下丘脑腹内侧核区神经元的周期性活动

用玻璃微电极记录了乌拉坦麻醉并用三碘季铵酚麻痹的大鼠下丘脑腹内侧核区(HVM)及邻近脑区(室旁核,下丘脑前区,下丘脑前内侧核)的自发单位活动。在HVM区82个单位中有8个表现短周期性活动的单位。其中又可分为两类:(1)由活动相和沉默相相互交替的周期性活动;(2)逐渐作缓慢变化的周期性活动。每个周期的时间由1～5分钟不等。腹腔注射戊巴比妥钠后,周期性消失,,且平均放电率有所提高。这一结果提示HVM区神经元的周期性活动的抑制相不是该神经元固有的活动特征,而可能由神经元回路中的抑制作用所致。印防己毒素的效应很不一致。邻近HVM的其他脑区47个单位未发现周期性活动。

PERIODICITY OF NEURONAL DISCHARGE IN VENTROMEDIAL HYPOTHALAMIC NUCLEUS OF RAT

Unit discharges of neurons of the hypothalamic ventromedial nucleus region (HVM) and its surrounding structures including paraventricular nucleus, anterior hypothalamic area,and hypolhalamic dorsomcdial nucleus, were recorded in the ureth-ane-anesthetized and flaxidel-immobilized rats. In HVM,8 of 82 units showed periodical fluctuations in discharge rate, which could be categorized into two types: (1) With alternating active and silent phases 5 (2) with gradually waxing and waning phases. The duration of cach cycle varied from 1 to 5 minutes in different neurons. The periodicity disappeared after intraperitoneal injection of nembutal, while the average discharge rate was raised somewhat. This result suggested that the depressing pha-s of periodical activity of the HVM neuron might probably result from the inhibitory action in certain neuronal circuit, rather than from the intrinsic property of the recorded neurons. The effect of picrotoxin was contradictory. No periodical activity was noted in the 47 recorded neurons outside of the HVM.