Antiallergic activity of nylidrin hydrochloride (RHC 3432-A). I. Effect on release of histamine in vitro from rat peritoneal mast cells, guinea pig lung slices and human basophils

Nylidrin (RHC 3432-A) has been investigated for its antiallergic activity in three in vitro models. Nylidrin was an effective inhibitor of IgE-mediated release of histamine from passively sensitized rat peritoneal mast cells and human basophils, and of IgG1-mediated release of histamine from passively sensitized guinea pig lung slices. The inhibition of the release of histamine by nylidrin in all three models was not antagonized by propranolol, indicating that nylidrin does not inhibit histamine release via stimulation of beta-adrenergic receptors. Isoproterenol and epinephrine were effective as inhibitors of the release of histamine only from guinea pig lung while salbutamol and terbutaline had no effect on immunologic release of histamine in all three models. Detailed comparative studies with disodium cromoglycate (DSCG) indicated that the mechanism of action of nylidrin in the rat mast cell model is different from that of DSCG.