[Contractile properties of smooth muscle cells of the horns, cervix and broad ligament of the pig uterus].

Physiological properties of the pig uterus smooth muscle of different regions revealed similarities as well as differences depending on the phase of reproduction cycle. Smooth muscle of the pregnant pig horn contains a large number of beta-adrenoreceptors important for inhibition of the uterine contractions. At the late pregnancy their number decreases while the smooth muscle of the uterine cervix loses its sensitivity to acetylcholine, histamine and oxytocin which is important for induction of parturition.