Contributions of the sodium pump and ionic gradients to the membrane potential of a molluscan neurone
A. L. F. Gorman,M. F. Marmor +1 more
TLDR
The membrane potential of the gastro‐oesophageal giant neurone of the marine mollusc, Anisodoris nobilis, was examined during changes of temperature and of the ionic medium.Abstract:
1. The membrane potential of the gastro-oesophageal giant neurone of the marine mollusc, Anisodoris nobilis, was examined during changes of temperature and of the ionic medium.2. The response of the membrane potential to rapid changes in the external K concentration was prompt, stable, and reversible up to 200 mM-K, and was independent of the external Cl concentration.3. Warming the cell produced a prompt hyperpolarization that was approximately 10 times greater than predicted by the Nernst or constant field equations. Electrogenic activity of the Na-K exchange pump was shown to be responsible for this effect.4. At temperatures below 5 degrees C, the relationship between the membrane potential and the external K concentration could be predicted by a constant field equation.5. At temperatures above 5 degrees C, the membrane potential could not be predicted by the constant field equation except after inhibition of the electrogenic Na pump with ouabain or the reduction of internal Na.6. Inhibition of the electrogenic Na pump by low external K concentrations was dependent upon the external Na concentration.7. It is concluded that the membrane potential is the sum of ionic and metabolic components, and that the behaviour of the ionic component can be predicted by a constant field type equation.read more
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References
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Journal ArticleDOI
Sodium Fluxes in Internally Dialyzed Squid Axons
F. J. Brinley,L. J. Mullins +1 more
TL;DR: Nine naturally occurring high energy phosphate compounds were ineffective in supporting significant sodium extrusion and there was no evidence of saturation of efflux even at internal ATP concentrations of 10,000 µM, while the relation between internal sodium and sodium efflux was linear.
Journal ArticleDOI
Membrane potential changes during sodium transport in frog sartorius muscle.
TL;DR: The idea that a potassium ion might be transported into the cell for each sodium ion actively extruded, leading to an electrical neutrality with respect to the operation of the sodium-pump, has been tested in the following experiments.
Journal ArticleDOI
Analysis of slow inhibitory postsynaptic potential of bullfrog sympathetic ganglion.
Journal ArticleDOI
The influence of potassium, sodium and chloride on the membrane potential of the smooth muscle of taenia coli.
Journal ArticleDOI
Synaptic activation of an electrogenic sodium pump.
Harold Pinsker,Eric R. Kandel +1 more
TL;DR: An identified molluscan interneuron mediates different cholinergic synaptic actions by increasing the conductance of its follower cells to different ions but also mediates a new class of synaptic actions which does not involve a conductance change but the activation of an electrogenic sodium pump.
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