized in a manner that permits regionally-specialized regulation of processing within the Vestibular Nuclei.
Adam L Halberstadt - One of the best experts on this subject based on the ideXlab platform.
-
projections from the Vestibular Nuclei and nucleus prepositus hypoglossi to dorsal raphe nucleus in rats
Neuroscience Letters, 2008Co-Authors: Bruna Cuccurazzu, Adam L HalberstadtAbstract:The serotonergic system regulates processing in components of the Vestibular nuclear complex, including the medial Vestibular nucleus (MVe) and nucleus prepositus hypoglossi (PH). Recent studies using anterograde and retrograde tracers have shown that Vestibular Nuclei are targeted by regionally selective projections from the serotonergic dorsal raphe nucleus. The objective of the present investigation was to determine whether the DRN is targeted by projections from the Vestibular nuclear complex in rats, using the anterograde tracer biotinylated dextran amine (BDA). After injection of BDA into PH or the caudal parvicellular division of MVe, labeled fibers and terminals were observed in the ventromedial and lateral subdivisions of DRN. These findings indicate that projections from the Vestibular Nuclei and PH are organized to modulate processing within specific functional domains of the DRN.
-
selective anterograde tracing of the individual serotonergic and nonserotonergic components of the dorsal raphe nucleus projection to the Vestibular Nuclei
Neuroscience, 2007Co-Authors: Adam L Halberstadt, Carey D. BalabanAbstract:Abstract It is well known that the dorsal raphe nucleus (DRN) sends serotonergic and nonserotonergic projections to target regions in the brain stem and forebrain, including the Vestibular Nuclei. Although retrograde tracing studies have reported consistently that there are differences in the relative innervation of different target regions by serotonergic and nonserotonergic DRN neurons, the relative termination patterns of these two projections have not been compared using anterograde tracing methods. The object of the present investigation was to trace anterogradely the individual serotonergic and nonserotonergic components of the projection from DRN to the Vestibular Nuclei in rats. To trace nonserotonergic DRN projections, animals were pretreated with the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT), and then, after 7 days, the anterograde tracer biotinylated dextran amine (BDA) was iontophoretically injected into the DRN. In animals treated with 5,7-DHT, nonserotonergic BDA-labeled fibers were found to descend exclusively within the ventricular plexus and to terminate predominantly within the periventricular aspect of the Vestibular Nuclei. Serotonergic DRN projections were traced by injecting 5,7-DHT directly into DRN, and amino–cupric–silver staining was used to visualize the resulting pattern of terminal degeneration. Eighteen hours after microinjection of 5,7-DHT into the DRN, fine-caliber degenerating serotonergic terminals were found within the region of the medial Vestibular nucleus (MVN) that borders the fourth ventricle, and a mixture of fine- and heavier-caliber degenerating serotonergic terminals was located further laterally within the Vestibular nuclear complex. These findings indicate that fine-caliber projections from serotonergic and nonserotonergic DRN neurons primarily innervate the periventricular regions of MVN, whereas heavier-caliber projections from serotonergic DRN neurons innervate terminal fields located in more lateral regions of the Vestibular Nuclei. Thus, serotonergic and nonserotonergic DRN axons target distinct but partially overlapping terminal fields within the Vestibular nuclear complex, raising the possibility that these two DRN projection systems are organized in a manner that permits regionally-specialized regulation of processing within the Vestibular Nuclei.
-
selective anterograde tracing of the individual serotonergic and nonserotonergic components of the dorsal raphe nucleus projection to the Vestibular Nuclei
Neuroscience, 2007Co-Authors: Adam L Halberstadt, Carey D. BalabanAbstract:Abstract It is well known that the dorsal raphe nucleus (DRN) sends serotonergic and nonserotonergic projections to target regions in the brain stem and forebrain, including the Vestibular Nuclei. Although retrograde tracing studies have reported consistently that there are differences in the relative innervation of different target regions by serotonergic and nonserotonergic DRN neurons, the relative termination patterns of these two projections have not been compared using anterograde tracing methods. The object of the present investigation was to trace anterogradely the individual serotonergic and nonserotonergic components of the projection from DRN to the Vestibular Nuclei in rats. To trace nonserotonergic DRN projections, animals were pretreated with the serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT), and then, after 7 days, the anterograde tracer biotinylated dextran amine (BDA) was iontophoretically injected into the DRN. In animals treated with 5,7-DHT, nonserotonergic BDA-labeled fibers were found to descend exclusively within the ventricular plexus and to terminate predominantly within the periventricular aspect of the Vestibular Nuclei. Serotonergic DRN projections were traced by injecting 5,7-DHT directly into DRN, and amino–cupric–silver staining was used to visualize the resulting pattern of terminal degeneration. Eighteen hours after microinjection of 5,7-DHT into the DRN, fine-caliber degenerating serotonergic terminals were found within the region of the medial Vestibular nucleus (MVN) that borders the fourth ventricle, and a mixture of fine- and heavier-caliber degenerating serotonergic terminals was located further laterally within the Vestibular nuclear complex. These findings indicate that fine-caliber projections from serotonergic and nonserotonergic DRN neurons primarily innervate the periventricular regions of MVN, whereas heavier-caliber projections from serotonergic DRN neurons innervate terminal fields located in more lateral regions of the Vestibular Nuclei. Thus, serotonergic and nonserotonergic DRN axons target distinct but partially overlapping terminal fields within the Vestibular nuclear complex, raising the possibility that these two DRN projection systems are organized in a manner that permits regionally-specialized regulation of processing within the Vestibular Nuclei.
-
anterograde tracing of projections from the dorsal raphe nucleus to the Vestibular Nuclei
Neuroscience, 2006Co-Authors: Adam L Halberstadt, Carey D. BalabanAbstract:Abstract This study used the anterograde transport of biotinylated dextran amine (BDA) to identify the course and terminal distribution of projections from the dorsal raphe nucleus (DRN) to the Vestibular Nuclei in rats. After iontophoretic injection of BDA into the medial and lateral regions of DRN, anterogradely labeled fibers descend within the medial longitudinal fasciculus and the ventricular fiber plexus to terminate within two discrete regions of the Vestibular nuclear complex. One terminal field was located primarily ipsilateral to the injection site and involved rostrodorsal aspects of the Vestibular Nuclei, including superior Vestibular nucleus and rostral portions of the medial Vestibular nucleus (MVN) and lateral Vestibular nucleus (LVN). The other terminal field involved caudoventral aspects of both ipsilateral and contralateral MVN and LVN and was less heavily innervated. These findings confirm that the Vestibular Nuclei are targeted by a regionally-selective projection from the DRN. The segregation of DRN terminals into anatomically distinct fields indicates that the DRN-Vestibular nucleus projections are organized to selectively modulate processing within specific functional domains of the Vestibular nuclear complex. In particular, these terminal fields may be organized to modulate Vestibular regions involved in eye movement–related velocity storage, coordination of Vestibular and affective responses, and the bilateral coordination of horizontal eye movement reflexes.
-
serotonergic and nonserotonergic neurons in the dorsal raphe nucleus send collateralized projections to both the Vestibular Nuclei and the central amygdaloid nucleus
Neuroscience, 2006Co-Authors: Adam L Halberstadt, Carey D. BalabanAbstract:Using a combination of double retrograde tracing and serotonin immunofluorescence staining, we examined whether individual serotonergic and nonserotonergic neurons in the dorsal raphe nucleus are sources of collateralized axonal projections to Vestibular Nuclei and the central amygdaloid nucleus in the rat. Following unilateral injections of Diamidino Yellow into the Vestibular Nuclei and Fast Blue into the central amygdaloid nucleus, it was observed that approximately one-fourth of the dorsal raphe nucleus neurons projecting to the Vestibular Nuclei send axon collaterals to the central amygdaloid nucleus. Immunofluorescence staining for serotonin revealed that more than half of the dorsal raphe nucleus neurons from which these collateralized projections arise contain serotonin-like immunoreactivity. These findings indicate that a subpopulation of serotonergic and nonserotonergic dorsal raphe nucleus cells may act to co-modulate processing in the Vestibular Nuclei and the central amygdaloid nucleus, regions implicated in the generation of emotional and affective responses to real and perceived motion.
Byung-rim Park - One of the best experts on this subject based on the ideXlab platform.
-
Signaling pathway of glutamate in the Vestibular Nuclei following acute hypotension in rats
Brain research, 2008Co-Authors: Myoung Ae Choi, Min Sun Kim, Jae Hee Lee, Ji Hyo Hwang, Suck Jun Choi, Byung-rim ParkAbstract:Acute hypotension induces excitation of electrical activity and expression of c-Fos protein and phosphorylated extracellular signal-regulated kinase (pERK) in the Vestibular Nuclei. Expression of c-Fos protein and pERK is mediated by the excitatory neurotransmitter, glutamate. In this study, in order to investigate the signaling pathway of glutamate in the Vestibular Nuclei following acute hypotension, expression of the NR2B subunit of glutamate N-methyl-D-aspartate (NMDA) receptors and the GluR1 subunit of glutamate alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors was measured by Western blotting in the medial Vestibular nucleus (MVN) following acute hypotension in bilateral labyrinthectomized (BL) rats. In intact labyrinthine animals, acute hypotension increased expression of pGluR1 and pNR2B in the MVN. Expression of pGluR1 Ser831 and Ser845 peaked at 5 and 30 min after acute hypotension and expression of pNR2B peaked at 60 min after acute hypotension, respectively. In BL animals, expression of pGluR1 Ser831, pGluR1 Ser845, and pNR2B was decreased significantly compared to intact labyrinthine animals following acute hypotension. These results suggest that excitatory afferent signals from the peripheral Vestibular receptors, resulting from acute hypotension, release glutamate into postsynaptic neurons in the Vestibular Nuclei and the excitatory signals are transmitted through the GluR1 subunit of the AMPA receptors and the NR2B subunits of the NMDA receptors in the Vestibular system.
-
Effects of acute hypotension on expression of cFos-like protein in the Vestibular Nuclei of rats.
Brain research, 2003Co-Authors: Min Sun Kim, Jae Hyo Kim, Davy Kry, Myoung Ae Choi, Dong Ok Choi, Byung Gon Cho, Yuan Zhe Jin, Seong Ho Lee, Byung-rim ParkAbstract:The expression and regional distribution of cFos protein, which is an oncogene product and metabolic marker of neural excitation, were investigated in the Vestibular nuclear complex following acute hypotension in adult Sprague-Dawley rats. Intravenous administration of nitroprusside elicited a 10-50% reduction in mean blood pressure for 10 min. Unilateral or bilateral chemical labyrinthectomies were performed 14 days before the start of the experiment to eliminate afferent signals from the peripheral Vestibular receptors in the inner ear. All of the animals were sacrificed and the tissues were fixed 2 h after the onset of acute hypotension using the cardiac perfusion method for c-Fos immunohistochemical staining. The cFos-like immunoreactive (cFLI) neurons were expressed selectively in the central area of the medial Vestibular nucleus following a 10% reduction in blood pressure. Once the blood pressure had fallen by 30%, bilateral expression of cFLI neurons was observed in the superior, medial, and spinal Vestibular Nuclei, but not in the lateral Vestibular nucleus, of control rats with intact labyrinths. The expression of cFLI neurons increased proportionately with reductions in blood pressure. In unilaterally labyrinthectomized rats, acute hypotension induced the expression of cFLI neurons in Vestibular Nuclei contra lateral to the injured labyrinth, but not in the ipsilateral Vestibular Nuclei. However, cFLI neurons were not expressed in bilateral Vestibular Nuclei following acute hypotension in bilateral labyrinthectomized rats. These results suggest that afferent signals from the peripheral Vestibular receptors are essential for cFos protein expression in the Vestibular Nuclei following acute hypotension.
-
temporal changes of cfos like protein expression in medial Vestibular Nuclei following arsanilate induced unilateral labyrinthectomy in rats
Neuroscience Letters, 2002Co-Authors: Byung-rim ParkAbstract:The compensation of spontaneous nystagmus and head deviation following chemical unilateral labyrinthectomy (UL) induced by arsanilate was delayed compared with surgical UL. Surgical UL produced two phases of significant asymmetry of cFos-like (cFL) protein expression between the bilateral medial Vestibular Nuclei, with more expression in the contralateral medial Vestibular Nuclei to the injured side than in the ipsilateral medial Vestibular Nuclei 2 h after UL; the pattern reversed after 6 h and expression disappeared after 72 h. Chemical UL produced three phases of asymmetric expression, with more cFL protein expression in the contralateral medial Vestibular Nuclei than in the ipsilateral medial Vestibular Nuclei 6 h after UL and a reversed pattern after 12 h. Asymmetric expression 72 h after UL followed increased expression in the contralateral medial Vestibular Nuclei. These results suggest that the course of Vestibular compensation and the temporal expression of cFL protein in the medial Vestibular Nuclei following UL differed between surgical and chemical labyrinthectomy.
-
Neuronal Activity of the Vestibular Nuclei Following Acute Hypotension in Rats
The Korean Journal of Physiology and Pharmacology, 2002Co-Authors: Byung-rim Park, Min Sun Kim, Kum-hyun Baik, Moon-young Lee, Myung-ae Choi, Jae-hyo LeeAbstract:The role of peripheral Vestibular receptors in acute hypotension was investigated in anesthetized rats. Acute hypotension was induced by either intravenous infusion of sodium nitroprusside (SNP) or by experimental hemorrhage, and electrical activity and expression of cFos-like immunoreactive (cFL) protein were measured in the medial Vestibular Nuclei (MVN). Blood pressure decreased proportionately to the does of intravenous SNP and to the volume of the hemorrhage. Blood pressure decreased 10, 30, 50% for the 5, 10, SNP injection, respectively, and also decreased 30 and 50% after 1- and 2-ml blood loss, respectively, due to hemorrhage. In animals with intact labyrinths, acute hypotension induced by either intravenous infusion of SNP or hemorrhage produced different electrical activities with three different patterns in type I and II neurons of MVN. The responses of type I neurons showed excitatory in 2/3 of recorded neurons and inhibitory or no change in 1/3 of neurons, while the responses of type II neurons showed inhibitory in 2/3 of recorded neurons and excitatory or no change in 1/3 of neurons. In unilateral labyrinthectomized animals, 2/3 of type I neurons ipsilateral to the lesion showed an inhibitory response, and 2/3 of contralateral type I neurons showed an excitatory response after the induction of acute hypotension. The response patterns of type II neurons were opposite from those of the type I neurons. After 30% decrease in blood pressure, cFL protein expressed in the bilateral Vestibular Nuclei of control animals with intact labyrinths. Expression of cFL protein increased significantly proportionately to the reduction of blood pressure. The unilateral labyrinthectomized animals with acute hypotension produced expression of cFL neurons in contralateral Vestibular Nuclei to the lesion side, but not in ipsilateral Vestibular Nuclei. However, cFL protein was not expressed in bilateral Vestibular Nuclei after acute hypotension in bilateral labyrinthectomized animals. These results suggest that the peripheral Vestibular receptors might play a significant role in controlling blood pressure following acute hypotension via activation of type I neurons and inhibition of type II neurons in the Vestibular Nuclei.
Mayank B. Dutia - One of the best experts on this subject based on the ideXlab platform.
-
histaminergic and glycinergic modulation of gaba release in the Vestibular Nuclei of normal and labyrinthectomised rats
The Journal of Physiology, 2006Co-Authors: Filip Bergquist, Alasdair Ruthven, Mike Ludwig, Mayank B. DutiaAbstract:Vestibular compensation (the behavioural recovery that follows unilateral Vestibular de-afferentation), is facilitated by histamine, and is associated with increased central histamine release and alterations in histamine H3 receptor expression in the Vestibular Nuclei. However, little is known of the effects of histamine on neurotransmission in the Vestibular Nuclei, and the mechanisms by which histamine may influence compensation are unclear. Here we examined the modulatory effects of histaminergic agents on the release of amino acid neurotransmitters in slices of the medial Vestibular nucleus (MVN) prepared from normal and labyrinthectomised rats. The release of GABA, but not glutamate, glycine or aspartate, was robustly and reproducibly evoked by a high-K+ stimulus applied to normal MVN slices. Histamine inhibited the evoked release of GABA, both through a direct action on presynaptic H3 receptors (presumably located on GABAergic terminals), and through a novel, indirect pathway that involved the increased release of glycine by activation of postsynaptic H1/H2 receptors (presumably on glycinergic neurons). After unilateral labyrinthectomy (UL), the direct H3 receptor-mediated inhibition of GABA release was profoundly downregulated in both ipsi-lesional and contra-lesional MVNs. This effect appeared within 25 h post-UL and persisted for at least 3 weeks post-UL. In addition, at 25 h post-UL the indirect glycinergic pathway caused a marked suppression of GABA release in the contra-lesional but not ipsi-lesional MVN, which was overcome by strychnine. Stimulation of histamine H3 receptors at 25 h post-UL restored contra-lesional GABA release to normal, suggesting that acutely after UL H3 receptors may strongly modulate glycinergic and GABAergic neurotransmission in the MVN. These findings are the first to demonstrate the modulatory actions of the histaminergic system on neurotransmission in the Vestibular Nuclei, and the changes that occur during Vestibular system plasticity. During Vestibular compensation, histaminergic modulation of glycine and GABA release may contribute to the rebalancing of neural activity in the Vestibular Nuclei of the lesioned and intact sides.
-
Changes in protein expression in the rat medial Vestibular Nuclei during Vestibular compensation
The Journal of Physiology, 2006Co-Authors: Janet M. Paterson, Duncan Short, Peter W. Flatman, Jonathan R. Seckl, Alastair Aitken, Mayank B. DutiaAbstract:The molecular mechanisms of neural and synaptic plasticity in the Vestibular Nuclei during ‘Vestibular compensation’, the behavioural recovery that follows deafferentation of one inner ear, are largely unknown. In this study we have used differential proteomics techniques to determine changes in protein expression in ipsi-lesional and contra-lesional medial Vestibular Nuclei (MVN) of rats, 1 week after either sham surgery or unilateral labyrinthectomy (UL). A systematic comparison of 634 protein spots in two-dimensional electrophoresis gels across five experimental conditions revealed 54 spots, containing 26 proteins whose level was significantly altered 1 week post-UL. The axon-guidance-associated proteins neuropilin-2 and dehydropyriminidase-related protein-2 were upregulated in the MVN after UL. Changes in levels of further specific proteins indicate a coordinated upregulation of mitochondrial function, ATP biosynthesis and phosphate metabolism in the Vestibular Nuclei 1 week post-UL. These may reflect the metabolic energy demands of processes such as gliosis, neuronal outgrowth and synaptic remodelling that occur after UL. Our findings suggest novel roles for axon elaboration and guidance molecules, as well as mitochondrial and metabolic regulatory proteins, in the post-lesional physiology of the MVN during Vestibular system plasticity.
C De Waele - One of the best experts on this subject based on the ideXlab platform.
-
An in situ hybridization and immunofluorescence study of glycinergic receptors and gephyrin in the Vestibular Nuclei of the intact and unilaterally labyrinthectomized rat.
Experimental brain research, 2003Co-Authors: Lyndell Eleore, Isabelle Vassias, P P Vidal, C De WaeleAbstract:We investigated whether the expression of glycinergic receptor (GLYR) subunits of gephyrin and of their mRNAs in the medial Vestibular Nuclei are affected following unilateral labyrinthectomy. Specific radioactive oligonucleotide probes recognizing the sequences encoding α1–3 and s subunits of GLYR and the anchoring protein gephyrin were used to probe sections of Vestibular Nuclei. Signals in these in situ hybridization experiments were detected with film or by emulsion photography. Animals were killed at various times following the lesion: 5 h, 1, 3, 8, 30 and 60 days. Specific monoclonal GLYR and gephyrin antibodies were also used to determine GLYR and gephyrin immunoreactivity in control and operated rats (5 h, 1, 3 and 8 days post-lesion). In normal animals, several brainstem regions including the lateral, medial, superior and inferior Vestibular Nuclei contained mRNAs for gephyrin and the α1 and β subunits of GLYR, and expressed the GLYR and gephyrin polypeptides. In unilaterally labyrinthectomized rats, no asymmetry was detected on autoradiographs between the two medial Vestibular Nuclei with any of the oligonucleotide probes used, or at any time following the lesion. No difference in the immunofluorescence staining was observed between the intact and deafferented medial Vestibular Nuclei of lesioned animals or between the Vestibular Nuclei of lesioned and controls rats. Thus, deafferentation of the Vestibular Nuclei did not affect the expression of gephyrin, of the various GLYR subunits, or of their mRNAs in the deafferented and intact medial Vestibular Nuclei. It is therefore unlikely that GLYR and gephyrin modulation contribute significantly to the recovery of the resting discharge of the deafferented medial Vestibular neurons and consequently to the restoration of a normal posture and eye position.
-
glur2 r4 ampa subunit study in rat Vestibular Nuclei after unilateral labyrinthectomy an in situ and immunohistochemical study
Neuroscience, 2002Co-Authors: G Rabbath, Isabelle Vassias, P P Vidal, C De WaeleAbstract:Abstract In the present investigation, we address the question of whether the expression of GluR2–R4 subunits mRNAs and GluR2 and GluR4 subunits protein of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-selective glutamate receptors are modulated in the Vestibular Nuclei following unilateral labyrinthectomy. Specific GluR2–R4 radioactive oligonucleotides were used to probe sections of rat Vestibular Nuclei according to in situ hybridization methods. The signal was detected by means of film or emulsion photography. GluR2 and GluR4 subunit expression were also measured in control and operated rats by use of specific monoclonal GluR2 and GluR4 antibodies. Animals were killed at different stages following the lesion: 1, 3 or 8 days for the in situ hybridization study and 4 and 8 days for the immunohistochemical study. In normal animals, several brainstem regions including the lateral, medial, superior and inferior Vestibular Nuclei expressed all the GluR2, GluR3 and GluR4 subunit mRNAs. Moreover, numerous Vestibular Nuclei neurons are endowed with AMPA receptors containing the GluR2 and the GluR4 subunits. In unilaterally labyrinthectomized rats, no asymmetry could be detected on autoradiographs between the two medial Vestibular Nuclei probed with the GluR2 and the GluR4 oligonucleotide probes regardless of the delay following the lesion. However, compared to control, a bilateral decrease (−22%) in GluR3 gene expression was observed in the medial Vestibular Nuclei 3 days after the lesion followed by a return to normal at day 8 post-lesion. No significant asymmetrical changes in the density of GluR2- and GluR4-immunopositive cells could be detected between the intact and deafferented sides in any part of the Vestibular nuclear complex and at any times (day 4 or day 8) following the lesion. Our data show that the removal of glutamatergic Vestibular input induced an absence of modulation of GluR2 and GluR4 gene and subunits expression. This demonstrates that GluR2 and GluR4 expression do not play a role in the recovery of the resting discharge of the deafferented medial Vestibular Nuclei neurons and consequently in the functional restoration of the static postural and oculomotor deficits. The functional role of the slight and bilateral GluR3 mRNA decrease in the Vestibular Nuclei remains to be elucidated.
