【摘要】 在麻醉大鼠隔离灌流颈动脉窦区条件下记录窦神经传入放电，观察内皮素（ET-1）对动脉压力感受器活动的影响。结果如下：（1）在颈动脉窦区灌流1nmol／LET-1时，压力感受器机能曲线向左上方移位，曲线的最大斜率（PS）增加，窦神经传入放电最大积分值（PIV）增大。由此提示，这一剂量的ET-1对压力感受器活动有易化作用。（2）用10nmol／LET-1灌流时，压力感受器机能曲线则向右下方移位，PS降低，PIV减小；100nmol／LET-1则使压力感受器机能曲线向右下方移位更为明显，PS及PIV降低更加明显。这些结果表明，上述两剂量的ET-1对压力感受器活动有抑制作用。（3）ETA受体选择性阻断剂BQ-123（0．15μmol／L）可阻断10nmol／LET-1对压力感受器活动的抑制效应。（4）预先灌流KATP通道阻断剂格列苯脲（10μmol／L），也可阻断ET-1的抑制效应。综上所述，ET－1对压力感受器活动有双重效应，低剂量时有易化作用，而较高剂量时则有抑制作用，后一作用由ETA型受体介导并有KATP通道的参与。更多还原

【Abstract】 The effects of endothelin (ET-1) on carotid baroreceptor activity were examined in33 anesthetized rats with perfused isolated carotid sinus by recolding sinus nerve afferentdischarge. The results obtained were as follows: (1) By perfusing with 1 nmol/L ET-1,the functional curve of carotid baroreceptor (FCCB) was shifted to the left and upwardwith increase of peak slope (PS), while the peak integral value of carotid sinus nervedischarge (PIV) was increased, indicating that the carotid baroreceptor activity wasfacilitated. (2) On the contrary, by perfusing with 10 nmol/L ET-1, FCCB was shiftedto the right and downward with a decrease of PS and PIV. In response to perfusion with100 nmol/L ET-1, FCCB was further shifted to the right and downward with a markeddecrease of PS and PIV. These results showed that ET-1 at 10 or 100 nmol/L exerted aninhibitory action on the baroreceptor activity. (3) Selective ETA receptor blocker-BQ-123(0.15 μmol/L) could abolish the inhibitory effects of ET-1 (10 nmol/L) onbaroreceptor. (4) Preperfusing with KATP channel antagonist-glibenclamide (10 μmol/L)could also eliminated the effects of ET-1. All the above results suggested that ET-1 exertsthe dual effects on baroreceptor, facilitation at low doses and inhibition at high doses.The later effect may be mediated by ERA bough KATP channels.更多还原