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 sphincterlike 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 transmural 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 of 490 or 980 dyn. The Krebs solution consisted of (ihm) : Na+, 139 ; K+, 5-4 ; Ca2+, 2-5 ; Mg2+, 1 -2 ; Cl", 129; HCO3-, 22; H2PO,r, 1-2; D-glucose, 11-1, and was bubbled with 95% 02 + 5% C02. During transmural electrical stimulation, tissues were continuously superfused with Krebs solution at 1-2 ml/min. The medium had a pH of 7-40 ± 002. Tension was recorded by using Grass FT03C trans¬ ducers and displayed on Dynograph or Grass pen recorders. Compounds were added to the organ baths, 5 or 10 ml volume, as small (10-50 pi) amounts of stock solutions. The baths were washed out with fresh Krebs solution when the tissues had produced