• PNF and Movement
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• 제4권1호
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• pp.51-62
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• 2006

Purpose : The purposes of this study were to test the effect of proprioceptive and vestibular sensory input on expression of BDNF after traumatic brain injury in the rat. Subject : The control group was sacrificed at 24 hours after traumatic brain injury. The experimental group I was housed in standard cage for 7 days. The experimental group II was housed in standard cage after intervention to proprioceptive and vestibular sensory(balance training) for 7 days. Method : Traumatic brain injury was induced by weight drop model and after operation they were housed in individual standard cages for 24 hours. After 7th day, rats were sacrificed and cryostat coronal sections were processed individual1y in goat polyclonal anti-BDNF antibody. The morphologic characteristics and the BDNF expression were investigated in injured hemisphere section and contralateral brain section from immunohistochemistry using light microscope. Result : The results of this experiment were as follows: 1. In control group, cell bodies in lateral nucleus of cerebellum, superior vestibular nucleus, purkinje cell layer of cerebellum and pontine nucleus changed morphologically. 2. The expression of BDNF in contralateral hemisphere of group II were revealed. 3. On 7th day after operation, immunohistochemical response of BDNF in lateral nucleus, superior vestibular nucleus, purkinje cell layer and pontine nucleus appeared in group II. Conclusion : The present results revealed that intervention to proprioceptive and vestibular sensory input is enhance expression of BDNF and it is useful in neuronal reorganization improvement after traumatic brain injury.

• Korean Journal of Acupuncture
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• 제25권3호
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• pp.117-135
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• 2008

Objectives: It is known that the vestibular imbalance leads to vestibular symptoms such as nausea, vomiting, vertigo and postural disturbance. Since the non-labyrinthine inputs from the limbs and viscera converge on the vestibular nucleus neurons receiving signal from peripheral vestibular endorgan, acupuncture to the periphery may influence the activities of vestibular nuclear neurons and produce a therapeutic effect on the vestibulacr symptoms. The present study was to examine a modification and characteristics of the static and dynamic activities of medial vestibular nucleus (MVN) neurons following electroacupuncture (EA) of GB43' acupoint. Methods: In 54 Sprague-Dawley adult male rats weighing 250${\sim}$300g, spontaneous firing discharges and dynamic responses induced by sinusoidal whole body rotation about vertical axis at 0.2 Hz were observed in MVN of rats during EA of GB43' acupoint, located between the left 4th and 5th toe, which is the territory of sural and peroneal nerves, with 0.2 ms, 40 Hz and 600${\pm}$200 ${\mu}A$. Results: EA of the left GB43' acupoint induced modifications of spontaneous firing rates in 45% of MVN neurons recorded, and the percentage of modified neurons was 44% in type I, 52% in type II and 46% in non-type neurons. The excitatory or inhibitory responses of spontaneous firing discharges were predominant in the ipsilateral MVN neurons during EA. The excitatory response was abolished after EA but the inhibitory response was prolonged after EA in the ipsilateral MVN. The neurons of MVN showing modified spontaneous firing discharges by EA showed lower frequency (${\geq}$10 spikes/sec) of mean spontaneous firing rates than non affected ones. Conclusion: These results suggest that the neuronal activities of MVN neurons were influenced by EA of GB43' acupoint and the effects of EA may be related to the convergence of the peripheral vestibular inputs and ascending somatosensory inputs on MVN.

• The Korean Journal of Physiology and Pharmacology
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• 제8권3호
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• pp.133-140
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• 2004

The purpose of the present study was to elucidate the possible involvement of the medial vestibular nucleus (MVN) and inferior vestibular nucleus (IVN) following acute hypotension in the vestibuloautonomic reflex through vestibulosolitary or vestibuloventrolateral projections. Acute hypotension-induced cFos expression was assessed in combination with retrograde cholera toxin B subunit (CTb) tract tracing. After injection of CTb into the solitary region, CTb-labeled neurons were located prominently around the lateral borders of the caudal MVN and medial border of the IVN. The superior vestibular nucleus also had a scattered distribution of CTb-labeled neurons. After injection of CTb toxin into the unilateral VLM, the distributions of CTb-labeled neurons in the MVN and IVN were similar to that observed after injection into the solitary region, although there were fewer CTb-labeled neurons. In the caudal MVN, about 38% and 13% of CTb-labeled neurons were double-labeled for cFos after injection of CTb into the solitary region and the VLM, respectively. In the IVN, 14% and 7% of CTb-labeled neurons were double-labeled for cFos after injection of CTb into the solitary region and the VLM, respectively. Therefore, the present study suggests that acute arterial hypotension may result in activation of vestibulosolitary pathways that mediate behavioral and visceral reflexes, and vestibuloventrolateral medullary pathways that indirectly mediate vestibulosympathetic responses.

• The Korean Journal of Physiology and Pharmacology
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• 제6권6호
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• pp.287-291
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• 2002

Intrinsic excitabilities of acutely isolated medial vestibular nucleus (MVN) neurons of rats with normal labyrinth and with undergoing vestibular compensation from 30 min to 24 h after unilateral vestibular deafferentation (UVD) were compared. In control rats, proportions of type A and B cells were 30 and 70%, respectively, however, the proportion of type A cells increased following UVD. Bursting discharge and irregular firing patterns were recorded from 2 to 12 h post UVD. The spontaneous discharge rate of neurons in the ipsilesional MVN increased significantly at 2 h post-UVD and remained high until 12 h post-UVD in both type A and type B cells. After-hyperpolarization (AHP) of the MVN neurons decreased significantly from 2 h post-UVD in both types of cells. These results suggest that the early stage of vestibular compensation after peripheral neurectomy is associated with an increase in intrinsic excitability due to reduction of AHP in MVN neurons.

• International Journal of Oral Biology
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• 제34권4호
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• pp.215-222
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• 2009

Medial vestibular nucleus (MVN) neurons are involved in the reflex control of the head and eyes, and in the recovery of vestibular function after the formation of peripheral vestibular lesions. In our present study, whole cell patch clamp recordings were carried out on MVN neurons in brainstem slices from neonatal rats to investigate the actions of a group I metabotropic glutamate receptor (mGluR) agonist upon synaptic transmission and ionic currents. Application of the mGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG) increased the frequency of miniature inhibitory postsynaptic currents (mIPSCs) but had no effect upon amplitude distributions. To then identify which of mGluR subtypes is responsible for the actions of DHPG in the MVN, we employed two novel subtype selective antagonists. (S)-(+)-$\alpha$-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist of mGluR5. Both LY367385 and MPEP antagonized the DHPG-induced increase of mIPSCs, with the former being more potent. DHPG was also found to induce an inward current, which can be enhanced under depolarized conditions. This DHPG-induced current was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed by the PLC blocker U-73122, the $IP_3$ receptor antagonist 2-APB, and following the depletion of the intracellular $Ca^{2+}$ pool by thapsigargin. These data suggest that the DHPG-induced inward current may be mainly regulated by the intracellular $Ca^{2+}$ store via the PLC-$IP_3$ pathway. In conclusion, mGluR I, via pre- and postsynaptic actions, may modulate the excitability of the MVN neurons.

• Research in Vestibular Science
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• 제17권4호
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• pp.142-151
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• 2018

Objectives: Excitability o medial vestibular nucleus (MVN) in the brainstem can be affected by changes in the arterial blood pressure. Several animal studies have demonstrated that acute hypotension results in the alteration of multiunit activities and expression of cFos protein in the MVN. In the field of extracellular electrophysiological recording, tetrode technology and spike sorting algorithms can easily identify single unit activity from multiunit activities in the brain. However, detailed properties of electrophysiological changes in single unit of the MVN during acute hypotension have been unknown. Methods: Therefore, we applied tetrode techniques and electrophysiological characterization methods to know the effect of acute hypotension on single unit activities of the MVN of rats. Results: Two or 3 types of unit could be classified according to the morphology of spikes and firing properties of neurons. Acute hypotension elicited 4 types of changes in spontaneous firing of single unit in the MVN. Most of these neurons showed excitatory responses for about within 1 minute after the induction of acute hypotension and then returned to the baseline activity 10 minutes after the injection of sodium nitroprusside. There was also gradual increase in spontaneous firing in some units. In contrast small proportion of units showed rapid reduction of firing rate just after acute hypotension. Conclusions: Therefore, application of tetrode technology and spike sorting algorithms is another method for the monitoring of electrical activity of vestibular nuclear during acute hypotension.

• PNF and Movement
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• 제5권1호
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• pp.9-17
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• 2007

Purpose : The purpose of this study was to test the effect of balance training for proprioceptive and vestibular sensory stimulation and therapeutic environment on expression of BDNF after traumatic brain injury in the rat. Subject : Twelve Sprague-Dawley rats were randomly assigned into group I and group II. After traumatic brain injury, group I was housed in standard cage for 7 days. Group II was housed in therapeutic cage after balance training for 7 days. Method : Traumatic brain injury was induced by weight drop model and after operation they were housed in individual standard cages for 24 hours. After 7th day, the rats were sacrificed and cryostat coronal sections were processed individually in goat polyclonal anti-BDNF antibody. The morphologic characteristics and the BDNF expression were investigated in injured hemisphere section from immunohistochemistry using light microscope. Result : Immunohistochemical response of BDNF in lateral nucleus, purkinje cell layer, superior vestibular nucleus and pontine nucleus appeared very higher in group II than in group I Conclusion : The present result revealed that simultaneously application of balance training for proprioceptive and vestibular sensory stimulation input and therapeutic environment in traumatic brain injured rats is enhance expression of BDNF and it is facilitates neural plasticity.

• The Korean Journal of Physiology and Pharmacology
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• 제7권2호
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• pp.59-63
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• 2003

The medial vestibular nucleus (MVN) neurons are controlled by excitatory synaptic transmission from the vestibular afferent and commissural projections, and by inhibitory transmission from interneurons. Spontaneous synaptic currents of MVN neurons were studied using whole cell patch clamp recording in slices prepared from 13- to 17-day-old rats. The spontaneous inhibitory postsynaptic currents (sIPSCs) were significantly reduced by the $GABA_A$ antagonist bicuculline ($20{\mu}M$), but were not affected by the glycine antagonist strychnine ($1{\mu}M$). The frequency, amplitude, and decay time constant of sIPSCs were $4.3{\pm}0.9$ Hz, $18.1{\pm}2.0$ pA, and $8.9{\pm}0.4$ ms, respectively. Spontaneous excitatory postsynaptic currents (sEPSCs) were mediated by non-NMDA and NMDA receptors. The specific AMPA receptor antagonist GYKI-52466 ($50{\mu}M$) completely blocked the non-NMDA mediated sEPSCs, indicating that they are mediated by an AMPA-preferring receptor. The AMPA mediated sEPSCs were characterized by low frequency ($1.5{\pm}0.4$ Hz), small amplitude ($13.9{\pm}1.9$ pA), and rapid decay kinetics ($2.8{\pm}0.2$ ms). The majority (15/21) displayed linear I-V relationships, suggesting the presence of GluR2-containing AMPA receptors. Only 35% of recorded MVN neurons showed NMDA mediated currents, which were characterized by small amplitude and low frequency. These results suggest that the MVN neurons receive excitatory inputs mediated by AMPA, but not kainate, and NMDA receptors, and inhibitory transmission mediated by $GABA_A$ receptors in neonatal rats.

• The Korean Journal of Physiology and Pharmacology
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• 제18권4호
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• pp.353-358
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• 2014

Control of blood pressure is maintained by the interaction between the arterial baroreflex and vestibulosympathetic reflex during postural changes. In this study, the contributions of vestibular receptors and baroreceptors to the maintenance of blood pressure following acute hypotension were compared in terms of phosphorylated extracellular regulated protein kinase (pERK) expression in the nucleus tractus solitaries (NTS). Expression of pERK in the NTS was measured in conscious rats that had undergone bilateral labyrinthectomy (BL) and/or sinoaortic denervation (SAD) 5, 10, 20, and 40 min following acute hypotension induced by sodium nitroprusside (SNP) infusion. Expression of pERK increased significantly in the NTS in the control group following SNP infusion, and the expression peaked at 10 min after SNP infusion. The number of pERK positive neurons increased following SNP infusion in BL, SAD, and BL+SAD groups, although the increase was smaller than in control group. The BL group showed a relatively higher reduction in pERK expression than the SAD group, and the pERK expression in the NTS was localized to the caudal portion of the nuclei in the BL and SAD groups. These results suggest that the vestibular receptors may play a key role in maintaining blood pressure following acute hypotension; thus, the vestibular system may contribute to compensate for orthostatic hypotension.

• The Korean Journal of Physiology and Pharmacology
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• 제6권4호
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• pp.193-197
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• 2002

In spite of abundant anatomical evidences for the fiber connection between vestibular nuclei and inferior olivary (IO) complex, the transmission of vestibular information through the vestibulo- olivo-cerebellar climbing fiber pathway has not been physiologically established. The aims of the present study were to investigate whether there are IO neurons specifically responding to horizontal rotation and also in which subregions of IO complex these vestibularly-activated neurons are located. The extracellular recording was made in 68 IO neurons and responses of 46 vestibularly-activated cells were analyzed. Most of the vestibularly-activated IO neurons responded to signals of vertical rotation (roll), while a small number (13/46) of recorded cells were activated by horizontal canal signal (yaw). Regardless of yaw-sensitive or roll-sensitive, vestibular IO neurons were excited, when the animal was rotated to the side contralateral to the recording side. The gain and excitation phase were very similar to otolithic or vertical-canal responses. Histologic identification of recording sites showed that most of vestibular IO neurons were located in ${\beta}$ subnucleus. Electrical stimulation of a HSC evoked an inhibitory effect on the excitability of the ipsilateral IO neurons. These results suggest that IO neurons mainly in the ${\beta}$ subnucleus receive vestibular signals from semicircular canals and otolithic organs, encode them, and transmit vestibular information to the cerebellum.