The role of coronary flow and pressure as determinants of myocardial oxygen consumption in the presence or absence of vasomotor tone.
When coronary flow was kept constant and coronary pressure increased by angiotensin or decreased by dipyridamole, myocardial oxygen consumption (MVO2) remained unchanged. When vasomotor tone was abolished by dipyridamole or was intact, changing coronary flow resulted in a change in MVO2 in the same direction as flow; this change in MVO2 was in part the result of a significant alteration in coronary oxygen extraction. These results suggest that coronary flow, but not coronary pressure is an important determinant of MVO2 both in the presence or absence of vasomotor tone.
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001808:Blood Vessels / Q000187:drug effects / Q000502:physiology*; D003326:Coronary Circulation / Q000187:drug effects; D004176:Dipyridamole / Q000494:pharmacology; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D009129:Muscle Tonus / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects
D000804:Angiotensin II; D004176:Dipyridamole