Segmental alpha-receptor-mediated vasoconstriction in the canine coronary circulation.
- 1 December 1978
- journal article
- research article
- Published by Wolters Kluwer Health in Circulation Research
- Vol. 43 (6), 908-917
- https://doi.org/10.1161/01.res.43.6.908
Abstract
Recent studies from this laboratory have indicated that sympathetic alpha-receptor-mediated coronary vasoconstriction can compete with local metabolic vasodilation to reduce the oxygen supply to the myocardium. In vitro studies from other laboratories on isolated coronary vessel strips suggest that large epicardial vessels are the dominant site of adrenergic alpha-receptor activity. In this study we used anesthetized, open-chest dogs to test the hypothesis that alpha-receptor-mediated vasoconstriction occurs predominantly in epicardial vessels, which are partially removed from the metabolic milieu in the myocardium. Adrenergic beta-receptor blockade was achieved by propranolol (3 mg/kg, iv). The circumflex coronary artery was pump-perfused at constant pressure to minimize passive changes in large vessel resistance. Pressure was measured at the tip of the perfusion cannula sealed in the circumflex artery, and in an apical branch of the circumflex artery. Large vessel resistance was calculated as the pressure gradient along the vessel segment divided by the coronary flow. Intracoronary injections of nitroglycerin were used as an independent measure of the vasomotor responsiveness of the large vessel segment. Adrenergic alpha-receptor activation was produced by intracoronary bolus injections of norepinephrine and by electrical stimulation of the left stellate ganglion. Alpha-receptor stimulation caused an increase in total coronary vascular resistance; however, the relative increase in the resistance of the large vessel was only about 60% of that seen for the entire coronary bed. These data suggest that, contrary to the proposed hypothesis, adrenergic alpha-receptor-mediated vasoconstriction in the large coronary vessels is not proportionally greater than that observed in the total coronary vascular bed.This publication has 28 references indexed in Scilit:
- Effects of Coronary Vasodilators on Large and Small Coronary Arteries of DogsJapanese Heart Journal, 1977
- Regional Myocardial Blood Flow in Awake DogsJCI Insight, 1974
- Effect of stellate ganglion stimulation on myocardial blood flow, oxygen consumption, and cardiac efficiency during beta-adrenoceptor blockadeCardiovascular Research, 1973
- Control of myocardial oxygen consumptionThe American Journal of Cardiology, 1971
- Responses of coronary vessels to adrenergic stimuliJCI Insight, 1971
- Effect of Prolonged Chloralose Anesthesia on Acid-Base Balance and Cardiovascular Functions in DogsActa Physiologica Scandinavica, 1971
- The effect of vasoactive drugs on local coronary flowCanadian Journal of Physiology and Pharmacology, 1969
- Effects of Right and Left Cardiosympathetic Nerve Stimulation on Blood Flow in the Major Coronary Arteries of the Anaesthetized DogCardiovascular Research, 1969
- Sympathetic Coronary Vasoconstriction after Adrenergic Beta BlockadeThe Tohoku Journal of Experimental Medicine, 1967
- Catheter Replacement of the Needle in Percutaneous Arteriography: A new techniqueActa Radiologica, 1953