Animal and human ocular surface response to a topical nonimmune mast-cell degranulating agent (compound 48/80)

Topical application of the nonimmune selective mast-cell degranulating agent, compound 48/80, produced the signs and symptoms of ocular allergy (itching, injection, chemosis, and mucous discharge) in eight guinea pigs, eight rabbits, and nine humans. The histamine H1 receptor antagonist, antazoline phosphate, blocked itching but not vasodilation in five humans pretreated with compound 48-80. This suggests that histamine was one of the mediators released by compound 48-80-induced degranulation. Compound 48-80 may be helpful in evaluating the effects of therapeutic agents capable of modifying mast-cell degranulation and in the study of mediators involved in external ocular inflammation.