125I-Labelled tetanus toxin as a neuronal marker in tissue cultures derived from embryonic CNS

Primary cultures derived from embryonic mouse brain and spinal cord were exposed to 125I-labelled tetanus toxin and subjected to autoradiography. Cells with neuronal, but not glial, morphology selectively accumulated the toxin. The distribution of the grains over these cells and their processes was not uniform, discrete processes showing heavier labelling.