兔腹部迷走神经、内脏大神经活动在孤束核中的相互作用

INTERACTION OF ABDOMINAL VAGUS AND GREATER SPLANCHNIC NERVE ACTIVITIES IN THE NUCLEUS TRACTUS SOLITARIUS OF THE RABBIT

本实验在67只家兔身上分别观察了电解损毁孤束核(NTS)前后刺激腹迷走神经和内脏大神经中枢端对血压的影响,以及刺激这两种神经中枢端对 NTS 神经元放电活动的影响。结果表明:来自腹迷走神经和内脏大神经的感觉冲动不仅都可以投射至 NTS,而且这两种传入冲动在 NTS 还存在着会聚现象。一种传入神经的阈下刺激(背景刺激)可以削弱另一传入神经的血压效应,一种传入神经的(背景刺激)可以抑制另一种神经元引起的 NTS 神经元电活动。本文对这两种传入冲动之间存在的相互作用关系的可能机制及意义进行了讨论。

Experiments were performed on 67 rabbits.Effects of stimulation of thecentral ends of abdominal vagus and greater splanchnic nerve on arterial bloodpressure before and after destruction of nucleus tractus solitarius(NTS)and theunit discharges in the NTS before destruction were observed.As a result,wesuggest that both the afferents coming from the abdominal vagus and greater splan-chnic nerve not only converge on NTS neurons but also interact with each other.Subthreshold stimulation elicited from one of the afferent fibers suppresses thearterial blood pressure responses caused by the other afferent.Similarly,back-ground stimulation elicited from one afferent can suppress the NTS unit dischargescaused by the other afferent.It is much easier for abdominal vagal afferent to in-hibit the NTS unit discharges and the arterial blood pressure changes elicited bystimulation of the splanchnic nerve.A possible mechanism of such relationshipwas discussed.