Acetylcholine operated ion channel and alpha-bungarotoxin binding site in a human neuroblastoma cell line reside on different molecules

In neurons, alpha-bungarotoxin is often associated with nicotinic receptor but does not always block the acetylcholine operated channel. In a human neuroblastoma cell line, IMR 32, we have demonstrated a large number of alpha-Bungarotoxin binding sites (2640 per cell in non differentiated cells and 4660 per cell in differentiated cells) in presence of 0 to 4 Acetylcholine activated-channels per cell. This neuronal cell line promises to be an useful model for the study of structure and function of the alpha-Bungarotoxin binding site not related to the nicotinic receptor.