Steady‐state contribution of the sodium pump to the resting potential of a molluscan neurone
- 1 October 1974
- journal article
- Published by Wiley in The Journal of Physiology
- Vol. 242 (1), 35-48
- https://doi.org/10.1113/jphysiol.1974.sp010692
Abstract
1. The electrogenic contribution of the Na(+)-K(+) exchange pump to the membrane potential of the Anisodoris giant neurone (G cell) was examined under steady-state and Na(+) loaded conditions.2. The membrane potential was variable for the first 1-4 hr after impalement, but, in the absence of experimental manipulation, remained constant thereafter. The average membrane potential for ten cells maintained at 11-13 degrees C and measured 5-36 hr after impalement was 55.8 +/- 1.0 mV (S.E. of mean).3. Low concentrations of external ACh caused a reversible increase in membrane Na(+) conductance. Brief exposure to ACh proved a fast and reversible technique to load the cell with Na(+) ions, and transiently stimulate the electrogenic Na(+) pump.4. In ten cells maintained from 5 to 36 hr at 11-13 degrees C the reduction in membrane potential produced by inhibition of the Na(+) pump with ouabain was remarkably constant between cells and averaged + 9.7 mV.5. Cells maintained under steady-state conditions (at 11-13 degrees C) for extended periods of time were shown to be relatively insensitive to changes in temperature and to small changes in external K(+).6. It is estimated that the Na(+)-K(+) exchange pump contributes approximately - 10 mV to the steady-state resting potential of the G cell, and that two Na(+) ions are extruded for every K(+) ion transported into the cell per pump cycle.Keywords
This publication has 20 references indexed in Scilit:
- Post‐stimulus hyperpolarization and slow potassium conductance increase in Aplysia giant neuroneThe Journal of Physiology, 1972
- The independence of electrogenic sodium transport and membrane potential in a molluscan neuroneThe Journal of Physiology, 1971
- The effects of temperature and ions on the current—voltage relation and electrical characteristics of a molluscan neuroneThe Journal of Physiology, 1971
- Axonal Localization of An Excitatory Post-Synaptic Potential in A Molluscan NeuroneJournal of Experimental Biology, 1970
- An Investigation of the Electrogenic Sodium Pump in Snail Neurones, Using the Constant-Field TheoryJournal of Experimental Biology, 1969
- The stoicheiometry of the sodium pumpThe Journal of Physiology, 1967
- Temperature Effects on Pacemaker Generation, Membrane Potential, and Critical Firing Threshold in Aplysia NeuronsThe Journal of general physiology, 1967
- The effect of ions on the membrane potential of snail neuronesComparative Biochemistry and Physiology, 1967
- Effect of nerve impulses on the membrane potential of glial cells in the central nervous system of amphibia.Journal of Neurophysiology, 1966
- The connexion between active cation transport and metabolism in erythrocytesBiochemical Journal, 1965