Ischemic preconditioning inhibits glycolysis and proton
productionin isolated working rat hearts.
Finegan, Barry A., Gary D. Lopaschuk, Manoj Gandhi, and Alexander S.
Clanachan.
Departments of Anaesthesia and Pharmacology, Faculty of Medicine,
University of Alberta, Edmonton, Alberta, CANADA T6G 2H7
APStracts 2:0243H, 1995.
The effect of ischemic preconditioning (IPC) on glycolysis, glucose
oxidation, adenine nucleotide and nucleoside levels and mechanical
function was studied in isolated paced working rat hearts under
aerobic conditions or when reperfused following sustained ischemia.
IPC inhibited glycolysis (molmin-1g dry wt- 1) in aerobic hearts
(4.48+/-0.66 vs 3.18+/-0.39) and calculated proton production
attributable to exogenous glucose (7.79+/-1.31 vs 4.73+/-0.81). In
hearts subject to ischemia and reperfusion, IPC decreased, relative
to controls, glycogen content (moldry wt-1) prior to the onset of
ischemia (116.6+/-4.3 vs 158.0+/-8.4) and consumption of glycogen
during ischemia (54+/-6 vs 76+/-7). During reperfusion, glycolysis
(molmin-1g dry wt-1) was lower in IPC hearts (2.45+/-016 vs 4.4+/
-0.46), as was calculated proton production (3.57+/-0.30 vs 8.38+/
-0.93). Glucose oxidation was similar in control and IPC hearts.
Adenosine and ATP content (molg dry wt-1) of IPC hearts, relative to
controls, were higher at the end of ischemia being 0.86+/-0.08 vs
0.34+/-0.15 and 11.3+/- 0.8 vs 5.0+/-1.6, respectively. IPC enhanced
recovery of ventricular work during reperfusion of ischemic hearts
from 37% to 68%. These results indicate that IPC is associated with a
reduction in glycogen content, inhibition of glycolysis during
ischemia and reperfusion and a decrease in proton production for
glucose. These changes may, in part, explain the enhanced recovery of
mechanical function observed in IPC hearts.
Received 17 January 1995; accepted in final form 1 June 1995.
APS Manuscript Number H40-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.