【摘要】 在麻醉大鼠观察了心房肽Ⅲ（AtriopeptinⅡ,APⅡ）对颈动脉窦压力感受器活动的影响,并在麻醉家兔观察了APⅡ作用于颈动脉窦区时窦神经传入放电的改变。结果如下:（1）用APⅡ（1μg/ml）隔离灌流大鼠左侧颈动脉窦区（n=10）,压力感受器反射的阈压（TP）无明显改变,平衡压（EP）由101±2.8降至95±2.0 mmHg（P<0.05）,饱和压（SP）由202±5.2降至168±6.1 mmHg（P<0.001）,而工作范围（OR）由128±5.5减至93±6.3mmHg（P<0.001）,压力感受器机能曲线向左下方移位,曲线最大斜率（PS）由0.77±0.04增大为1.07±0.13mmHg·mmHg^-1（P<0.05）;（2）在用硝普钠（NP,0.5μg/ml）灌流的动物（n=6）,TP和 EP 无改变,SP 由188±6.4升至218±6.0 mmHg（P<0.01）,OR 由107±6.9增至132±7.6 mmHg（P<0.05）,硝普钠对压力感受器机能曲线及其 PS 无显著影响;（3）恒压隔离灌流兔颈动脉窦区时,窦神经传入放电具有良好的稳定性,升高窦内压（ISP）时,窦神经传入放电也随之增多。用 APⅡ（1μg/ml）恒压灌流时,窦神经传入放电增加20.9±3.9%（n=6,P<0.01）,冲洗掉 APⅡ后,窦神经传入放电恢复至对照水平。以上结果显示,APⅢ可使大鼠颈动脉窦压力感受器机能曲线向左下方移位,曲线最大斜率增大以及兔窦神经传入放电增加,表明 APⅡ对颈动脉窦压力感受器活动有易化作用。这?更多还原

【Abstract】 Effects of atriopeptin Ⅲ(APⅢ)on the carotid sinus baroreflex in anesthe-tized rats and on the sinus nerve afferent activity in the anesthetized rabbits wereinvestigated.The results were as follows:(1)By perfusing the isolated left carotidsinus with AP Ⅲ(1 μg/ml)in anesthetized rats(n=10),the threshold pressure(TP)of the carotid baroreflex did not show any change,while the equilibriumpressure(EP),the saturation pressure(SP)and the operating range(OR)weredecreased from 101±2.8 to 95±2.0 mmHg(P<0.05),2.02±5.2 to 168±6.1mmHg(P<0. 001)and 128±5.5 to 93±6.3 mmHg(P<0.001),respectively.Thefunction curve of the baroreflex was shifted to the left and downward with a peakslope(PS)increased during perfusing with AP Ⅲ.In contrast,by perfusing thecarotid sinus with sodium nitroprusside(NP,0.5 μg/ml),TP and EP remainedunchanged,whereas SP and OR were increased from 188±6.4 to 218±6.0 mmHg(n=6,P<0.01)and from 107±6.9 to 132±7.6 mmHg(P<0.05),respectively.The function curve of the baroreflex and its PS were not affected by NP.The sinusnerve afferent activity was quite stable with the perfusion of carotid sinus at con-stant intrasinus pressure(ISP)in the rabbits(n=6)and increased during the ele-vation of ISP.By perfusing the carotid sinus with APⅢ(1 μg/ml)at constantISP,the integrated sinus nerve afferent activity was increased by 20.9±3.9%(P<0.01)and returned to the control level after washing out of AP 2ⅢThe results show that the carotid baroreceptor activity is facilitated by APⅢas evidenced by the shift of the baroreflex function curve to the left and downwardas well as the increase in the afferent activity of sinus nerve.Such an effect of APⅢis not likely to be attributed to its vasodilating action.It is proposed that the fa-cilitation of the carotid baroreceptor by APⅢ may be resulted from its direct ac-tion on barosensory endings.更多还原