[The potential-dependent nature of the sodium pump of mollusk giant neuron membranes].
The effect of the membrane potential on the pump current induced by ionophoretic injection of sodium ions into the isolated and semiisolated neurons and the effect of sodium ions intracellular concentration on the potential dependence of the pump current were studied in snails Helix pomatia and Helix italiana. It is found in voltage clamp experiments that the pump current can reverse its direction under a sufficient membrane hyperpolarization (above--80 divided by --120 mV). Additional injections of sodium ions into the neuron increases the potential dependence of the pump current and facilitates the appearance of reversed pump current. It is supposed that this reversal may be due to activation of potassium permeability of the membrane coupled in some way with the acitvity of the enzymatic transport mechanism.
D000818:Animals; D001693:Biological Transport, Active; D002463:Cell Membrane Permeability; D006372:Helix, Snails / Q000502:physiology*; D008564:Membrane Potentials; D009474:Neurons / Q000502:physiology*; D012908:Snails / Q000502:physiology*; D012964:Sodium / Q000378:metabolism*
D012964:Sodium
Osobennosti potentsialozavisimosti toka natrievogo nasosa membrany gigantskikh neĭronov molliuskov