八肽胆囊收缩素和胃动素引起大鼠胃平滑肌细胞收缩的胞内钙、IP_3释放作用

The role of cystosolic calcium, IP_3 release in contraction of gastric muscle cells induced by CCK-8 and motilin in rats

目的和方法：本研究应用游离大鼠胃窦环行平滑肌细胞标本，分别观察八肽胆囊收缩素（CCK－8）和胃动素（motilin）对胃窦环行肌细胞收缩活动的作用，并同时测定胞内Ca2+与三磷肌醇（IP3）浓度的改变。结果：（1）CCK－8和胃动素均引起胃窦环行肌细胞收缩，CCK－8抗血清和CCKA受体阻断剂Loxiglumide，以及胃动素抗血清分别阻断了CCK－8和胃动素的作用；（2）CCK－8和自动素分别引起胃窦环肌细胞收缩的过程中，同时伴随胞内Ca2+与IP3浓度升高。结论：上述结果提示：（1）CCK－8和胃动素通过肌细胞膜表面的特异受体直接引起胃窦环肌细胞收缩；（2）CCK－8和胃动素引起胃窦环肌细胞收缩是由胞内Ca2+与IP3浓度升高引发。

Objectives and Methods: Isolated rat antral circular smooth muscle cells were used to investigate the action of CCK-8 and motilin with comcomitant mesurement of intracellular Ca2+and IP3 concentrations. Results: (1) Both CCK-8 and motilin caused contraction of antral circular muscle cells whereas CCK-8 antiserum; CCKA receptor antagonist Loxiglumide, motilin, antiserum blocked the action of CCK and motilin, respectively. (2) During the contraction of antral circular muscle cells and both intracellular Ca2+ and IP3 increased concomitantly. Conclusions: (1) Both CCK-8 and motilin, induced contraction of antral circular smooth muscle cells directly by binding to specific receptors on cell membrane; (2) The contractile effects of CCK-8 and motilin on gastric antral circular muscle cells are due to increase of intracellular Ca2+, which in turn depends upon the increase of intracellular IP3 content.