胃动素对大鼠胃平滑肌细胞收缩活动的作用

EFFECT OF MOTILIN ON CONTRACTILE ACTIVITY OF ISOLATED SMOOTH MUSCLE OF STOMACH

本研究用大鼠游离的胃平滑肌细胞，观察胃动素对胃平滑肌细胞的收缩作用。结果表明：（１）胃动素明显增强单个胃平滑肌细胞收缩活动，在生理剂量１０（－１１）─１０（－１０）ｍｏｌ范围内，呈剂量依赖性。（２）不同胃分区平滑肌细胞对冒动素兴奋反应不同，胃动素对胃窦平滑肌细胞收缩强度大于胃体和幽门。（３）给予抗胃动素血清可以完全取消胃动素对胃肌细胞的收缩反应，而阿托品、ＴＴＸ、甲氰米胍、ｌｏｘｉｇｌｕｍｉｄｅ均不影响胃动素的作用。（４）给予胞内钙释放阻断剂ＴＭＢ－８可抑制胃动素对目肌细胞的收缩作用。上述结果提示，胃动素对胃平滑肌细胞的直接作用是由胃动素受体所介导，且与胞内Ｃａ（２＋）释放起重要作用。

The present study was conducted to investigate the contractile effect of motilin on isolated smooth muscle cells of rat stomach. The results were as follows: (1)Motilin elicited contraction of gastric smooth muscle cells in a dose-dependent manner from 10(-11) to 10(-10) mol. (2)At concentration of 10-10 mol, the contractile response of antral smooth muscle cells exceeded that of the body and pyrous muscle cells. (3)Anti-motilin serum could completely eliminate the stimulatory effect of motilin, which was not affected by atropine, TTX, cimetidine or loxiglumide. (4)TMB-8, an inhibitor of intracellular Ca2+ release, could also suppress completely the motilin effect.The above results suggested that the motilin effect on isolated gastric smooth muscle cells is a direct one, being mediated by highly specific motilin receptors in connection with the event of intracellular release of Ca(2+).