胃动素对大鼠胃平滑肌细胞收缩活动的作用

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。

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

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 ).