摘要
电刺激麻醉家兔延髓头端腹外侧区(rVLM)中的外侧网状核(R.1)、网状小细胞核(Rpc)与网状巨细胞核腹侧α部(Rgcα),均能诱发升压反应与室性期前收缩(VE),但各自所需的阈强度不同,其中以Rgcα所需阈强度最低,Rpc最高.在切断颈迷走神经的动物中,刺激腓深神经(DPN),能减弱刺激Rgcα诱发的升压反应;损毁中脑中央灰质腹侧部(vPAG)或按Sawyer图谱,在P5平面横断脑干,可消除DPN的这种抑制效应.以上结果提示:rVLM中不同核团对心血管活动的影响是有差异的,以Rgcα最易诱发升压反应与VE;DPN传入冲动能够部分地抑制以弱电流刺激Rgcα诱发的升压反应,这种抑制效应可能有赖于中脑头端以上区域某些脑结构的完整,vPAG可能是实现这种抑制的中枢环节之一.
The present study investigated the effect of electric stimulation of some major nuclei in rostral ventrolateral medulla(rVLM) on the cardiovascular function and the role of rVLM in the inhibition of central pressor response by some somatic nerve inputs in rabbits. Differences were detected in sensitivity of cardiovascular response evoked by electric stimulation of the pars α nuclei reticularis gigantocelularis (Rgcα), nucleus reticularis lateralis (R.1) and nucleus reticularis pavocelularis (Rpc). The thresholds were the lowerest in Rgcα-evoked pressor response and ventricular extrasystole but the highest in Rpc stimulation. There was no detectable cardiovascular response evoked by stimulation of nucleus nervi facialis with current at the intensity of 0.30-0.35mA. Stimulation of deep peroneal nerve (DPN) could reduce the pressor response elicited by rVLM stimulation in vagotomized rabbits. The inhibitory effect of DPN inputs could be abolished at the P5 levelled section of the brain stem or by electrolytic lesion of the ventral periaqueductal grey (vPAG). These results suggest that stimulation of Rgcα of rVLM in rabbits can be ready to evoke cardiovascular response and DPN inputs can reduce pressor response elicited by rVLM stimulation with low-intensity current. The inhibitory effect depends upon the integrity of vPAG in the midbrain and some brain structures above P5 level in rabbits.
基金
国家自然科学基金
关键词
延髓
病理生理学
心律失常
电疗法
Medulla oblongata/physiopathol
Postral ventrolateral medulla
Peroneal nerve
Arrhythmia/physiopathol
Blood pressure/physiopathol
Electrotherapy
