颈动脉窦内压的变化速率对反射性降压效应的影响

在成年狗身上制备右侧孤离颈动脉窦,借助灌流装置用饱和氧的任氏液对其进行灌流。灌流压为搏动性的。通过改变每搏泵出量、灌流管道的阻力和弹性来调节灌流压及其变化速率。用多导生理记录仪同步记录股动脉血压、窦内灌流压及其变化速率。本文主要观察窦内压的变化速率对降压反射的影响。在8只狗身上共进行了93次实验。结果表明,在窦内压相同的情况下,灌流压的上升速率愈快,降压效应愈明显,而其下降速率则无显著作用。已有资料证明搏动性窦内压所引起的降压效应较非搏动性压力更为明显。由此可见,狗的颈动脉窦压力感受器不仅对搏动性压力而且对其上升的变化速率也很敏感。

EFFCTS OF PRESSURE CHANGE RATE IN PERFUSION OF ISOLATED CAROTID SINUS ON DEPRESSOR REFLEX

The right carotid sinus was isolated from the systematic circulation in pentobarbital anaesthetized adult dogs. The sinus nerves were intact. The right common carotid artery was supplied with continuously oxygen saturated Ringer's solution by a pump. The perfusion pressure was pulsatile. The perfusion pressure and its change rate were adjusted by altering the pump output,the resistance of the outflow and elasticity of perfusion tubes.The blood pressure in femoral artery, carotid sinus pressure and its change rate were simultaneously recorded by a polygraph. The effects of pressure change rate in carotid sinus on depressor reflex was observed.Eight dogs were used as experimental subjects. The results showed that at the same pressure in carotid sinus, the more rapid the positive change rate of perfusion pressure, the more effective was the depressor reflex. However, the negative change rate of perfusion pressure acted no significant effct on depressor reflex.It is evident that the carotid sinus baroreceptors in dogs are sensitive not only to pulsatile pressure, but also to its positive change rate.