Purpose: Our purpose was to elucidate the roles of the ampullar and isthmic portions of the oviduct and the effects of drugs on oviductal contractility.
Methods: Prostaglandin F2 alpha (PGF2 alpha; Ono Pharmaceuticals, Osaka) and oxytocin (Atonin-O; Teikoku Hormone Manufacturing Co. Ltd., Tokyo) were used to stimulate oviductal contractility, and ritodrine hydrochloride (Utemerin; Solvay-Duphar Corp., Denmark) to inhibit the contractility.
Results: Both PGF2 alpha and Atonin-O were involved in ovum capture by the ampullar oviduct by stimulating contractility, thus altering the intraductal pressures. Utemerin is effective in inhibiting the enhanced contractility induced by PGF2 alpha and Atonin-O.
Conclusions: Variations in pressure of the ampullar portion of the oviduct seem necessary for the capture of ova expelled from the ovary. Once in the isthmic portion of the oviduct, transport appears to be under the influence of ciliary activity rather than variations in contractility.