CHANGES IN CORTICAL EEG AND CHOLINERGIC FUNCTION IN RESPONSE TO NGF IN RATS WITH NUCLEUS BASALIS LESIONS

We examined whether recovery of cholinergic function in response to ne rve growth factor (NGF) results in restoration of electrocortical acti vity. Rats received unilateral lesions of the nucleus basalis and were infused intracerebroventricular (i.c.v.) over 3 weeks with NGF or veh icle. Cortical electrical activity was assessed at postoperative days 4, 7, 14, and 21 from 8 epidural electrodes. On day 21, choline acetyl transferase (ChAT) activity was measured in cortical tissue underlyin g each electrode site. Lesions resulted in increases in slow-wave (Del ta) power and decreases in high-frequency (beta(2)) powers in the lesi oned, as well as the non-lesioned hemisphere. Changes correlated topog raphically and in magnitude with losses of ChAT activity and suggested that regional electrocortical function was affected by cholinergic ac tivity originating in the ipsilateral, as well as the contralateral he misphere. NGF attenuated changes in cholingeric and electrocortical fu nction bilaterally, though in the lesioned hemisphere, function did no t return to control levels. Likewise, intact animals receiving NGF sho wed increases in beta(2)-power, as well as modest increases in ChAT ac tivity. Changes in brain electrical activity in response to NGF occurr ed within 4-7 days without significant changes during the 2 weeks ther eafter. Our results suggest that outcomes of future animal and human t rials unilateral i.c.v. infusions of NGF need to consider the reciproc al influences of hemispheric cholinergic function, as well as possible effects of NGF on intact brain. (C) 1997 Elsevier Science B.V.