AJP - Heart and Circulatory Physiology, Vol 239, Issue 5 614-H620, Copyright © 1980 by American Physiological Society
Performance of diabetic rat hearts: effects of anoxia and increased work
C. G. Ingebretsen, P. Moreau, C. Hawelu-Johnson and W. R. Ingebretsen Jr
An isolated perfused working rat heart preparation was used to assess the
effect of alloxan-induced diabetes on myocardial performance. Ventricular
performance was assessed under different aortic afterload,
isoproterenol-stimulated and anoxic conditions. Basal left ventricular
pressure development and rate of rise of ventricular pressure were
depressed in hearts from diabetic animals. Neither coronary flow nor
cardiac output were affected by diabetes. The dose and temporal responses
to an infusion of isoproterenol were unaltered in diabetic hearts.
Isoproterenol increased coronary flow by 50% and elevated ventricular
pressure, dP/dt, and cardiac output by two- to threefold. Anoxia depressed
ventricular pressure to below 20% of control within 5 min in both diabetic
and normal hearts. Reoxygenation after 10 min of anoxia produced equivalent
recovery in both groups working against a 52-mmHg aortic afterload, whereas
recovery after 20 or 30 min of anoxia, was depressed in diabetic hearts.
Elevating aortic afterload decreased performance of diabetic hearts and
decreased their ability to recover from a 10-min anoxic exposure. Many of
these observed differences in mechanical performance of diabetic hearts can
be overcome by high glucose or insulin in the perfusion media.
