Characterization of various antiallergic agents using a new method for inducing systemic anaphylaxis in the rat

Five different types of antiallergic agents were studied using a newly developed method for inducing IgE-mediated bronchial and cardiovascular anaphylaxis in the rat. With the exception of the histamine H1 antagonist mepyramine (no activity at all), each antiallergic tested showed a different and characteristic profile of antiallergic activity. Prednisolone and the SRS-A antagonist FPL 55712 protected the rats completely against mortality, whereas cromoglycate and ketotifen offered only partial protection. The cardiovascular events were favorably influenced by FPL 55712 and cromoglycate, but ketotifen was completely ineffective in this respect. However, ketotifen showed the highest activity in suppressing the antigen-induced bronchoconstriction, followed by cromoglycate and prednisolone, whereas FPL 55712 was practically inactive. It can be concluded that the antiallergic activity of various types of antiallergics can be characterized and differentiated by means of this highly reproducible method.