Effects of nerve growth factor from the venom of Vipera russelli on dispersed sensory ganglion cells from the embryonic chick.

A quantitative study has been made of the effects of nerve growth factor (NGF), isolated from the venom of Vipera russelli, on the growth of dispersed cells from the sensory ganglia of the embryonic chick. The main effects were to increase the viability of the sensory neurons in culture and to promote the regeneration of nerve fibres. In the presence of NGF a higher proportion of neurons produced fibres and the fibres were longer and slightly more branched than in control cultures. The number of fibres produced per neuron was unaltered. Supporting cells were unaffected by the presence of NGF. No stimulation of mitotic activity among either type of cell was observed. It is concluded that, under the stated conditions, NGF does not promote the differentiation of immature cells but acts, both in a maintenance and a stimulatory capacity, only on those cells recognizable as neurons.