EFFECT OF TYB-2285 ON PASSIVE CUTANEOUS ANAPHYLAXIS IN RATS

1. TYB-2285 (1-30 mg/kg PO) inhibited ovalbumin (OA)- and dinitropheny l-ascaris (DNPAs)-induced passive cutaneous anaphylaxis (PCA) in a dos e dependent manner. 2. The ED(50) of TYB-2285 and ketotifen fumarate o n OA induced PCA were 0.5 and 3.9 mg/kg, respectively. The ED(50) Of T YP-2285 and amlexanox on DNP-As-induced PCA were 3,5 and 0.9mg/ kg, re spectively. 3. TYB-2285 (3-30 mg/kg PO) inhibited histamine consumptio n at the PCA site. 4. Unlike cyproheptadine or amlexanox, TYB 2285 (30 mg/kg PO) did not inhibit histamine-, se rotonin-, ascites-, 48/80-, or A23187-induced capillary permeability. It inhibited dextran-induced capillary permeability slightly. 5. These results demonstrate that TY B-2285 inhibits PCA by inhibiting histamine release, although it does not inhibit capillary permeabilty. Copyright (C) 1997 Elsevier Science Inc.