头端延髓腹外侧区在躯体传入冲动抑制诱发压力感受性反射中的作用

A ROLE OF ROSTRAL VENTROLATERAL MEDULLA IN SOMATIC INPUT INHIBITION OF EVOKED BAROREFLEX

电刺激家兔主动脉神经(AN)诱发的压力感受性反射能明显地被低频低强度刺激腓浅神经(SPN)所阻断。头端两侧延髓腹外侧区(γVLM)微量注射阿托品可完全消除刺激SPN对诱发压力感受性反射的阻断效应。在脊髓高位横断后,两侧rVLM微量注射胆碱拟似剂和神经元胞体兴奋剂,对刺激AN诱发的心动过缓和降压反应也产生阻断效应。这些结果表明:在rVLM存在胆碱能机制参与躯体传入冲动对诱发压力感受性反射的抑制作用。

Experiment were performed on twenty -five adult rabbits anesthetized intravenously, paralyzed with Flaxedil and Ventilated artificially. A depressor response and brabycardia were elicited by aortic nerve (AN) stimulation. The evoked baroreflexes were dramatically e-voked by electrial stimulation of superficlial peroneal nerve (SPN) with low frequency and low intensity. Microinjection of atropine sulfate into the bilateral rostral ventrolateral medulla (RVLM)completey abolished the effects off SPN stimulation on the evoked brady-cardia and depresor response. In thespinal animals, application of both physostigmine and DL-ho-mocysteic acid into the same areas within bilateral RVLM also produced blocking effect on the AN stimulation - induced baroreflex. These results indicate that endogenous cholinergic mechanisms in the RVLM appear to the inhibitory effect of somatic input on the evoked baroreflexes.