A Role for Neurotrophins in the Survival of Murine Embryonic Thalamic Neurons

The mechanisms that determine whether developing CNS neurons live or die are poorly understood. We studied the role of the neurotrophins and fibroblast growth factors in the survival of embryonic thalamic neurons in culture. Dissociated embryonic dorsal thalamic neurons cultured at high density in defined serum‐free medium survived and grew neurites. As in vivo, they expressed all the neurotrophins, fibroblast growth factor‐1 and their high‐affinity tyrosine kinase receptors. The survival of these cells was reduced by the addition of the protein kinase inhibitor K252a at concentrations that block neurotrophin receptor activity but not the activity of other tyrosine kinase receptors. In low‐density cultures, most dorsal thalamic neurons died, but their survival was increased by co‐culture with thalamic explants or with most of the neurotrophins and fibroblast growth factor‐1 added singly. These results indicate that thalamic neurons have remarkably promiscuous trophic responses to a battery of neurotrophins and fibroblast growth factors. They suggest that neurotrophins endogenous to the early embryonic thalamus may be required to promote the survival of its neurons.