第四脑室给药对家兔呼吸和肾交感神经放电的影响

Effects of two drugs injected into the fourth ventricle on renal sympathetic nerve activity and phrenic muscle activity

目的 应用现代电生理学技术研究脑干交感中枢和呼吸中枢之间的关系。方法 在乌拉坦静脉麻醉和自主呼吸条件下 ,记录肾交感神经放电和膈肌肌电 ,观察第四脑室注射尼可刹米和吗啡对家兔呼吸、交感神经放电的影响。结果 与对照组相比 ,注射尼可刹米可引起呼吸呈浅快型 ,肾交感神经放电的积分幅度升高 (P <0 0 1 )和其呼吸节律更加明显 ;注射吗啡可导致呼吸呈浅慢型 ,肾交感神经放电的积分幅度明显升高 (P <0 0 1 ) ,交感神经的呼吸节律性放电频率变化与呼吸频率变化一致。结论 脑干呼吸中枢和交感中枢间存在着重要的神经联合结构 ,交感活动的呼吸节律源于呼吸中枢。

Objective To study the relation between sympathetic center and respiratory center.Methods Experiments were carried out on 30 adult rabbits of both sexes which were anesthetized with urethan and were spontaneous breathing.Efferent renal sympathetic nerve (RSA) and phrenic muscle activities were recorded as observed indexes.Blood pressure and end-tidal CO 2 concentration were instantly monitored.Rectal temperature usually was maintained between 37 and 38 in terms of Centigrad.Results 1.Nikethamide made RSA remarkably increase,the amplitude of integrated phrenic muscle activity decrease and respiratory rate increase.We noted that respiratory rhythmic discharge frequency of RSA was the same and synchronous with the respiratory rate.2. Morphine resulted in a enhancement of RSA following depressed breathing.The respiratory rhythmic discharge of RSA was always locked in a 1∶1 relation with the phrenic activity.Conclusions Experiment results show that changes of respiratory patterns can influence RSA distinctly.The observations show the existence of important synaptic connections between respiratory and vasomotor centers.Respiratory grouping of RSA derives from irradiation of the respiratory activity onto the brainstem system regulating sympathetic outflow.