[Properties of the sodium channels of the membrane of neuroblastoma clone N18 A-1 cultured cells].
Ionic currents through sodium channels of dialyzed mouse neuroblastoma N18 A-1 cells were measured under voltage clamp conditions. The PNa/PK ratio evaluated by reversal potential shifts was 10.4 +/- 0.7. Parameters of steady-state fast inactivation curves (h--V) and peak sodium conductance curves (gNa--V) were determined. The inactivation kinetics had usually a two-exponential time course. The internal perfusion of cells by trypsin and pronase caused a slowing-down of the sodium current falling  phase, pronase being more specific in this respect. An external application of the purified scorpion toxin in concentration of 1.42 X 10(-7) M leads to a fast and sharp slowing-down of sodium inactivation. The same toxin in concentration of 5 X 10(-6) M, applied internally was quite unaffective. Experimental results demonstrate similarities in the main features between the sodium channels of neuroblastoma cells and those of other excitable cell membranes.
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002999:Clone Cells / Q000378:metabolism; D003956:Dialysis; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009374:Neoplasms, Experimental / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D007473:Ion Channels; D012964:Sodium
Nekotorye svoĭstva natrievykh kanalov membrany kul'tiviruemykh kletok neĭroblastomy klona N18 A-1.