AJP - Heart and Circulatory Physiology, Vol 248, Issue 4 516-H522, Copyright © 1985 by American Physiological Society
Effects of vasopressin on the coronary circulation: reserve and regulation during ischemia
M. A. Khayyal, C. Eng, D. Franzen, J. A. Breall and E. S. Kirk
In 18 dogs, intracoronary infusion of vasopressin produced a 40% reduction
in coronary flow without significantly affecting systemic hemodynamics. The
blood flow reduction occurred in a uniform transmural pattern without
evidence of a gradient. The reduction in coronary flow resulted in a
decrease in regional contractility as determined by isometric strain gauge
arches. The decrease in regional contractility was transiently reversed by
bolus injection of adenosine into the perfusion line. This suggests that
the reduction of blood flow due to vasopressin was causing ischemia.
Evidence for ischemia was also supported by measurements of local vein and
tissue lactate production. Despite the apparently ischemic conditions, the
vascular bed demonstrated evidence for significant reserve and regulation.
Pressure-flow relationships performed under control and during vasopressin
infusion demonstrated that the coronary vasculature retained its ability to
regulate or defend a given level of coronary flow over a range of coronary
perfusion pressures. Vasopressin produced a mild decrease in the peak
hyperemic flow after a 15-s coronary occlusion and shortened the duration
of reactive hyperemia. These overall findings are compatible with a
predominant vasoconstrictor effect on the distal coronary vasculature. A
role for a myogenic factor in the control of the coronary circulation is
suggested, which is amplified by vasopressin.
