β-Bungarotoxin induction of neurite outgrowth in NB41A3 cells

In this study, different concentrations of β-Bgt were used to treat cultured NB41A3 cells. Inverted phase contrast microscopy was then used 24 h after treatment to observe the outgrowth of neurite. We found a clear outgrowth of neurite at β-Bgt concentrations of 357 nM. However, using a cytotoxicity assay to study apoptosis, we found no significant difference in the rate of cell death in cell cultures treated with either 357 nM or 714 nM. Western blotting showed that after treatment with β-Bgt, there was a notable decrease in small G protein Cdc42 and a marked increase in RhoA protein. Flow cytometry revealed that β-Bgt did not alter the calcium influx in NB41A3 cells. The neurite outgrowth induced by β-Bgt was not affected by extracellular EGTA, suggesting that the internalization of β-Bgt from extracellular was independent of phospholipase. Taken together, our results suggest the β-Bgt-induced outgrowth of neurite from NB41A3 cells may be mediated by small G proteins.