The effect of neurobiotin on membrane properties and morphology of intracellularly labeled neurons

Abstract

The effect of neurobiotin on membrane properties and morphology of rat neostriatal neurons were investigated with intracellular recording and staining techniques in vivo. Using electrodes filled with 3% neurobiotin in 2 M potassium acetate, no significant changes in membrane properties were observed if iontophoresis was performed for 15 min with 0.5 nA depolarizing current pulses. If the current was greater than 1nA, the spike width was significantly increased. The spike width was also significantly increased if the electrode was maintained in the cell for more than 30 min without current injection. With electrodes containing 2 M potassium acetate alone, no significant change was observed on spike width after 1 nA current injection, suggesting that the change was caused by the neurobiotin. The recovery rate of labeled neurons decreased with increasing survival period. The recovered neurons were strongly stained 12 h after labeling and faded significantly by 48 h. No signs of degeneration were observed in any labeled neurons. The present study indicates that neurobiotin has no significant effects on membrane properties except for increased spike width of the recorded neurons. Neurons can be recovered up to 48 h after intracellular staining with neurobiotin.