Substance P counteracts neurotoxin damage on norepinephrine neurons in rat brain during ontogeny.

Systemic treatment of newborn rats with the catecholamine neurotoxin 6-hydroxydopamine alters the postnatal development of the central norepinephrine neurons. The changes are permanent and consist of denervation of distant nerve terminal projections (for example, cerebral cortex) and hyperinnervation of terminal areas close to the cell bodies (for example, cerebellum). Intracisternal injection of substance P counteracted both of these alterations. The results indicate that substance P may prevent degeneration of damaged norepinephrine neurons during ontogeny or may have a regrowth stimulatory action on these cells. Substance P might prove of use in the prevention or reduction of other types of neurodegenerative disease.