DEVELOPMENT AND DIFFERENTIATION OF CHICK CILIARY GANGLION CELLS IN CULTURE

Abstract

Publisher Summary The autonomic nervous system has provided a useful model for the study of development and differentiation of neurons. Sympathetic and parasympathetic ganglions consist of only a few kinds of nerve cells. Recently, the parasympathetic system has been studied using the chick ciliary ganglion in tissue culture. This ganglion contains two major neuronal cell types: choroid neurons—which establish cholinergic synapses on smooth muscle in the choroid layer—and ciliary neurons—which form cholinergic synapses on striated muscle in the iris. Therefore, this offers an enriched source of cholinergic neurons for the study of nerve-muscle interactions. In addition, it has been documented that chick ciliary ganglion form functional synaptic connections with muscle cells in culture. Conditioned medium (CM) from the cultures of muscle, glioma, and heart fibroblasts promotes the outgrowth of neurites in expiants and dissociated cells from ciliary ganglion cultures, whereas nerve growth factor has no effect. This growth factor has been characterized from the muscle and glioma CM. The forms of acetylcholinesterase in co-cultures of chick muscle and ciliary ganglion, have been examined. However, no evidence has been found that the heavy form of the enzyme can be used as a biochemical marker for synapse formation.