1982 Volume 31 Issue 9 Pages 970-976
We studied the effect of H_1 and H_2 histamine antagonists on bronchoconstriction induced by histamine and methacholine in monkeys. The bronchoconstriction was induced by aerosol challenge with histamine and methacholine. The histamine blockers were intravenously injected. Pretreatment with diphenhydramine(H_1 histamine antagonist) significantly suppressed increase in total respiratory resistance(Rrs.) due to histamine aerosol challenge, and it also suppressed that due to methacholine to a slight degree. Pretreatment with H_2 histamine antagonist, metiamide 73 mg and cimetidine 76 mg, had no effect on bronchoconstriction due to histamine or methacholine. The injection of H_1 blocker also reduced histamine-induced bronchoconstriction by 61.2% in total respiratory resistance(Rrs.), and the methacholine-induced by 43.5%. Howere, the injection of H_2 blocker did not produce uniformal change in the elevated Rrs. induced by histamine and methacholine.
