Abstract:

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-α), 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-α enhanced its contractions. In the isthmus, PGE1, PGE2, and PGF2-α 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. This study examines the possible role of endogenous prostaglandins (indomethacin; PGF2a; PGE1; PGE2; and prostacyclin or PGI2) on the spontaneous motility of the human ampullar and isthmus deprived of the mesosalpinx. Fallopian tubes were obtained from 12 patients who had hysterectomy and salpingo-oophorectomy. The segments of the tubes were prepared for contractile recordings as previously described and divided into 2 groups: 1) ampullar and isthmic segments were followed by spontaneous variations in motility during 30 minutes; and 2) cumulative close-response curves for PGI2 were constructed for ampullar and isthmic segments 30 minutes after the end of equilibrium. Contractile functions were evaluated in terms of amplitude of isometric developed tension (IDT) and frequency of contraction, and when pertinent, changes in resting basal tone. Student's t-test was used for statistical analysis, and differences between means were considered significantly at P=0.05 or less. Indomethacin significantly enhance the IDT of the isthmic but not the ampullar region. However, a single and identical concentration of 10-6M of PGE1 and PGI2 depressed the ampullar while PGE2 and PGF2a enhanced its contractions. In the isthmus, PGE1, PGE2 and PGF2a augmented while PGI2 diminished the IDI. Both ampullar and isthmic regions exhibited a dose-dependent depression of IDI and contractile frequency. In the isthmus, PGI2 produced a biphasic action on resting basal tone while in the ampulla, only a progressive dose-dependent decline was seen. Prostacyclin may be synthesized by the isthmic region of the human fallopian tubes, but whether it occurs in vivo or what its physiological significance is remains to be seen.