Potassium current in clonal cytotoxic T lymphocytes from the mouse.
The electrical properties of the cell membrane of clonal cytotoxic T lymphocytes in the mouse were studied by using the whole cell variation of the patch electrode voltage-clamp technique. Outward currents were activated with an exponential time course of several milliseconds time constant when the membrane potential was made more positive than -50 to -40 mV. This current is not activated as a result of Ca2+ entry. The estimated reversal potential of the current indicates that the current is predominantly carried by K+. The activation kinetics depend only on membrane potential, not on [K+]0. The amplitude of the current decreases exponentially with time constants of several hundred milliseconds during a maintained voltage pulse, due mainly to a decrease in conductance. Recovery from inactivation roughly followed a single exponential time course with a time constant of tens of seconds; this time constant depended upon not only the membrane potential but also the amount of initial inactivation. The current is suppressed by quinidine and tetraethylammonium, their half-suppression concentrations being 23 microM and 14 mM respectively. An increase of the outward current is suggested to be associated with the lethal hit of the cytotoxic reaction.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002478:Cells, Cultured; D002999:Clone Cells / Q000502:physiology; D004553:Electric Conductivity; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D011188:Potassium / Q000502:physiology*; D011802:Quinidine / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000502:physiology*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013997:Time Factors
D013757:Tetraethylammonium Compounds; D019789:Tetraethylammonium; D008274:Magnesium; D011802:Quinidine; D011188:Potassium