Responses of the monkey oviduct to transmural electrical stimulation and to drugs

In monkeys, as in man, the time required for ovum transport through the oviduct is about 3 days(Eddy, Garcia, Kraemer & Pauerstein, 1976). This period appears essential for normal fertility because eggs passing too quickly or too slowly through the oviduct fail to implant (Bennett, 1974). Although transport through the ampulla may be mediated by cilia (Blandau & Verdugo, 1976), the isthmus is comparatively muscular and well innervated and may delay ovum transport by a sphincter-like action. Prostaglandins and catecholamines are known to alter the muscular activity of human and rabbit oviducts and it is possible that changes in the levels of these drugs, or in the sensitivity of the tissues to them, may control egg transport (Hodgson & Eddy, 1975; Spilman & Harper, 1975). In the present study the contractile responses of the monkey oviduct to various drugs and to trans-mural electrical stimulation have been examined in the hope of increasing understanding of the regulation of ovum transport in this species. Tissues were obtained from mature female crabeating macaques (Macaca fascicularis). Uteri with their attached oviducts were removed under halothane anaesthesia and were placed in cold Krebs solution. Each oviduct was then separated from the uterus and the attached connective tissue and ligaments dissected away. One4-mmand two2-mm lengths oftube were then obtained from both the isthmic and the ampullary regions. The shorter lengths were connected together with thread in the form of rings for recording of circular muscle activity; the longer sections were suspended longi¬ tudinally. Both types of preparation were suspended in Krebs solution at 37°C under a tension o