A pharmacological study of SRS-A on the bovine cutaneous vasculature.

Bovine slow-reacting substance of anaphylaxis (SRS-A) is capable of producing dose-dependent vascular permeability changes in the skin of calves. The wheals are well-defined indurations, similar to wheals induced by histamine but different from those induced by prostaglandin (PG) E2. Three proposed SRS-A receptor blockers (i.e., FPL 55712, PR-D-92-EA, and sodium meclofenamate) were studied with respect to their antagonism of wheals induced by SRS-A, histamine, and PGE2. PR-D-92-EA and FPL 55712 antagonized SRS-A, and also histamine and PGE2 at high concentrations. Meclofenamate was ineffective against SRS-A but antagonized histamine and PGE2 at higher concentrations. The significance of these results, especially with respect to passive cutaneous anaphylaxis, is discussed.