Age-related variations in plasticity of rat basal forebrain cholinergic neurons after cortical lesions

The enzymatic activity of choline acetyltransferase (ChAT) in the nucleus basalis (NBM) of young rats (30 days old at the time of the operation) drops by 50% thirty days after cortical damage. This is followed by a spontaneous recovery of the enzymatic activity at 120 days after the lesion. In the present study, similar changes were observed in rats which were lesioned at maturity (4 months old). However, a different response was noted when surgery was performed on aged rats (2 years old at the time of operation). In these aged rats the drop in enzymatic activity in the NBM at 30 days post-lesion was as marked as in the young and mature animals, and no recovery was observed, even at 120 days. These results are discussed in the context of age-related neurodegenerative disease with cholinergic involvement.