The microvasculature plays a significant role in the regulation of blood pressure and regional blood supply. Cardiotonic steroids like the adrenal cortical hormone (ouabain) have been proposed to play a role in some forms of hypertension. The purpose of this study was to determine the effect of different agonists on arteriolar diameter in the presence and absence of ouabain.
In Vitro studies on isolated intact rat mesenteric arterioles were performed by administering different concentrations of the vasoconstrictor norepinephrine (NE) and the vasorelaxant acetylcholine (Ach) in the presence and absence of ouabain. NE induced constriction was not significantly enhanced in the presence of ouabain. Ach completely reversed NE-induced constriction without ouabain, which was significantly impaired in ouabain presence (p+Channel blockade almost completely abolished Ach-induced relaxation in presence and absence of ouabain.