Studies on heparin in allergic reactions 1. Action of heparin on immediate hypersensitivity

The action of heparin on allergic reactions was examined in skin and bronchial reactions to chemical mediators, in the rat PCA reaction and antigen-induced degranulation of rat peritoneal mast cells. Heparin inhibited the histamine-induced skin reaction in rats. Bronchoconstriction caused by histamine and acetylcholine was also inhibited by pre-treatment with heparin. The skin reaction due to reaginic antibody (PCA), but not that due to precipitated antibody, in rats was inhibited by heparin administration. Heparin moderately inhibited the degranulation of rat peritoneal mast cells elicited by reaginic antibody, but the inhibitory action was not as strong as that of prednisolone or disodiumcromoglycate.