AJP - Heart and Circulatory Physiology, Vol 243, Issue 3 410-H415, Copyright © 1982 by American Physiological Society
Regional coronary vasoconstriction in response to stimulation of stellate ganglia
L. E. Rinkema, J. X. Thomas Jr and W. C. Randall
Recent experiments have demonstrated that direct and reflex sympathetic
stimulation elicit coronary vasoconstriction when the inotropic and
chronotropic effects are blocked with beta-adrenergic blocking agents. This
vasoconstriction can be blocked with alpha-adrenergic blocking agents.
Regional variations in the flow reduction produced by right (RSS) vs. left
(LSS) stellate stimulation were delineated in this study. Open-chest
pentobarbital-anesthetized dogs were given propranolol (1 mg/kg iv). Hearts
were neurally decentralized and paced just above the spontaneous heart
rate. Radiolabeled microspheres (15 +/- 2 micrometers) were injected into
the left atrium before and during RSS (n = 11) or LSS (n = 11). RSS
produced relatively little vasoconstriction confined to anterior left
ventricle. In contrast, LSS produced significant vasoconstriction in all
areas of the right and left ventricles. In the endocardial half of the left
ventricle the flow decrease was uniformly distributed among the regions
studied. In the epicardial half of the flow decrease was more pronounced in
posterior than in anterior regions. No significant change occurred in the
endo-epi ratios with RSS, but with LSS there was a significant change in
three areas. The changes were related to regional variations in the degree
of epicardial constriction. Thus RSS and LSS have differential effects
(quantitatively) on regional coronary blood flow.
