Synaptogenesis in cell cultures of neurones and myotubes from chickens with muscular dystrophy.

Intracellular microelectrode recordings from chick dystrophic myotubes in cell culture reveal a capability for innervation by neurones from either dystrophic or normal embryos. Neither neuronal class differentially affects the incidence of synapse formation at neuromuscular junctions (about 75%) or at neural junctions (about 85%), the PSP frequency (about 10/sec), the maximum quantal content at neuromuscular junctions (over 70), or the resting membrane potentials of either myotubes (about - 53 mV) or neurones (about - 43 mV). In each culture conditon about 20% of nerve-muscle cell pairs exhibit bidirectional electrical coupling. Dual innervation of a muscle and nerve cell from a common presynaptic source sometimes occurs and both muscle and nerve cells probably have multiple innervation. Assuming the capability for expression in culture of genetic differences between neurones from the dystrophic and normal chick, we conclude that these differences are not significant in the regulation of synapse formation in dystrophic chick nerve-muscle cell culture.