Nature of histaminergic receptors in goat uterus

Histamine and 2-pyridylethylamine (2-PEA) caused contraction while dimaprit produced relaxation of isolated goat (Capra hircus) uterine strips. Wherea s mepyramine blocked the histamine and 2-PEA-induced contractions, chlorphe niramine reversed the contraction to relaxation. Metiamide potentiated the histamine-induced contraction and blocked the relaxant effect of dimaprit. Caffeine, papaverine and propranolol did not alter dimaprit-induced relaxat ion, however, unlike caffeine and propranolol, papaverine inhibited the con tractile response to histamine. These observations suggest that goat uterus possesses both H-1 excitatory and H-2 inhibitory histaminergic receptors.