痛泻要方抑制大鼠离体结肠平滑肌收缩的钙动员机制

目的：从影响钙动员角度，探讨痛泻要方抑制大鼠结肠平滑肌收缩的作用机制。方法：应用离体平滑肌张力测定方法，观察痛泻要方对乙酰胆碱（acetylcholine, ACh）、氯化钾（KCl）和细胞内钙库耗竭后细胞外Ca^2＋内流引起的大鼠结肠平滑肌收缩的影响。结果：痛泻要方能够抑制KCl和细胞内钙库耗竭后细胞外Ca^2＋内流引起的大鼠结肠平滑肌收缩，并呈浓度依赖性。3 000 μg/mL 痛泻要方还能抑制ACh引起的第二收缩时相张力，与不加药的对照组（Krebs液）比较，差异有统计学意义（P〈0.01）；痛泻要方对ACh引起的第一收缩时相张力无明显影响。结论：痛泻要方主要通过抑制胞外Ca^2＋内流来抑制大鼠结肠平滑肌的收缩，可能涉及到阻断电压门控钙通道、钙库调控性钙通道和受体操纵性钙通道，但不影响ACh引起的胞内Ca^2＋释放。

Tongxie Yaofang inhibits the contraction of colonic smooth muscle isolated from rats through a mechanism related to calcium mobilization

Objective： To study the relationship between the inhibitory effects of Tongxie Yaofang, a compound traditional Chinese herbal medicine, on the contraction of the colonic smooth muscle isolated from rats and calcium mobilization.
Methods： By measuring the tension of the isolated colonic smooth muscle strips, the inhibitory effects of Tongxie Yaofang on the contraction induced by acetylcholine （ACh）, KCl and exhausting Ca2＋ of internal calcium store were assessed respectively.
Results： Tongxie Yaofang could concentration-dependently inhibit the contraction of isolated rat colonic smooth muscle strips induced by KCl and exhausting the Ca2＋ of internal calcium store. Tongxie Yaofang could also inhibit the tension of the second contractile phase induced by ACh （P〈0.01, vs control）, but had no influence on the first contractile phase.
Conclusion： Tongxie Yaofang can inhibit the contraction of isolated rat colonic smooth muscle strips mainly by preventing the influx of extracellular Ca^2＋, which may be associated with blocking voltage-dependent channel, store-operated channel and receptor-operated channel, but not by preventing the release of internal Ca2＋ from calcium store.