title: Effect of atrial natriuretic factor on transmural myocardial blood flow distribution in the dog.
abstract: These studies were designed to define the effect of atrial natriuretic peptide (ANP) on coronary flow. ANP was infused as a bolus directly into the left circumflex coronary artery in doses ranging from 0.05 to 5 micrograms in nine open-chest, anesthetized dogs. Coronary flow was measured with an electromagnetic flowmeter. Regional transmural myocardial blood flow and distribution were measured with 11.3 +/- 0.25 micron radionuclide-labeled microspheres. No significant change was noted in systemic hemodynamics (heart rate, arterial pressure, left atrial pressure, or cardiac output) during the course of the studies. ANP produced a transient vasodilatation of coronary resistance vessels and increased flow by 41% after both the 2.5 and 5 micrograms doses. The vasodilatation occurred uniformly throughout the ventricular wall so that the endocardial/epicardial flow ratio remained constant. There was no evidence of coronary vasoconstriction. The peak vasodilatation response occurred 28 +/- 7 sec after the beginning of the infusion of ANP and lasted approximately 3 min. These data support the hypothesis that ANP administration is associated with a vasodilator response in the coronary resistance vessels that may be modulated through either the release of another vasodilator substance or another mechanism.
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000008:administration & dosage / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003326:Coronary Circulation / Q000187:drug effects*; D003331:Coronary Vessels / Q000187:drug effects; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D008863:Microspheres
chemical_list: D009320:Atrial Natriuretic Factor