Cyclic AMP regulates the life time of acetylcholine-activated channels in cultured myotubes.

'Giga-seal' patch-clamp recording was performed in embryonic chick myotubes at day 3 to 4 of culture. Myotubes were exposed to agents that enhance the concentration of cytosolic cyclic AMP (cAMPi) and their action on acetylcholine- (ACh) activated channels was investigated. While the conductance and the closed time was unaffected by forsokolin, cholera toxin, dibutyryl cyclic AMP and 8-bromo-cyclic AMP, these agents lengthened the ACh-activated channel life time with efficacy that paralleled with their capability to increase the cAMPi.