Circulation Research, Vol 48, 214-223, Copyright © 1981 by American Heart Association

ARTICLES

Mechanisms mediating the coronary vascular response to behavioral stress in the dog

GE Billman and DC Randall

Left circumflex coronary blood flow (CBF) was measured in eight mongrel dogs with 8 MHz continuous wave Doppler flow transducers during classical aversive conditioning. The cardiovascular condition response consisted of significant (P less than 0.01) increases in: (1) mean aortic pressure (16.1%), (2) d(left ventricular pressure)/dt (64.2%), and (3) heart rate (63.2%). The coronary vascular response to behavioral stress consisted of an initial late diastolic decrease in CBF (12.5%) between 5 and 10 seconds after conditional stimulus onset, followed by a significant increase in CBF (96.8%). Concurrently, late diastolic coronary vascular resistance (CVR) first significantly increased (21.9%), then significantly decreased (39.8%). The increase in CVR was attenuated by cardiac pacing and converted into a significant decrease after alpha-receptor blockade. The decrease in CVR was reduced either by cardiac pacing or cardioselective beta-receptor blockage and eliminated by the combination of alpha- and beta-receptor blockade. Thus, these data indicate that the coronary vascular response to stress consisted of two components: an initial alpha-adrenergic coronary vasoconstriction, followed by a more complex vasodilation which was probably mediated by metabolites released secondarily to increases in heart rate and inotropic state.

This article has been cited by other articles:

				J. A. Kovach, B. D. Nearing, and R. L. Verrier Angerlike behavioral state potentiates myocardial ischemia-induced T-wave alternans in canines J. Am. Coll. Cardiol., May 1, 2001; 37(6): 1719 - 1725. [Abstract] [Full Text] [PDF]