细胞内钙离子对肛门内括约肌收缩作用的实验研究

THE ROLE OF INTRACELLULAR CALCIUM IN THE CONTRACTIONS OF INTERNAL ANAL SPHINCTER

通过观察离体结肠平滑肌及肛门内括约肌在有／无钙离子的溶液中对乙酰胆硷及去甲肾上腺素的反应，以探讨细胞内钙离子对肛门内括约肌的收缩作用。结果：结肠平滑肌的激动剂是乙酰胆碱，而肛门内括约肌的激动剂则是去甲肾上腺素。在无钙溶液中结肠平滑肌的收缩受到明显抑制（Ｐ＜０．０１），而肛门内括约肌的收缩未受明显影响；能使细胞内钙离子库耗竭的药物兰诺丁（ｒｙａｎｏｄｉｎｅ）对结肠平滑肌的收缩无影响，而肛门内括约肌的收缩则受到显著抑制（Ｐ＜０．０１）。本实验结果提示：结肠平滑肌的收缩主要与细胞外钙离子的内流有关；

From this experiment we found that acetylcholine (Ach) was the agonist of the colonic smooth muscles, and noradrenaline (NA) the internal anal sphincter(IAS). The contractions of colonic smooth muscles were significantly inhibited under the calcium free solution ( P <0.01), but the IAS was not affected. Ryanodine, which can exhaust the intracellular calcium, remarkably depressed the contractions of IAS ( P <0.01),but had no effect on the colonic smooth muscles. It can be concluded that the contractions of colonic smooth muscles are mainly related to the influx of extracellular calcium; the release of intracellular calcium plays an important role in the contractions of IAS.