Hypothalamic Neurons in Dissociated Cell Culture: The Mechanism of Increased Survival Times in the Presence of Non-Neuronal Cells

Rat hypothalamic neurons were cultured in the presence of fluorodeoxyuridine to inhibit nonneuronal cell proliferation. Under these conditions, neuronal cell survival was dependent on contact with homologous nonneuronal cells. This phenomenon did not seem to be due to the release of diffusable trophic factors, since neither growth on polylysine in the close proximity of nonneuronal cells nor the use of preconditioned medium significantly increased neuronal survival. However, metabolically active cell layers were required, since growth on heat-killed or fixed homologous nonneuronal cells did not increase neuronal survival. The increased survival of neurons seen here in the presence of homologous nonneuronal cells therefore appears to be due to metabolic co-operation mediated by specific, direct cell-cell contact.