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Regulation of Cardiac Sarcolemmal Na + /H + Exchanger Activity by Endogenous Ligands: Relevance to Ischemia a
Author(s) -
AVKIRAN METIN,
HAWORTH ROBERT S.
Publication year - 1999
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1999.tb09249.x
Subject(s) - sarcolemma , sodium–hydrogen antiporter , intracellular ph , intracellular , chemistry , endogeny , extracellular , ischemia , acidosis , myocyte , biophysics , biochemistry , medicine , membrane , sodium , biology , organic chemistry
A bstract : The cardiac sarcolemmal Na + /H + exchanger (NHE) extrudes one H + in exchange for one Na + entering the myocyte, utilizing for its driving force the inwardly directed Na + gradient that is maintained by the Na + /K + ATPase. The exchanger is quiescent at physiological values of intracellular pH but becomes activated in response to intracellular acidosis. Recent evidence suggests that a variety of extracellular signals (e.g., adrenergic agonists, thrombin, and endothelin) also modulate sarcolemmal NHE activity by altering its sensitivity to intracellular H + . Since sarcolemmal NHE activity is believed to be an important determinant of the extent of myocardial injury during ischemia and reperfusion, regulation of exchanger activity by endogenous ligands associated with ischemia is likely to be of pathophysiological importance.