Single acetylcholine-activated channels in cultured rhabdomyoblasts.

Acetylcholine receptor (AChR) was found to be present on the cell surface of the human rhabdomyoblast (RD) cell line. Two classes of ACh-activated channels have been observed, one with a large conductance and long duration and the other with smaller conductance and short duration, similar to those of human myotubes. RD membrane exhibited a specific binding to the alpha-bungarotoxin indicating the presence of nicotinic AChRs. These results support the hypothesis that rhabdomyosarcomas derive from myogenic precursors.