Role of oxygen extraction from coronary blood in the regulation of oxygen transport to the myocardium
Novikova, E.B.; Tskitishvili, O.V.
Biulleten' Eksperimental'noi Biologii i Meditsiny 95(1): 3-5
1983
ISSN/ISBN: 0365-9615 PMID: 6830953 Document Number: 205705
Experiments on anesthetized dogs were made to examine oxygen extraction from coronary blood during increase and decrease in cardiac rhythm frequency under varying conditions of vasomotor regulation. With an initially high tone of the coronary vessels both increase and reduction of myocardial oxygen supply occurred at the expense of vasomotor reactions. Under these conditions the coronary blood flow velocity and systolic rhythm correlated well. At the same time the oxygen level in coronary blood did not experience noticeable changes. As the initial tone of the coronary vessels dropped, vasomotor reactions were attenuated and oxygen extraction from coronary blood underwent alterations which had occurred prior to depletion of the coronary expanding reserves. The data obtained suggest that reduction of the initial tone of the coronary vessels proceeds non-uniformly, leading to a decrease in vascular sensitivity to the tissue oxygen level.