Effects of pharmacological inhibition of histamine synthesis upon immunological reactions in guinea-pigs

Abstract

Administration of a specific histidine decarboxylase inhibitor, 4-bromo-3-hydroxybenzyloxyamine (brocresine) failed to affect PCA or delayed hypersensitivity reactions in guinea-pigs. Skin histamine levels measured following PCA reactions, when the skin was refractory to a second stimulus showed no significant changes in both treated and untreated animals. Triprolidine, an antihistamine, also failed to significantly alter PCA reactivity. These findings may be interpreted to mean that the operative pool of histamine is very small, its production unaffected by brocresine and its action protected from the effects of antihistamines. Alternatively, it seems more likely that histamine plays little role in the PCA reactions of guinea-pigs.