Effects of ginkgolide B on neuronal discharges in paraventricular nucleus of rat hypothalamic slices  

银杏内酯B对大鼠下丘脑室旁核神经元自发放电的影响(英文)

作　　者：林悦[1] 王茹[1] 王昕[1] 何瑞荣[1] 武宇明[1] 

机构地区：[1]河北医科大学基础医学研究所生理室,石家庄050017

出　　处：《Neuroscience Bulletin》2008年第6期345-350,共6页神经科学通报（英文版）

摘　　要：Objective To study the central role of ginkgolide B （BN52021） in regulating cardiovascular function of nerve center by examining the effects of ginkgolide B on the electrical activity of rat paraventricular nucleus （PVN） neurons in hypothalamic slice preparation and to elucidate the mechanism involved. Methods Extracellular single-unit discharge recording technique. Results （1） In response to the application of ginkgolide t3 （0.1, 1, 10 μmol/L; n = 27） into the perfusate for 2 rain, the spontaneous discharge rates （SDR） of 26 （26/27, 96.30%） neurons were significantly decreased in a dose-dependent manner. （2） Pretreatment with L-glutamate （L-Glu, 0.2 mmol/L） led to a marked increase in the SDR of all 8 （100%） neurons in an epileptiform pattern. The increased discharges were suppressed significantly after ginkgolide B （1 μmol/L） was applied into the perfusate for 2 min. （3） In 8 neurons, perfusion of the selective L-type calcium channel agonist, Bay K 8644 （0.1 μmol/L）, induced a significant increase in the discharge rates of 8 （8/8, 100%） neurons, while ginkgolide B （1μmol/L） applied into the perfusate, could inhibit the discharges of 8 （100%） neurons. （4） In 8 neurons, the broad potassium channels blocker, tetraethylammonium （TEA, 1 mmol/L） completely blocked the inhibitory effect of ginkgolide B （1 μmol/L）. Conclusion These results suggest that ginkgolide B can inhibit the electrical activity of paraventricular neurons. The inhibitory effect may be related to the blockade of L-type voltage-activated calcium channel and potentially concerned with delayed rectifier potassium channel （KDR）.目的研究银杏内酯B(Ginkgolide B,BN52021)对静息状态下的下丘脑脑片室旁核神经元自发放电活动的影响。方法应用细胞外记录单位放电技术。结果(1)在27个下丘脑室旁核神经元放电单位给予银杏内酯B(0.1,1,10μmol/L)2分钟,有26个放电单位(96.30%)放电频率明显降低,且呈剂量依赖性;(2)预先用0.2mmol/L的L-glutamate(L-Glu)灌流下丘脑脑片,8个放电单位放电频率明显增加,表现为癫痫样放电,在此基础上灌流银杏内酯B(1μmol/L)2分钟,其癫痫样放电全部被抑制;(3)预先用L型钙通道开放剂BayK8644灌流8个下丘脑脑片,8个放电单位(100%)全部放电增加,在此基础上灌流银杏内酯B(1μmol/L)2分钟,8个放电单位(100%)放电频率明显减低;(4)在8个下丘脑室旁核神经元放电单位上,银杏内酯B(1μmol/L)的抑制效应可被广泛钾通道阻断剂(tetraethylammonium,TEA)1mmol/L完全阻断。结论银杏内酯B(Ginkgolide B,BN52021)可抑制下丘脑室旁核神经元自发放电,并可抑制由L-glutamate诱发的神经元放电。提示银杏内酯B对心血管中枢神经元通过降低其活动而具有一定程度的保护作用,这种作用可能与银杏内酯B抑制L型钙通道有关,而且可能与延迟整流型钾通道(delayed rectifier potassium channel,KDR)有关。

关 键 词：paraventricular hypothalamic nucleus ginkgolide B L-GLUTAMATE Bay K 8644 TEA 

分 类 号：R285.5[医药卫生—中药学]