脊髓背柱在躯体传入冲动抑制中枢性升压反应的上行途径中的作用

目的:探讨脊髓背柱(DC)在躯体传入冲动对下丘脑室旁核(PVN)兴奋所致的心血管反应的抑制作用中的地位.方法:电刺激SD大鼠中枢核团PVN及对侧腓深神经(DPN),同时记录大鼠股动脉血压、平均动脉压(MAP)、心电图及心率(HR).急性损毁大鼠一侧背柱或损毁后存活5 d,观察DPN传入冲动对兴奋PVN诱发的心血管反应的影响及大鼠的痛反应、肌张力及屈肌反射等.结果:电刺激一侧PVN后,MAP升高,HR变化不一,以下降为主.刺激DPN对刺激PVN诱发的上述反应有抑制作用,MAP上升幅度由单独电刺激PVN时的(3.05±0.29)kPa降为(1.73±0.28)kPa,抑制百分比为43.29%.急性损毁右侧DC后,电刺激右侧或左侧DPN均能抑制刺激对侧PVN引起的升压效应,抑制百分比分别为38.64%和39.97%.左右侧DPN的抑制效应比较无显著差异(P>0.05).在6只损毁DC后5 d的大鼠,电刺激右侧或左侧DPN也均能抑制刺激对侧PVN引起的升压反应,抑制百分比分别为33.87%和36.86%.左右侧DPN的抑制效应比较无显著差异(P>0.05).损毁DC后大鼠双侧后肢痛反应无明显改变.结论:DPN抑制中枢性升压反应的上行传导途径不通过脊髓背柱.

Role of dorsal column in pathway of hypotensive effect of the somatic afferent inputs

Objective: To investigate the role of the dorsal column(DC) in the inhibitory effect of somatic afferent inputs on the central pressor response.Methods: The femoral arterial pressure,mean arterial pressure(MAP),electrocardiogram(ECG) and heart rate(HR) of the male SD rats were recorded when the hypothalamic paraventricular nucleus(PVN) was electrically stimulated with or without destruction of DC.The inhibitory effect of the deep peroneal nerve(DPN) on the pressor response induced by stimulation of PVN was observed 20 min or 5 d after ipsilateral DC destruction.Results: Stimulating DPN inhibited the pressor response elicited by electrical stimulation of PVN with an inhibitory rate of 43.29%.Twenty minutes after destroying the right DC,stimulation of the right or left DPN could inhibit the pressor response with an inhibitory rate of 38.64% and 39.97%,respectively(P>0.05);five days later the inhibitory rates remained as 33.87% and 36.86% respectively(P>0.05).The pain responses of both hindlimbs in the rats with the right DC destroyed showed no significant difference compared with the intact rats.Conclusion: DC is not involved in the inhibitory effect of DPN on the pressor response induced by PVN stimulation.