The inhibitory effect of histamine on the motility of rat uterus in vivo.
The experiments concerned the effects of histamine and its analogs 4-methylhistamine and 2-pyridyl-ethylamine on the spontaneous activity of the estrogenized rat uterus in vivo. These agonists given intravenously inhibited uterine activity. Histamine and 4-methylhistamine, but not 2-pyridyl ethylamine, produced this effect in a dose-dependent manner. The ability of histamine to reduce uterine activity was lowered by pretreatment with reserpine, adrenalectomy or 6-hydroxydopamine. The effect of 4-methylhistamine also was reduced by reserpine or adrenalectomy. The inhibitory effect of 2-(2-pyridyl) ethylamine was completely abolished by reserpine or adrenalectomy. Cimetidine attenuated the residual inhibitory effect of histamine in reserpinized rats. These results suggest that the uterine inhibitory action of histamine and 4-methylhistamine is mediated through catecholamine release and direct stimulation of the H2-receptors. The effect of 2-(2-pyridyl) ethylamine is only mediated by release catecholamine.
D000315:Adrenalectomy; D000818:Animals; D002395:Catecholamines / Q000378:metabolism; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006892:Hydroxydopamines / Q000008:administration & dosage; D008761:Methylhistamines / Q000494:pharmacology; D016627:Oxidopamine; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011969:Receptors, Histamine H1 / Q000502:physiology; D011970:Receptors, Histamine H2 / Q000502:physiology; D012110:Reserpine / Q000008:administration & dosage; D014590:Uterine Contraction / Q000187:drug effects*; D014599:Uterus / Q000502:physiology*
D002395:Catecholamines; D004967:Estrogens; D006892:Hydroxydopamines; D008761:Methylhistamines; D011725:Pyridines; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; C025566:4-methylhistamine; D006632:Histamine; D012110:Reserpine; D016627:Oxidopamine; C006183:2-(2-aminoethyl)pyridine