辣椒素对颈动脉窦压力感受性反射的易化作用(英文)

Capsaicin facilitates carotid sinus baroreflex in anesthetized rats

在30只隔离灌流颈动脉窦区的麻醉大鼠,观察了辣椒素(capsaicin,CAP)对颈动脉窦压力感受性反射的影响。结果显示(1)以CAP(1 μmol/L)隔离灌流大鼠左侧颈动脉窦区时,颈动脉窦压力感受性机能曲线向左下方移位,曲线最大斜率(peak slope,PS)由0.34±0.01增至0.42±0.01(P<0.01),反射性血压下降幅度(reflex decrease,RD)由36.51±1.26增至45.01±0.71 mmHg(尸<0.01)。阈压、平衡压和饱和压分别从70.43±2.09、95.5±1.71和177.60±1.37 mmHg下降至52.86±2.80、87.00±1.58、163.55±2.12 mmHg(P<0.01)。其中Ps和RD的变化呈明显的剂量依赖性。(2)用香草酸受体亚型(vanilloid receptor subtype 1,VR1)阻断剂钌红(ruthenium red,100 μmol/L)预处理后,CAP的上述反射效应即被阻断。(3)先给予KATP通道阻断剂格列苯脲(glibenclamide,20μmol/L)也取消了CAP对压力感受性反射的影响。结果表明,CAP对大鼠颈动脉窦压力感受性反射有易化作用,此作用似与VR.介导的KATP通道开放有关。

The effects of capsaicin (CAP) on the carotid sinus baroreflex were studied in 30 anaesthetized rats with perfused isolated carotid sinus. The results are as follows. (1) By perfusing the isolated carotid sinus with CAP (1μmol/L), the functional curve of the baroreflex was shifted to the left and downward, with a peak slope (PS) increasing from 0.34±0.01 to 0.42±0.01 (P<0.01), whereas the reflex decrease (RD) in mean arterial pressure was enhanced from 36.51±1.26 to 45.01±0.71 mmHg (P<0.01). Meanwhile, the threshold pressure, equilibrium pressure and saturation pressure were all significantly decreased from 70.43±2.09 to 52.86±2.80 mmHg (P<0.01), 95.5±1.71 to 87.00±1.58 mmHg (P<0.01) and 177.60±1.37 to 163.55±2.12 mmHg (P<0.01), respectively. Among the functional parameters of carotid baroreflex, the changes in PS and RD induced by capsaicin were dose-dependent. (2) By pretreatment with ruthenium red (RR, 100μmol/L), an antagonist of vanilloid receptor subtype 1 (VR,), the above effects of CAP on carotid baroreflex were abolished. (3) The CAP-induced change in the baroreflex was also eliminated by pretreatment with glibenclamide (20 μmol/L), a KATP channel blocker. On the basis of the results, it is concluded that CAP facilitates the carotid baroreflex, an effect of which may be resulted from the opening of KATp channels mediated by VR1'