Damage to the NBM leads to a sustained lesion-induced increase in functional NGF in the cortex

Bilateral infusions of colchicine or vehicle were made in the nucleus basalis magnocellularis of rats. Cortical homogenates were assessed in a choline acetyltransferase (ChAT) activity assay and a PC12 cell neurite outgrowth assay 3, 7, 14, 28, 35 or 84 days post-lesion. Cortical ChAT activity was initially decreased by 30%, followed by recovery to control levels at 84 days post-lesion. Cortical nerve growth factor (NGF) activity was increased 35% above control levels at all time points following colchicine infusion, while addition of a NGF antibody blocking all activity. The data show an increase in functional NGF in the target area of the lesioned neurons preceding and coinciding with regional recovery of a cholinergic marker, suggesting that NGF has a role in the cholinergic recovery.