[The importance of histaminergic H1 and H2 receptors for the contractile effect of histamine on human umbilical veins].

Influence of histamine and histaminergic H1 blockers (antazoline, promethazine) and H2 blockers (cimetidine, ranitidine) on isometric contraction of helically cut strips of human umbilical vein was examined. Histamine produced dose-related contraction of the vein strip, while histaminergic H1 and H2 blockers did not changed the tonus of the vein. The contractile activity of histamine was not influenced by cimetidine or ranitidine, while antazoline and promethazine antagonized mentioned activity of histamine completely. We suppose that histamine exerts contractile effect of human umbilical vein by acting on H1 receptors while H2 receptors are not involved in the mentioned activity of histamine.