Decrease of potassium permeability by intracellular application of sodium ions in snail neurons.
In the identified neurons B1, B2 and B3 of Helix pomatia an intracellular injection of Na+ induced an outward current in 10% and an inward current in 90% of the experiments. The outward current was associated with an increase and the inward current with a decrease of the membrane conductance. Both currents reversed at membrane potentials of between -60 and -70 mV. Inward currents were also elicited by intracellular Li+ or tris-[hydroxymethyl]-aminomethane (Tris+) injection. All inward currents were reduced by extracellular administration of tetraethylammonium or quinine. It is suggested that the outward current represents a calcium-activated potassium current and that the inward current is due to a blockade of potassium channels from the intracellular side.
J
J
Walden
O W
OW
Witte
E J
EJ
Speckmann
D000818:Animals; D002118:Calcium / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects*; D003864:Depression, Chemical; D005724:Ganglia / Q000378:metabolism*; D006372:Helix, Snails; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D008094:Lithium / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology*; D014325:Tromethamine / Q000494:pharmacology
D007473:Ion Channels; D014325:Tromethamine; D008094:Lithium; D012964:Sodium; D011188:Potassium; D002118:Calcium