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 neu rite 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 point s following colchicine infusion, while addition of a NGF antibody bloc king all activity. The data show an increase in functional NGF in the target area of the lesioned neurons preceding and coinciding with regi onal recovery of a cholinergic marker, suggesting that NGF has a role in the cholinergic recovery.