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Intracellular pH Regulation and Myocardial Ischemia-Reperfusion Injury

  • Danielle Feuvray
Part of the Progress in Experimental Cardiology book series (PREC, volume 1)

Abstract

Changes in cellular cation homeostasis figure prominently in the pathogenesis of cellular damage during ischemia and reperfusion. With respect to the functional alterations related to reperfusion of the ischemic heart, it is now recognized that reactivation of the Na+-H+ exchange (NHE) following ischemia-induced acidosis plays a key role in the development of such alterations. Na+-coupled acid extrusion via Na+:linked HCO3 influx also contributes to the recovery of pHi after ischemia. In this context, the diabetic rat heart appears to be an interesting model, since a significant decrease in NHE activity has been shown to be associated with this pathological state. In diabetic myocytes, the acid efflux carried by NHE following an acid load was markedly decreased (for example, a 42% reduction at pHi 6.9 when compared to normal). On the contrary, acid efflux carried by the Na+-linked HCO3 influx remained nearly identical in both normal and diabetic cells. As a consequence, the marked decrease in total acid efflux from the diabetic myocytes essentially results from the significant decrease in NHE activity. This depressed NHE activity may afford some protection against ischemia-reperfusion injury. A protection was indeed observed in perfused hearts isolated from diabetic rats, in which there was a markedly improved recovery of contractility following ischemia, comparable to that obtained with a pharmacological block of NHE, as compared to normal hearts. This outcome was associated with a markedly slower pHi recovery.

Keywords

Diabetic Heart Acid Efflux Sheep Cardiac Purkinje Fibre Diabetic Myocytes Cardiac Sarcolemmal Vesicle 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Danielle Feuvray
    • 1
  1. 1.Laboratoire de Physiologic CellulaireFrance

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