• Research in Vestibular Science
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• v.17 no.4
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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.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.2
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• pp.85-89
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• 2003

The basic mechanism for the excitation of the peripheral vestibular receptors following acute hypotension induced by sodium nitroprusside (SNP) or hemorrhage was investigated in anesthetized rats. Electrical activity of the afferent vestibular nerve was measured after pretreatment with kynurenic acid, an NMDA receptor antagonist. The activity of the vestibular nerve at rest following acute hypotension induced by SNP or simulating hemorrhage was a greater increase than in control animals. The gain of the vestibular nerve with sinusoidal rotation following acute hypotension increased significantly compared to control animals. The acute hypotension induced by SNP or hemorrhage did not change the activity of the afferent vestibular nerve after kynurenic acid injection. These results suggest that acute hypotension produced excitation of the vestibular hair cells via glutamate excitotoxicity in response to ischemia.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.3
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• pp.275-281
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• 2015

Orthostatic hypotension is most common in elderly people, and its prevalence increases with age. Attenuation of the vestibulo-sympathetic reflex (VSR) is commonly associated with orthostatic hypotension. In this study, we investigated the role of glutamate on the vestibulo-solitary projection of the VSR pathway to clarify the pathophysiology of orthostatic hypotension. Blood pressure and expression of both pERK and c-Fos protein were evaluated in the nucleus tractus solitarius (NTS) after microinjection of glutamate into the medial vestibular nucleus (MVN) in conscious rats with sodium nitroprusside (SNP)-induced hypotension that received baroreceptor unloading via sinoaortic denervation (SAD). SNP-induced hypotension increased the expression of both pERK and c-Fos protein in the NTS, which was abolished by pretreatment with glutamate receptor antagonists (MK801 or CNQX) in the MVN. Microinjection of glutamate receptor agonists (NMDA or AMPA) into the MVN increased the expression of both pERK and c-Fos protein in the NTS without causing changes in blood pressure. These results indicate that both NMDA and AMPA receptors play a significant role in the vestibulo-solitary projection of the VSR pathway for maintaining blood pressure, and that glutamatergic transmission in this projection might play a key role in the pathophysiology of orthostatic hypotension.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.345-351
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• 1998

The role of nitric oxide (NO) in the hemorrhagic hypotension was examined using a NO synthase inhibitor, $N^{\omega}-nitro-L-arginine$ methyl ester (L-NAME), in conscious rats. The rats were bled at a constant rate (2 ml/kg/min) through a femoral arterial catheter until the mean arterial pressure (MAP) was reduced by 50 mmHg. We studied the responses to hemorrhage under normal condition (Control) and after the pretreatment with 3 doses of L-NAME (1.6, 8, 40 mg/kg i.v. of NOX1.6, NOX8, and NOX40, respectively). Intravenous bolus injection of L-NAME produced a sustained increase in MAP and decrease in heart rate (HR). During hemorrhage, the MAP fell faster in the NOX8 and NOX40-treated groups than in Control group, but the control group showed same response to NOX1.6. HR greatly increased in NOX groups. The recovery from hemorrhagic hypotension was slowed in the control group, which was not treated with L-NAME. In comparison with the control group, NOX8 and NOX1.6-treated groups registered a significant recovery in MAP during the 15 min recovery period, but NOX40 brought about only a slight increase in MAP. NO precursor, L-arginine (150 mg/kg i.v.), produced significant bradycardic responses before and after hemorrhage and significant depressor response only after hemorrhagic hypotension regardless of pretreatment with L-NAME. These data suggest that the role of NO in blood pressure regulation is greater after hemorrhagic hypotension than basal condition, but the effect of NO can be detrimental to the recovery from hemorrhagic hypotension. In addition, the bradycardic response of L-arginine provides indirect evidence that NO may inhibit sympathetic activity, especially after hemorrhagic hypotension.

• The Journal of Internal Korean Medicine
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• v.44 no.3
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• pp.544-554
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• 2023

Background: Postural hypotension refers to a drop in systolic blood pressure of 20 mmHg or diastolic blood pressure of 10 mmHg or more within three minutes after standing up from lying down. Symptoms of postural hypotension not only include dizziness and blurred vision but also fatigue, cognitive decline, leg weakness, headache, and, in severe cases, fainting. Postural hypotension is a phenomenon that occurs in about 6% of the total population, and in Korea, the number of patients with postural hypotension is continuously increasing. Both pharmacological and non-drug therapies, which are treatment methods for this disease, do not show a satisfactory symptom improvement effect. Case summary: A 65-year-old male patient who visited the hospital complaining of dizziness and paresthesia due to postural hypotension was treated with acupuncture, moxibustion, and herbal medicine. For symptom evaluation, the numeric rating scale (NRS) of each symptom was used, and blood pressure change according to posture was measured. After treatment, the NRSs of dizziness and dysesthesia were decreased, and blood pressure changes according to posture was improved. Conclusion: This case report suggests that Korean medicine treatment, including acupuncture, electro-acupuncture, moxibustion, and herbal medicine, can be an effective treatment for dizziness with postural hypotension.

• The Korean Journal of Pain
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• v.10 no.1
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• pp.104-108
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• 1997

Spontaneous intracranial hypotension, a syndrome of low CSF pressure, occurs without preceding events such as lumbar puncture, back trauma, operative procedure or medical illness. The most characteristic symptom is an occipital or frontal headache which is aggrevated in the erect position and relieved in the supine position. This syndrome usually resolves spontaneously or with strict bed rest. When the headach persists or is incapacitating, more aggressive treatment may be necessary. Autologous epidural blood patch is highly effective in the management of spontaneous intracranial hypotension. Epidural blood produces an organized clot which effectively tamponade any dural CSF leak. The rapid relief of headache immediately after the infusion of blood occur by some other mechanism, such as an increase in subarachnoid pressure that is known to occur with infusion of fluid into the lumbar epidural space. We report three cases of spontaneous intracranial hypotension successfully treated with epidural blood patch.

• Journal of Korean Neurosurgical Society
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• v.52 no.3
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• pp.254-256
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• 2012

Intracranial hypotension syndrome typically occurs spontaneously or iatrogenically. It can be associated with headache, drowsy mentality and intracranial heamorrhage, Iatrogenic intracranial hypotension can occur due to dural pucture, trauma and spine surgery. Treatment may include conservative therapy and operation. We report a case of a 54-year-old man who was successfully treated with epidural blood patches for intracranial hypotension due to cerebrospinal fluid (CSF) leakage into the lumbosacral area after spine surgery.

• The Korean Journal of Pain
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• v.13 no.1
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• pp.79-83
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• 2000

Background: Spontaneous intracranial hypotension is a syndrome characterized by postural headache without trauma, spinal anesthesia or other medical history. The purpose of this study is to analyze the effect of epidural blood patch in spontaneous intracranial hypotension. Methods: The spontaneous intracranial hypotension patients treated with epidural blood patch were analyzed on the symptoms, radiologic images and methods of epidural blood patch retrospectively by the medical records. Results: Patients had postural headache (15 patients) including nausea/vomiting (10 patients), tinnitus (2 patients), neck stiffness (13 patients), vertigo (3 patients) and occular pain (1 patient). Brain CT and MRI showed diffuse enhancement of the pachymeninges (9 patients) and radionuclide cisternography demonstrated direct evidence of leakage (11 patients). With epidural blood patch, the symptoms were promptly relieved in 11 patients. Conclusions: We concluded that epidural blood patch is a good treatment of method in spontaneous intracranial hypotension patients.

• Journal of Oriental Medical Thermology
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• v.2 no.1
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• pp.29-34
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• 2003

Purpose The purpose of this study was to verify the association between Cold Hypersensitivity and Orthostatic Hypotension(OH). Method This study was carried out on 39 women who visited outpatient department of Dept. of Gynecology. Bundang CHA oriental Hospital. College of Medicine. Pochun CHA univ. from December 2001 to November 2002. We divided them into two groups (Orthostatic Hypotension Group 24, Normal BP Group 15) and investigated general characteristics, weight, height, past history. family history through out the patient's note. OH was assessed 1 minute after the patients rose from a supine position by using tilting table. For the diagnosis of cold hypersensitivity, thermographic measurements were performed on two pairs of areas(palm-upper arm and back of hand-upper arm. And for that of the feet, other two pairs of areas(anterior thigh-top of the feet and posterior thigh-heel). And then by which verify the association between Cold Hypersensitivity and Orthostatic Hypotension(OH) Results As a results, 16 out of 24 patients, the OH group had cold hypersensitivity and 4 out of 15 Patients the normal BP group had cold hypersensitivity. It means that there was association between Cold Hypersensitivity and Orthostatic Hypotension(OH). Conclusion Above these results, we can reach the conclusion that OH is considered one of the causes of cold hypersensitivity.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.4
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• pp.199-205
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• 2002

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, $15{\mu}g/kg$ 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.