INVOLVEMENT OF SRS-A IN THE SCHULTZ-DALE RESPONSE OF THE GUINEA-PIG SMALL-INTESTINE

The anaphylactic reaction of the guinea‐pig ileum, the so called Schultz‐Dale reaction, shows a biphasic response: a short rapid contraction followed by a partial relaxation and a slow contractile response. Dose‐response curves with ovalbumin as an antigen were obtained for the quick and slow contraction of this anaphylactic reaction. Mepyramine (1 μg/ml) blocked the rapid first contraction, but failed to abolish the slow one in about 50% of the animals studied. The SRS‐A antagonist, FPL 55712, significantly depressed the slow sustained contraction during the Schultz‐Dale reaction. Disodiumcromoglycate was without effect on both phases when it was added 5 min before addition of the antigen. However, when added simultaneously with the antigen it produced a 30% suppression of the slow phase in the highest concentration used. 1979 British Pharmacological Society