The effects of postganglionic axotomy and nerve growth factor on the superior cervical ganglia of developing mice.

Sectioning of the two major outflows from the superior cervical ganglia in two week mice results in a marked drop in the number of neurons within one week of operation and a smaller drop over the following two weeks. In animals receiving daily injections of nerve growth factor (NGF), the effect of axotomy is modified. One week after axotomy, the number of neurons in the axotomized ganglia is approximately the same in NGF treated animals as in the control, sham operated ganglia. Over the next two weeks, however, the cell death that results from axotomy is no longer prevented by treatment with NGF. The normal, hyperplastic response to NGF appears to occur independently of the cell reaction caused by axotomy.