夏天无总碱对钙拮抗作用的研究

Study of Antagonistic Effect of Total Alkaloids of Corydalis Amabilis Migo on Calcium

实验证实夏天无总碱(COAMTA)能舒张已为去甲肾上腺素(NE)、高K^+和CaCl_2引起收缩的兔胸主动脉条,使NE,KCl,CaCl_2的累积量-效曲线右移,最大效应降低,PD′_2分别为4.78、4.61和4.45。5×10^(-5)g COAMTA在离体心脏实验中可减弱心肌收缩力,但不影响心率和冠脉流量;还可明显拮抗由2×10^(-5)g CaCl_2所引起的心肌收缩力增强的效应;此外可显著延长血浆复钙时间。实验提示,COAMTA松弛血管平滑肌的作用是通过抗Ca^(++)

Corydalis amabilis Migo total alkaloids (COAMTA)has been demonstrated to dilate the isolated rabbit aortic strips which were in contraction evoked by NE, high K and CaCl_2. The cumulative dose-response curves for NE, KCl and CaCl_2 shifted to the right, and their maximal responses were depressed, The PD'_2 were 4.78, 4.61 and 4.45 respectively. COAMTA inhibited both fast and transitory contraction (Ca_1^(++)-dependent) response evoked by NE in Ca^(++)-free medium and the slow sustained contraction (Ca_0^(++)-dependent) response after the supplement of CaCl_2. In the isolated rabbit hearts, 5×10^(-5)g COAMTA showed negative inotropic effect and antagonized the positive inotropic effect of 2×10^(-5)g GaCl_2, so it further proved COAMTA antagonized the action of Ca^(++). In addition, COAMTA prolonged the time of rabbit plasma calcium recovery. These results suggested that COAMTA induced relaxation on vascular smooth muscle might result from its antagonistic effect to Ca^(++) and that the mode of this antagonism differed from that of Ver. It is possible that these 2 drugs interfere with 2 different transmembrane Ca^(++) channels.