[Sodium and calcium channels of the somatic membrane of neuroblastoma cells during artificially induced differentiation].

Sodium and calcium channels passing inward currents were studied by intracellular dialysis technique and voltage clamp in the somatic membrane of neuroblastoma cells during their morphological differentiation induced by increasing pH of the culture medium up to 8.0-8.2. Kinetic and voltage-dependent properties of sodium and calcium channels of differentiated cells and cells grown in the suspension culture were identical. Densities of sodium currents in the somatic membrane of neuroblastoma cells grown in suspension culture were about 7.3 +/- 0.8 microA/microF and from 37 +/- 5.2 microA/microF to 54.7 +/- 3.6 microA/microF of differentiated cells at different terms of cultivation. Densities of calcium currents in the membrane of cells grown in suspension were about 1.4 +/- 0.2 microA/microF, while in differentiated cells they ranged from 1.1 +/- 0.2 to 2.8 +/- 0.4 microA/microF at different terms of cultivation. Induction or reduction of differentiation by varying pH of the culture medium produced reciprocal changes in densities of sodium and calcium channels.