Effects of ovulation on the conduction and contraction velocities in rabbit oviduct: contrasts between longitudinal and circular muscle.

The contraction and electrical conduction velocity of the longitudinal and circular muscle of the oviduct from rabbits in estrus, 24 or 72 h following administration of human chorionic gonadotropin (hCG) or 14 days following castration have been compared. Two populations of conduction and contraction velocities were identified, with the faster velocity being associated with the longitudinal muscle. There was a large overlap between longitudinal and circular contraction, suggesting complex relationships between longitudinal and circular muscle. From the results it appears that during ovum transport the circular velocities increased, with the slowest rates at estrus. The values obtained 72 h following hCG injection most closely resembled those in the castrate group of animals. In the longitudinal orientation, however, the velocities were greater 24 h following hCG injection than at estrus or 72 h following hCG injection, suggesting a complex relationship between both longitudinal and circular muscle of the oviduct following ovulation.