Reparative processes in aged brain

Endogenous neurotrophic factors have been proposed to play an important role in degenerative diseases and aging. In aged rats, neurotrophic activity induced by partial lesion of nigro-striatal pathways seems to be lower compared to young rats when assayed in vitro on cultured mesencephalic dissociated neuronal cells. In parallel experiments, we could also observe an age-dependent delay in spontaneous recovery of striatal tyrosine hydroxylase activity after lesion. Both experimental evidences suggest a low-potential neuroplasticity in aged rats. Nevertheless, the aging brain seems to be responsive to pharmacological manipulation. Long-term phosphatidylserine treatment has been shown to maintain the integrity of neuronal structures altered by the aging process. Putative mechanisms of action underlying these effects are presented.