Intraluminal pressure changes in the oviduct, uterus, and cervix of the mated rabbit.

Simultaneous recordings of intraluminal pressure in the ipsilateral oviduct, uterus, and cervix were made to estimate pre- and postcoital changes in their motilities. In the estrous state, there were daily variations with some cyclical fluctuations in the contractile activity in each organ. After normal mating, oviductal motility amplitude increased to a peak on Day 1.5 and then declined gradually during the period of egg transport through the oviductal isthmus, whereas in superovulated does such an initial peak in the motility was very small or not detected. At the time when eggs were expected to enter the uterus, the uterine and cervical motility decreased to the lowest level and was characterized by intermittent contractions of small amplitude. The oviductal motility was also depressed, but never completely suppressed, throughout pregnancy. In animals which did not become pregnant, motilities in these three organs began to increase on Days 16-18, and subsequent motility patterns were similar to those of the precoital state. In pregnant does, depressed activity, first noted during week 1 of pregnancy, was maintained up to delivery. Intraluminal pressure changes in the reproductive tract are discussed in relation to the rate of egg transport.