EFFECT OF ISOPROTERENOL ON THE ISOLATED PREGNANT RAT MYOMETRIUM

In pregnant rat myometrium, isoproterenol (10-8 M) inhibited spontaneous contractions without causing hyperpolarization. Isoproterenol (10-6 M) relaxed the depolarized muscle without affecting the membrane potential. The presence of 80 mM Na+ did not affect the degree of high-K+ depolarization. It was also without any influence on the effects of isoproterenol on the depolarized uterus. The results are consistent with the concept that hyperpolarization is not a prerequisite for β-adrenoceptor induced relaxation of uterine smooth muscle. © 1979.