Inhibition of acetylcholine receptor synthesis by conditioned medium of electrically stimulated muscle cultures.

In previous studies, it has been reported that electrical stimulation of muscle cultures is followed by inhibition of acetylcholine receptor (AChR) synthesis. In the study reported here, we show that even media taken from electrically stimulated muscle cultures are capable of inhibiting receptor synthesis. This inhibition is specific, since the levels of acetylcholinesterase and creatine kinase are not reduced. The electrically stimulated myotubes probably synthesize and release to the medium a protein(s) responsible for reducing AChR synthesis.