Open AccessPrompt Effect of Progesterone on the Adrenergic Response of Smooth Muscles
Author(s) -
Shigeru Morishita
Publication year - 1986
Publication title -
japanese journal of pharmacology/japanese journal of pharmacology
Language(s) - English
Resource type - Journals
eISSN - 1347-3506
pISSN - 0021-5198
DOI - 10.1254/jjp.42.289
Subject(s) - medicine , endocrinology , vas deferens , uterus , contraction (grammar) , guinea pig , depolarization , myometrium , taenia coli , receptor , epinephrine , uterine contraction , muscle contraction , adrenergic receptor , chemistry , biology
The contractile effects of epinephrine on the uterus and ductus deferens of the rabbit and the ductus deferens of the monkey were inhibited by the preincubation with progesterone (6.4 X 10(-5) M) for 1 or 3 min in Locke-Ringer solution. Epinephrine relaxed the guinea pig uterus and taenia caecum. The relaxant effects were enhanced by preincubation with progesterone. Their effects were in a dose-dependent manner. There was no apparent change in the number and affinity of alpha-adrenergic receptors in the uterus of rabbits and the ductus deferens of guinea pigs during the incubation with progesterone. Progesterone has no direct effect on alpha-adrenergic receptors. All smooth muscles yielded reproducible contractile reactions to Ca2+ when maintained in depolarizing Tyrode's solution containing K+ (40 mmol/l). Their concentration-response curves were inhibited by preincubation with progesterone (6.4 X 10(-5) M), and they were shifted to the right in a concentration-dependent manner. Established Ca2+-induced contractions were rapidly relaxed by the addition of progesterone (6.4 X 10(-5) M). It suggests that progesterone directly affects the plasma membrane and inhibits the voltage-dependent Ca2+ channel and then inhibits smooth muscle contraction.