东莨菪碱对大鼠离体室旁核神经元单位放电的影响

EFFECTS OF SCOPOLAMINE ON ELECTRIC ACTIVITY OF PARAVENTRICULAR NEURONS IN RAT HYPOTHALAMIC SLICES

目的为对东莨菪碱抗休克的机制作进一步分析，观察其对大鼠离体下丘脑室旁核神经元活动的影响。方法与结果在２５个大鼠下丘脑薄片上，用玻璃微电极记录了５５个室旁核神经元自发放电。其放电活动可分非周期型和周期型两类。当灌流含东莨菪碱（１０－７ｍｏｌ／Ｌ，３ｍｉｎ）的人工脑脊液后，在３２个非周期型放电单位中呈现增频反应的有５个（１５．６％），减频反应的１２个（３７．５％），１５个无反应（４６．９％）；７个周期型放电单位均无反应。同时也观察到，东莨菪碱对室旁核内被ＮＡ兴奋的神经元或被Ａｃｈ兴奋和抑制的神经元具有翻转作用。结论由α受体、Ｍ１和Ｍ２受体介导的室旁核神经元能分别被东莨菪碱所阻断。

The effects of scopolamine on the spontaneous discharge of 55 paraventricular neurons (PVN) in 25 rat hypothalamic slices were observed using extracellular microelectrode technique. It was found that PVN consisted of phasic-discharge and nonphasic-discharge neurons.In the 32 nonphasic ones, scopolamine perfusion (10-7mol/L,3min) caused significant increase of discharge rate in 5 neurons (5/32, 15.6%), decrease in 12 (37.5%) and no response in 15 (46.9%). But in none of the 7 phasic neurons, the discharge rate was altered by scopolamine perfusion. The excitatory effect of NA and the excitatory/inhibitory effects of Ach on the discharge rates could be reversed by scopolamine perfusion.These results suggest that the changes of electric activity of PVN mediated by αand M1 and M2 receptors can be antagonized by scopolamine separately through blockade of those receptors.