The effects of antiinflammatory steroids on the response of the guinea-pig isolated ileum to acetylcholine, histamine, nicotine, 5-hydroxytryptamine and electrical stimulation.

High concentrations of antiinflammatory steroids (2.5–40 μg/ml) reversibly inhibited the electrically induced contractions of the guinea-pig isolated ileum. At 40 μg/ml they also reversibly inhibited contractions clicited by acetylcholine, histamine, nicotine and 5-hydroxytryptamine. PGE1 (2.5 ng/ml), PGE2 (2.5 ng/ml) and PGF2α (25 ng/ml) antagonized these effects.