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Investigation of the TEA-resistant outward current in the somatic membrane of perfused nerve cells

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Abstract

Outward currents remaining after addition of 20–50 mM of tetraethylammonium (TEA) ions to the extracellular or intracellular solution, were investigated in perfused isolatedHelix neurons. After this addition, the inactivated inward current carried by potassium ions, the potential-dependent and kinetic characteristics of which differ from those of potassium outward currents suppressed by TEA, is preserved in the membrane. A component dependent on the inward calcium current was found in this TEA-resistant outward current; it was abolished by replacement of the extra-cellular calcium ions by magnesium ions, by blocking of the calcium channels by extracellular cadmium ions, and by their destruction by intracellular fluoride ions. Increasing the intracellular concentration of free calcium ions by perfusing the cell with solutions containing calcium-EGTA buffer potentiated the TEA-resistant component of the outward current, whereas removal of these ions with EGTA weakened it. It is concluded that a system of outward current channels whose activation depends on the presence of calcium ions near the inner surface of the membrane is present in the somatic membrane. It is suggested that to keep these channels capable of being activated, calcium ions must bind with the structures forming their internal opening.

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Authors
  1. P. A. Doroshenko
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  2. P. G. Kostyuk
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  3. A. Ya. Tsyndrenko
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Additional information

A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 11, No. 5, pp. 460–468, September–October, 1979.

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Doroshenko, P.A., Kostyuk, P.G. & Tsyndrenko, A.Y. Investigation of the TEA-resistant outward current in the somatic membrane of perfused nerve cells. Neurophysiology 11, 341–348 (1979). https://doi.org/10.1007/BF01062997

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  • DOI: https://doi.org/10.1007/BF01062997

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