Influence of Cyclooxygenase Inhibitors and Arachidonic Acid on Contractile Activity of the Human Fallopian Tube

Small muscle strips were dissected from the circular and longitudinal muscle layers of the human oviduct. The preparations showed rhythmic spontaneous activity when perfused by Krebs-Ringer buffer. Excitatory effects of the prostaglandin (PG) precursor arachidonic acid were totally blocked by the cyclooxygenase inhibitors 5,8,11,14-eicosatetraynoic acid (ETYA) and indomethacin. The latter drugs also caused a reversible inhibition of spontaneous activity in both muscle layers. After total inhibition produced by ETYA, the initial activity was restored by adding low concentrations of prostaglandin F2 alpha (PGF2 alpha) to the medium. PGE2 was able to reestablish the activity only in the longitudinal layer. It is concluded that isolated smooth muscle of the human oviduct has the capacity of generating PGs from both endogenous and exogenous substrate. The data also suggest that the formation of PGF2 alpha is a prerequisite for maintenance of normal tubal contractions.