情前期与间情期大鼠内侧视前区-下丘脑前区神经元的电活动

在氯化筒箭毒制动的情前期及间情期大鼠上进行实验。用玻璃微电极记录内侧视前区-下丘脑前区(mPOA-AHA)的单位放电。mPOA-AHA 的大多数单位表现连续性或周期性自发放电。情前期大鼠周期性放电单位所占的百分比显著地多于间情期大鼠(P<0.01)。刺激子宫颈部可以使单位放电发生两种反应。一种单位对宫颈刺激发生放电频率增加的反应(宫颈兴奋神经元,CE 神经元),另一种单位则发生放电频率降低的反应(宫颈抑制神经元,CI神经元)。情前期大鼠 CE 与 CI 神经元所占的百分比与间情期大鼠没有明显的差异(P>0.05)。但情前期大鼠的 CE和 CI 神经元多呈现周期性放电,而间情期大鼠的 CE 和 CI 神经元则多呈现连续性放电。这说明 mPOA-AHA 神经元的电活动随生殖周期发生明显的变化。脑室注射去甲肾上腺素(NE)能使 mPOA-AHA 内大多数 CE 神经元对宫颈刺激的兴奋反应暂时受到抑制,而注射 NE 却使大多数 CI 神经元发生抑制解除。这些结果提示 NE 可能有抑制 CE 神经元和刺激 CI 神经元的作用。

UNIT ACTIVITIES IN THEDIAL PROPTIC-ANTERIOR HYPOTHALAMIC AREAS OF PROESTRUS AND DIESIRUS RATS

Unit discharges were recorded with glass microelectrodes in the medial preop-tic-anterior hypothalamic areas(mPOA-AHA)of proestrus and diestrus rats immo-bulized by d-tubocurarine.Most units showed spontaneous discharges either con-tinuously or in periodic pattern.In proestrus rats,the percentage of units dis-charged in periodic pattern was significantly higher than in diestrus rats(p<0.01).Unit discharges in response to stimulation of cervix of uterus may be classifiedinto two groups.One group showed definite increase(cervical excitatory neurons,CE neurons),while the other,a decrease in discharge frequency(cervical inhibi-tory neurons,CI neurons).Both CE and CI neurons are equally found in proes-trus and diestrus rats.But in proestrus rats.most CE and CI neurons exhibitedperiodic instead of continuous discharges as in diestrus rats.After intraventricular injection of norepinephrine(NE),excitatory responsesof most CE neurons in mPOA-AHA were temporarily inhibited.In contrast,ad-ministration of NE resulted in disinhibition in the majority of CI neurons.Fromthese results,it is suggested that NE might inhibit the CE neurons and stimulatethe CI neurons.