Human serum albumin enhances sodium currents in NH15-CA2 neuroblastoma x glioma hybrid cells.

The effect of human albumin on neuronal voltage-dependent Na+ channels was studied in NH15-CA2 neuroblastoma x glioma hybrid cells. At an albumin concentration of 32 g/l, the transient Na+ currents, elicited at 1 Hz and recorded with the whole-cell technique, were increased to 125% the control value. The effect was complete within 2-4 s of extracellular albumin application; 35 s after washout of the protein it was not yet fully abolished. The albumin effect is mediated by a shift of the voltage dependence of steady-state inactivation of the Na+ channels towards more positive potentials. The activation of the channels is not noticeably influenced.