刺激中缝背核观察尼莫地平及颈交感神经对家兔脑皮质微血流的影响

目的 :探讨电刺激兔中缝背核 (DRN)对家兔脑皮质微血流的影响及其机理。方法 :应用氢清除法测定局部脑组织血流 (rCBF)及观测软脑膜血管微循环。结果 :电刺激DRN后脑皮质rCBF减少 44 .2 % (P<0 .0 1) ,软脑膜微动脉管径缩小 ,血流速度减慢 ,而尼莫地平可取消其作用。切断颈交感神经后再刺激DRN ,rCBF减少 15 .8% (P <0 .0 5 )。结论 :电刺激DRN可导致脑皮质微动脉收缩 ,局部血流减少。尼莫地平可解除脑皮质微血管痉挛。切断颈交感神经有降低rCBF的作用。

Effect of Nimodipine and Cervical Sympathetic Nerve on Cerebral Cortical Microflow by Stimulating Dorsal Raphe Nucleus in Rabbits

Objective: To study the effect and its mechsanism of electrical stimulation of the dorsal raphe nucleus(DRN)on local blood flow(rCBF)of the parietal cortex in rabbit.Method: The hydrogen clearance method and the technique of determination of microcirculation of the pial vessels were applied.Results: Stimulation of DRN caused a significant decrease in rCBF by 44.29%( P<0.01 )and reduced the vessel diameter and blood flow velocity of the small pial arterioles.The influence of DRN stimulation on rCBF was inhibited by pretreatment of nimodipine.After acute bilateral sympathectomy stimulation of DRN only reduced by 15.8%( P<0.05 ).Conclusion: Activatition of the central serotonergic system may lead to cerebral vasoconstriction and reduce the microflow in the parietal cortex of the rabbit.