The effect of prostaglandins on the electromyogram and motility of the monkey uterus and oviduct in late pregnancy and postpartum.

The electromyogram of the monkey (Macaca fuscata fuscata and Macaca mulatta) uterus in labor presents spike bursts which accompany the rising intrauterine pressure. Asynchronous localized electrical activity develops into synchronous activity during the course of labor. The early postpartum uterus shows an irregular pattern or continuous small bursts of spikes. During labor it responds markedly to prostaglandins (PGs); this declines in postpartum. Direct intrauterine injection of PGF2a is effective in the early postpartum. Intravaginal application of PGE2 (5 mg/kg) in late pregnancy induces regular, frequent bursts of spikes and successful delivery. Electrical activity of the oviduct was not affected by PGs except in early postpartum.