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γ-氨基丁酸对离体大鼠延髓头端腹外侧区神经元单位放电的抑制作用

储祥平, 李鹏, 徐宁善

上海医科大学生理学教研室

摘要

在73张脑片上观察了γ-氨基丁酸（GABA）对106个延髓头端腹外侧区（RVLM）神经元单位放电的影响。外源性的GABA（0．1－3．0mmol／L）抑制了106神经元中的84个神经元的电活动，这些抑制效应呈剂量-反应关系。GABA的抑制效应大部分可被GABAA受体选择性拮抗剂荷苞牡丹碱甲基碘化物（BMI）和Cl-通道阻断剂印防己毒素（PTX）所阻断，而单独灌流BMI和PTX对RVLM神经元主要起兴奋作用。在41个对GABA有抑制效应的RVLM神经元上，GABAB受体选择性激动剂苯氯丁氨酸（0．1－3．0μmnol／L）抑制了其中33个神经元的单位放电，也呈剂量-反应关系。GABAB受体选择性拮抗剂CGP35348（n＝13）可阻断苯氯丁氨酸的抑制效应（n＝21），而单独灌流CGP35348对RVLM神经元主要起兴奋作用。上述结果提示：GABA对RVLM神经元的抑制效应，不仅可以通过GABAA受体，而且可以通过GABAB受体起作用；内源性的GABA参与了紧张性的抑制作用。

关键词： γ-氨基丁酸; γ-氨基丁酸受体; 单位放电; 延髓头端腹外侧区; 延髓脑片

Cui Hong

First Clinical Institute，China Medical University. Shenyang 110001,Liaoning, China

Abstract

Extracellular single-unit discharges were obtained from 106 spontaneously active neurons inthe region of the rostral ventrolateral medulla (RVLM) by glass microelectrode from 73 brain slices of SpragueDawley rats. Exogenous γ-aminobutyric acid (GABA, 0. 1 ~3.0 mmol/L) inhibited the electrical activity of84 out of 106 RVLM neurons dose-dependently. The inhibitory effect of GABA could be blocked by GABAAreceptor antagonist bicuculline bicuculline methiodide (BMI) and Cl- channel blocker picrotokin (PTX). When perfusedwith BMI or PTX alone, the firing rates of most of the RVLM neurons were significantly increased. In 41neurons responding to GABA, baclofen (0. 1 ~ 3.0 μmol/L), a GABAB receptor selective agonist, inhibitedthe discharges of 33 of the neurons dose-dependently. GABAB receptor antagonist CGP35348 (n = 13) blockedthe inhibition due to baclofen (n = 21 ). After perfused with CGP35348 alone, the firing rates of most of theRVLM neurons were significantly increased.

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引用本文：

储祥平, 李鹏, 徐宁善. γ-氨基丁酸对离体大鼠延髓头端腹外侧区神经元单位放电的抑制作用 [J]. 生理学报 1998; 50 (5): .

Cui Hong. . Acta Physiol Sin 1998; 50 (5): (in Chinese with English abstract).