In vitro survival of chick embryo spinal neurons capable of forming synapses on skeletal muscle cells.

Survival of chick embryo spinal neurons capable of forming synapses on skeletal muscle cells (junction-forming neurons) was examined electrophysiologically in culture. Tissue extracts (skeletal muscle, heart, liver, brain), serum-free muscle-conditioned medium, horse serum (HS), chick embryo extract (CEE) showed survival-promoting activity. The highest activity was observed in a mixture of HS and CEE. This mixture did not promote the survival of all of the spinal cord cells, but selectively supported the survival of junction-forming neurons.