刺激肾神经传入纤维的降压反应与颈动脉窦压力感受性反射的相互作用

在麻醉兔,研究了刺激肾神经传入纤维与颈动脉窦压力感受性反射在减压反射中的相互作用。电刺激肾神经传入纤维引起平均动脉压(MAP)下降,下降程度在一定范围有赖于刺激频率。当颈动脉窦被隔离和主动脉神经切断后,随着颈动脉窦内压逐渐升高,刺激肾神经传入纤维引起的减压反应不断减弱。在45至135mmHg 之间的7个颈动脉窦内压(ISP)水平,刺激肾神经传入纤维,并画出刺激前和刺激时的 ISP-MAP 关系曲线。在颈动脉窦内压为75至105mmHg 之间,刺激肾神经传入纤维显著降低 ISP-MAP 关系曲线的斜率和对ISP 的平均动脉压反应范围。这些结果提示:(1)颈动脉窦压力感受器的传入冲动可调制刺激肾神经传入纤维的降压反应,在一定范围内与颈动脉窦内压呈反比;(2)刺激肾神经传入纤维明显减弱颈动脉窦的压力感受性反射。

INTERACTION BETWEEN RENAL NERVE AFFERENT STIMULATION-PRODUCED DEPRESSOR RESPONSE AND CAROTIC SINUS BAROREFLEX

In anesthetized rabbits the fall in arterial blood pressure was dependent uponcertain voltage and frequency of stimulation of the peripheral end of the renal nerve.In rabbits with vascularly isolated carotid sinuses and aortic nerve cut,the depressorresponses to afferent stimulation of renal nerve were progressively diminished asintrasinus pressure(ISP)was elevated stepwise.At seven ISP levels between 45and 135 mmHg,mean arterial pressure(MAP)was plotted against ISP to obtainthe ISP-MAP relationship before and during afferent stimulation of renal nerve.Afferent stimulation of renal nerve significantly decreased the slope of ISP-MAPrelationship between 75 and 105 mmHg ISP and the range of ISP dependent MAP.These results suggest that(1)the depressor responses to afferent stimulation of renalnerve is modulated by carotid baroreceptor input,varying inversely with the ISPlevel;and(2)carotid sinus baroreflex sensitivity is greatly decreased by afferent stim-ulation of renal nerve.