Differential morphologic effects of two fractions from fetal calf muscle on cultured chick ciliary ganglion cells.

An extract of fetal calf striated muscle was found to support the survival, growth and differentiation of chick ciliary ganglion neurons in dissociated cell culture. The active material was precipitated in a single fraction by 35-60% ammonium sulfate. When this active fraction was passed over a concanavalin A-Sepharose column, only a portion of the activity was bound to the column and could be eluted by high salt. Both the bound and unbound fractions supported long-term neuronal survival and enhanced the neurons' capacity for acetylcholine synthesis. The two active fractions induced distinctly different morphologies in the cultures. The bound, salt-eluted fraction resulted in the extension of long, narrow multiply branched neurites with frequent varicosities, but it failed to support non-neuronal survival. The unbound, flow-through fraction caused the neurons to extend processes which aligned with each other and with the non-neuronal cells in dense networks. Striated muscle may thus possess the capacity to send more than one signal to modulate the development as well as maintain the survival of motor neurons.