Effects of oxamniquine on chick isolated esophagus

The effects of oxamniquine, a potent schistosomicide, on chick isolated esophagus have been examined. Oxamniquine (2.5 X 10(-8)-5 X 10(-5) M) caused rhythmic and tonic contractions of the chick isolated esophagus. The concentration of oxamniquine required to produce 50% of the maximal contractile response (EC50) was 4.2 X 10(-5) M. Pre-incubation of the muscle preparation with procaine (40-120, microM), scopolamine (0.40 microM) or indomethacin (10 microM) attenuated oxamniquine-induced myogenic contractions of the muscle preparation. It is suggested that inhibition of oxamniquine-induced contractions by indomethacin, scopolamine or procaine probably indicates that oxamniquine-induced contractions of the muscle preparation is due to the release of a prostaglandin-like substance and/or a yet unknown contractile compound from the muscle.