Spontaneous motility of isolated mesosalpinx-free isthmic and ampullar segments from human oviducts, and the influences of indomethacin and prostacyclin (PGI2).

The spontaneous contractile activity of isolated mesosalpinx-deprived isthmic and ampullar segments from estrogen dominated human oviducts and the influences of indomethacin, prostaglandin F2-alpha, (PGF2-alpha), E1 (PGE1), E2 (PGE2) and prostacyclin (PGI2) on their motility, were explored. Indomethacin enhanced significantly the Isometric Developed Tension (I.D.T.) of the isthmic but not the ampullar region. On the other hand, a single and identical concentration (10(-6) M) of PGE1 and PGI2 depressed the ampulla whereas PGE2 and PGF2-alpha enhanced its contractions. In the isthmus, PGE1, PGE2, and PGF2-alpha augmented whereas PGI2 diminished the I.D.T. Dose-response curves of PGI2 demonstrated a dose-dependent depression of I.D.T. and contractile frequency of both ampullar and isthmic regions. Furthermore, in the isthmus PGI2 resulted in a biphasic action on resting basal tone (depressing at low and augmenting at high concentrations), whereas in the ampulla only a progressive dose-dependent decline, was observed. The results suggest that a prostaglandin with inhibitory capacity, presumably PGI2, may be synthesized by the human isthmus and play some role in the reduced spontaneous activity observed under estrogenic dominance.