迷走神经对心血管活动的兴奋性影响

Excitatory Effects of Vagus on Cardiovascular Activity:A Review

迷走神经对心血管活动通常呈现抑制性影响,但许多动物实验观察证实,迷走神经对心血管活动还具有兴奋性影响,当刺激迷走神经外周端时,可看到血压升高,或在刺激停止后出现短时期的窦性心动过速,Copen等称之为迷走后加速(Postvagal tachycardia,PVT)。关于这种迷走心血管兴奋效应的机理,目前有以下一些认识:①乙酰胆硷对心肌有直接兴奋作用,②迷走神经的胆硷能效应,③迷走神经通过乙酰胆硷转而引起儿茶性胺释放的肾上腺素能机制。迷走心兴奋作用可能与临床所见心绞痛在晚间发作有关,是值得进一步研究的问题。

Vagus stimulation used to exhibit inhibitory effects on cardiovascular activity,but animal experiments showed that vagus stimulation has exci- tatory effects as well.When a distal end of vagus nerve was stimulated, one could find rise of blood pressure.or sinus tachycardia for a brief ti- me affter cessation of stimulation which was called by Copen et al.as postvagal tachycardia(PVT).Recently,explanation concerning the mechanis mof such excitatory effect of vagus has been considered to be:1.that ACh can stimulate myocardium cells sdtrectly,2.the cholinergic effect of vag- us,or 3.the adrenergic effect initiated by the release of CAT mediated by ACh via vagus.It is worth-While to carry out further investigation on the excitatory effects of vagus which may be related to the attack of angina pectoris at night found in clinics.