【摘要】 目的　探讨槟榔碱 (Arecoline,Are)对大鼠门静脉和钙通道电流 (ICa)的剂量与效应的关系 ,阐明 Are灭螺增效的作用机制。　方法　采用离体大鼠门静脉自发性收缩活动的实验方法和全细胞膜片钳记录技术 ,研究 Are的剂量与效应关系 ,及其对 Ca2 +和 ICa的影响。　结果　不同浓度的 Are对大鼠门静脉的收缩力呈双相反应。 10 - 7～ 3× 10 - 7mol/LAre使门静脉的收缩力增强 ;10 - 6～ 10 - 4 mol/L 则使收缩力逐渐抑制 ,均呈浓度依赖性。Are3× 10 - 8～ 10 - 4 mol/L 对单个心室肌细胞钙通道电流的作用与门静脉一致 ,亦呈浓度依赖性的双相反应。门静脉收缩活动和全细胞记录钙通道电流的结果证明 ,不同浓度的 Are对 Ca2 + 和 ICa均显示有剂量与效应关系 ,低浓度有促 Ca2 + 及增加 ICa作用 ,高浓度有阻 Ca2 +内流及降低 ICa作用。　结论　阻钙作用可能是 Are降低钉螺上爬附壁率、灭螺增效作用的理论依据。更多还原

【Abstract】 Objective To investigate the concentration-effect relationship of Arecoline (Are) on rat portal vein and calcium current(I Ca), and to elucidate the oncomelania-killing machanism of Are. Methods Spontaneous contractive activities of isolated rat portal vein method and whole-cell patch clamp techniques were used to study the concentration-effect relationship of Are on calcium ion and I Ca. Results Are of different concentration showed a biphasic effect on the contractility of rat portal vein. At 10 -7-3×10 -7 mol/L it increased the contractility of rat portal vein, while at 10 -6-10 -4 mol/L it inhibited the contractility gradually, both in a concentration-dependent manner. Are 3×10 -8-10 -4 mol/L showed a concentration-dependent biphasic effect on calcium channel current of single ventricular myocyte, which were consistent with the effect on portal vein. Conclusion Results of Are on contractive activities of portal vein and I Ca proved that Are shows concentration-effect relationship on both calcium ion and I Ca. It promoted calcium influx and increased I Ca in low concentration, while inhibited calcium influx and reduced I Ca in high concentration. The inhibition effect of Are on I Ca might be the theoretical basis of climbing adhesion rate decreasing and snail-killing effects.更多还原