The FASEB Journal, Vol 3, 1963-1967, Copyright © 1989 by The Federation of American Societies for Experimental Biology

RESEARCH COMMUNICATIONS

Metabolites of the glycolytic pathway modulate the activity of single cardiac Na+ channels

M Kohlhardt, H Fichtner and U Frobe
Physiological Institute, University of Freiburg, Federal Republic of Germany.

Elementary Na+ currents through single cardiac Na+ channels were recorded at 19 degrees C in patch clamp experiments with cultured neonatal rat cardiocytes. The metabolites of the glycolytic pathway, 2,3-diphosphoglycerate and glyceraldehyde phosphate, were identified as a novel class of modulators of Na+ channel activity. In micromolar concentrations (1-10 mumol/liter), their presence at the cytoplasmic membrane face increased the number of sequential openings during depolarization and prolonged the conductive channel state. As found after ensemble averaging, the decay kinetics of reconstructed macroscopic Na+ currents became retarded and slow Na+ inactivation may have been evoked. Both metabolites attenuated the rundown of channel activity that regularly develops after patch excision in the inside-out patch configuration. It is tempting to assume that interference with Na+ inactivation is the mode of action underlying the increase in single-channel activity.

This article has been cited by other articles:

				M. Garcia-Fernandez, P. Ortega-Saenz, A. Castellano, and J. Lopez-Barneo Mechanisms of Low-Glucose Sensitivity in Carotid Body Glomus Cells Diabetes, December 1, 2007; 56(12): 2893 - 2900. [Abstract] [Full Text] [PDF]

				J. Kockskamper, A. V. Zima, and L. A. Blatter Modulation of sarcoplasmic reticulum Ca2+ release by glycolysis in cat atrial myocytes J. Physiol., May 1, 2005; 564(3): 697 - 714. [Abstract] [Full Text] [PDF]