Histamine H1- and H2-receptors in the mesenteric vascular bed of the pig.

In order to study whether both histamine H1- and H2-receptors are present in the pig mesenteric vascular bed, natural histamine, 2-(2-pyridyl) ethylamine and 4-methylhistamine, as well as mepyramine and metiamide, were infused directly into the superior mesenteric artery. The results indicate that histamine H1- and H2-receptors, both inducing vasodilation, are present in the mesenteric circulation of the pig. Jejunal motility proved to be influenced by H1-receptor stimulation only.