Responses of isolated human epigastric arteries to histamine.

Responses to histamine have been studied on ring preparations of epigastric artery obtained from normal and from pregnancy-induced hypertensive (PIH) women to characterize the mode of action of histamine in this vascular preparation. In non-contracted arterial rings, histamine elicited concentration-dependent H1 receptor-mediated contractions, competitively antagonised by mepyramine and cicletanine with pA2 values of 9.1 and 7.

In vitro vascular effects of cicletanine in pregnancy-induced hypertension.

1. The vascular effects of cicletanine have been studied in vitro on ring preparations of inferior epigastric arteries from normotensive human females and human females with pregnancy-induced hypertension (preeclampsia). 2.

Effects of cicletanine on histamine-induced contractions of isolated rabbit mesenteric arteries.

The antagonism by cicletanine of contractile responses to histamine has been examined in vitro on ring preparations of rabbit mesenteric arteries. Cicletanine (10(-8)-10(-6) M) caused a parallel rightward shift of histamine concentration response curve, with a pA2 value of 7.48 (slope = 0.

Histamine H1-receptors mediate phosphoinositide and calcium response in cultured smooth muscle cells--interaction with cicletanine (CIC).

Smooth muscle cells were cultured from guinea-pig aorta and labelled with 45Ca++ and 32Pi to investigate the possible effect of cicletanine, a new antihypertensive drug, on the release of intracellular Ca++ and the metabolism of phosphoinositide induced by histamine. In 45Ca++ labelled cells, histamine increased in a dose-dependent manner the 45Ca++ efflux in the first two minutes. Stimulation of 45Ca++ release was observed with H1-agonist [2-pyridylethylamine dihydrochloride (2-PEA)] but not with H2-agonist (dimaprit).

The role of histamine in the cardiovascular system.

This article reviews briefly the role of histamine through its H1 and H2 receptors on the cardiovascular system and its action on calcium and catecholamines. The analogy between the adrenergic and the histaminergic systems is well demonstrated and there is evidence that histamine participates in myocardial damage and arrythmias, but the question of its exact role in the early stages of cardiovascular diseases, such as myocardial ischaemia and atherosclerosis, requires further study.