[Effects of prostaglandins on the contractile mechanism, especially on an intracellular Ca store in uterine smooth muscle cells].

The effects of prostaglandins were studied on the contractile activities in isolated myometrial or vaginal strips from humans and rats by recording isometric tension development. PGE2 decreased the contractility in corpus and cervix from non pregnant human uterus, but increased the contractility in corpus and decreased the contractility in cervix from term human uterus. PGF2 alpha increased the contractility in corpus and cervix from non pregnant and term human uterus. PGE2 increased the contractility in corpus, but decreased the contractility in cervix and vagina from non pregnant and term rats. PGF2 alpha increased the contractilities in corpus, cervix and vagina from non pregnant and term rats. The effects of prostaglandins were studied on an intracellular Ca store in the depolarized uterine smooth muscle cells from non pregnant rats. The activative effects on the contractile mechanism by prostaglandins supported the suggestion that prostaglandins have an activative action on Ca2+ influx and Ca2+ release from intracellular Ca store. The inhibitory effects on the contractile mechanism by PGE2 supported the suggestion that PGE2 have an inhibitory action on Ca2+ influx and Ca2+ release from intracellular Ca store.