Ischemic preconditioning accelerates ischemic contracture and high energy phosphate depletion in the blood perfused rat heart. Kolocassides, Kyriacos G., Manuel Gali[tilde]nanes, David J. Hearse. Cardiovascular Research, The Rayne Institute, St Thomas' Hospital, London SE1 7EH, UK.
APStracts 2:0219H, 1995.
We investigated the effect of preconditioning on the ischemia-induced depletion of ATP in the blood-perfused rat heart. Isolated hearts (n=5/group) were aerobically perfused with whole blood from a support rat and subjected to zero flow global ischemia (37 degrees C) for periods up to 35min. Frozen hearts were taken for metabolic analysis. Ischemic contracture was assessed with an isovolumic intraventricular balloon. The study groups were: (i) control (C) with unprotected ischemia, (ii) PC (two cycles of 3min ischemia/3min reperfusion) and (iii) cardioplegia (St Thomas') prior to ischemia. Preconditioning accelerated whilst cardioplegia delayed ischemic contracture (time -to-peak contracture PC=8.1+/-0.3min and CP=25.1+/-0.2min v C=15.6+/ -0.3min, P<0.05). The ischemia-induced decline in ATP was delayed by cardioplegia but accelerated by preconditioning (P<0.05). In a parallel study, preconditioning and cardioplegia protected post -ischemic contractile function to a similar extent. Thus, in the blood-perfused rat heart preconditioning accelerated ischemic contracture and depletion of ATP. In contrast, cardioplegia slowed ischemic contracture and ATP depletion. 

Received 9 January 1995; accepted in final form 12 May 1995.
APS Manuscript Number H19-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 May 1995.