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 indometha-cm. 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 F20 (PGF20) 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 gener-ating PGs from both endogenous and exogenous substrate. The data also suggest that the forma-tion of PGF20 is a prerequisite for maintenance of normal tubal contractions