Ca2+ release-activated channels in rat stomach smooth muscle cells

In rat stomach fundus, contractions induced by Ca2+ (1.8 mM) were strikingly potentiated by thapsigargin. This potentiation was partially inhibited by the blockers of Ca2+ release activated channels (CRACs), miconazole and SK&F96365 ({1-[beta-[3-(4-methoxyphenyl)propoxy]-4- methoxyphenethyl]-1H-imidazole, HCL}) and slightly blocked by the antagonist of calcium voltage-operated channels (VOCs), isradipine. in dissociated cells in a 0Ca solution, thapsigargin potentiated the increase in intracellular calcium after reintroduction of Ca2+. This potentiation was partially reduced by the CRAC blockers, but not by the VOC blockers. This data suggests that calcium influx increased due to the depletion of intracellular calcium by thapsigargin and that this influx occurs predominantly through CRACs. (C) 1998 Elsevier Science B.V.Universidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, BR-04034060 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04034060 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, BR-04034060 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biophys, BR-04034060 São Paulo, BrazilWeb of Scienc