Neuronal stimulation of non-neuronal (glial) cell proliferation: lack of specificity between different regions of the nervous system.

Purified and recombined primary cultures of neurons and non-neuronal (glial) cells were prepared from the cerebral hemispheres of 10-day chick embryos. Addition of cerebral neurons to homologous non-neuronal cultures stimulated incorporation of [3H]thymidine by 2.8-fold and increased the frequency of labelling of the non-neuronal cells by 3.5-fold as visualized by autoradiography. In contrast, cerebral neurons did not stimulate the proliferation of either embryonic chick fibroblasts or leptomeningeal cells. Furthermore, addition of either fibroblasts or extra non-neuronal cells did not stimulate non-neuronal cel proliferation. These data demonstrate for the first time that neurons isolated from the central nervous system can selectively stimulate the proliferation of homologous non-neuronal cells. Cell proliferation was also studied in cultures containing both homologous and heterologous combinations of neuronal and non-neuronal cells prepared from several different portions of the nervous system (cerebral hemispheres, optic lobes, sympathetic ganglia, and sensory ganglia). Addition of embryonic neurons stimulated non-neuronal cell proliferation in all cell combinations. Thus, neurons isolated from one region of the nervous system can stimulate the proliferation of non-neuronal cells isolated from other neural regions.