Polyamine biosynthesis is required for survival of sympathetic neurons after axonal injury.

Treatment of adult rats with specific inhibitors of polyamine synthesizing enzymes prevented the early increase in ornithine decarboxylase activity and polyamine content in the superior cervical ganglion after the postganglionic nerve was cut. Moreover, after axotomy, this treatment led to a marked diminution of the chromatolytic response with a marked neuronal cell death. We conclude that after axonal injury an early increase in polyamine biosynthesis, probably within parent sympathetic neurons, is an obligatory step in the progression of the axon reaction.