Large Coronary Artery Regulation by α- and β-Adrenergic Receptors in Conscious Calves

摘要: Regulation of coronary arteries by α- and β-adrenergic receptor subtype mechanisms was examined in chronically-instrumented, conscious calves. The physiological data on receptors were correlated with ligand binding studies from sarcolemmal membranes calf large arteries. In the animal, selective α1- + α2- β1 - β2-adrenergic agonists presence absence α2-, β1- blockades. Both α1-adrenergic agonist, phenylephrine, α2-adrenergic B-HT 920, induced similar vasoconstriction calf, whereas β1-adrenergic prenalterol, pirbuterol, vasodilation. These effects abolished their respective adrenergic blocker, but not significantly affected corresponding blocker for other subtype. Ligand demonstrated both subtypes receptors, a predominance subtypes. Thus, contain subtypes, are capable eliciting significant constriction either α-adrenergic dilation