[Role of cytosolic calcium release on gastrin induced contraction of gastric muscle cells of rat].

The present study was conducted to investigate the contractile effect of pentagastrin (G5) on isolated smooth muscle cells of rat stomach and role of cytosolic-free calcium ([Ca2+]i) release during contraction of gastric muscle cells induceed by G5. The results were as follows: (1) G5 induces contraction of smooth muscle cells isolated from gastric body, anturm and pylorus, in a dose-dependent manner from 4 x 10(-8) mol/L to 16 x 10(-8) mol/L, with the maximal effectiveness in antrum, (2) The action of G5 can be blocked by proglumide and anti-gastrin serum, but not by atropine. (3) The effect of acetylcholine and G5 are addtive when administrated simultaneously (4) Inhibitor of intracellular Ca2+ release TMB-8 could also suppress the G5 effect. (5) The effect of G5 could be seen accompaning significant increase of intracellular Ca2+ concentration. The above results suggested that the G5 induced contraction of gastric smooth muscle cells of rat is mediated via a distinct, specific type of receptors and cytosolic calcium release.