Direct coronary vasodilator action of adrenomedullin is mediated by nitric oxide

Abstract

1. Increased circulating levels of adrenomedullin (ADM) cause peripheral vasodilatation and hypotension, accompanied by cardiac actions including tachycardia and increases in cardiac contractility, cardiac output, coronary conductance (CC) and coronary blood flow (CBF). It is unclear to what extent these cardiac effects are direct actions of ADM or secondary to the hypotension and altered cardiac loading. 2. The direct cardiac actions of ADM were examined in conscious sheep previously implanted with aortic and coronary flow probes, and an indwelling left coronary artery cannula. Responses to infusion of ADM (0.5 μg kg -1 h -1 for 1 h) into the left coronary artery or jugular vein were compar..