Changes in glia-neuron relationships in cell cultures of spinal ganglia caused by puromycin.

Dorsal root ganglia of chick embryos were cultured for one to four weeks on Maximow-slides. Puromycin was added to cultures for a pulse of 30' in a dose of 100 mug/ml medium. Particular interest was given to the ultrastructural features of the glia-neuron relations. Puromycin caused a shrinkage of the glial processes and consequently the continous glial envelope of the spinal ganglion neurons disappeared. These changes of glia-neuron contacts were reversible after a few days when puromycin was withdrawn from the medium. The newly formed glial sheaths around the neurons were comparable to those in untreated cultures and to those in vivo. The effects of an inhibition of protein synthesis caused by puromycin are discussed in relation to the effects on the cell motility, on the renewal of cell membranes and on the formation of cell contacts in nervous tissue.