Influence of R-805 on the contractility and reactivity of rat myometrium.

It has been found that R-805 reduces and then eliminates the contractile activity of the isolated rat myometrium. R-805 weakens and then abolishes the reaction of the myometrium to polypeptides (oxytocin, vasopressin, bradykinin and hypertensin). In the presence of R-805, exogenous prostaglandin F(2) alpha restores the myometrial reactivity to the investigated polypeptides. On the basis of the obtained results and data from the literature a tentative hypothesis has been put forward as to the mechanism of R-805 action on the myometrial reactivity to polypeptides.