[An animal model for screening of antiallergic and antipruritic drugs].

4-Aminopyridine(4-AP) 1 mg.kg-1 sc at the scruff induced a licking response in mice. Antiallergic and antipruritic drugs, such as diphenhydramine HCl(20 mg.kg-1 ip), doxepin(12.5 mg.kg-1 ig), prednisone(10 mg.kg-1 ig), dexamethasone(10 mg.kg-1 ip), fluocinolone (applied to the surface of skin), Pi Yan Ping(applied to the surface of skin), disodium cromoglicate(400 mg.kg-1 ip), ketotifen(1 mg.kg-1 ip), etc. markedly inhibited the licking response elicited by 4-AP. The calcium antagonist nifedipine(500 mg.kg-1 lg) and the potassium channel opener minoxidil(400 mg.kg-1 ig) produced the same inhibitory effect. H2-receptor antagonist cimetidine(200 mg.kg-1 ip) and ranitidine(150 mg.kg-1 ip) showed no effect. Morphine HCl(10 mg.kg-1 ip) and diazepam(0.02 mg.kg-1 ip) exhibited antagonistic effect on the licking response induced by 4-AP, but phenobarbital(25 mg.kg-1 ip), pentobarbital(15 mg.kg-1 ip) and aspirin(300 mg.kg-1 ig) did not. These results indicate that many antiallergic or antipruritic drugs inhibited the licking response induced by 4-AP. The method of licking response elicited by 4-AP has the merit of simplicity and convenience and may be used for screening antiallergic and antipruritic drugs.