Comparative studies on the effect of the nerve growth factor on sympathetic ganglia and adrenal medulla in newborn rats

Abstract The effect of nerve factor (NGF) and nerve growth factor antiserum (NGF-AS) on sympathetic ganglia and adrenal chromaffin cells of newborn rats was investigated in a comparative study. In confirmation of previous experiments, NGF had a marked hypertrophic and hyperplastic effect in sympathetic ganglia. These morphological changes were accompanied by a selective induction of tyrosine hydroxylase and dopamine β-hydroxylase. The biochemical correlate with the degenerative changes elicited by NGF-AS in sympathetic ganglia was a reduction of all enzymes studied that are located in adrenergic neurones. In the adrenal medulla neither NGF nor NGF-AS produced any detectable morphological changes. However, both procedures resulted in a statistically significant increase in tyrosine hydroxylase and dopamine β-hydroxylase. The paradoxical finding that both NGF and its antiserum produce the same effect on the adrenal chromaffin cells is most plausibly explained by the assumption that both treatments elicit a stress-induced increase in the activity of splanchnic nerves supplying the adrenal medulla, and to a consequent neurally mediated induction of these key enzymes involved in the synsthesis of the adrenergic transmitter, as they do in adult animals under various experimental conditions that lead to an increased activity of the sympathetic nervous system.