TRANSIENT ENHANCEMENT OF CHOLINERGIC NEUROCHEMICAL MARKERS INDUCED BYNGF IN AGED F344 RATS

Two experiments were conducted to assess the durability of nerve growt h factor (NGF) effects on cholinergic neurochemical markers. Artificia l CSF or NGF was infused via osmotic pumps for 2 weeks into the latera l ventricles of young adult (3- to 6-month-old) and aged (22- to 26-mo nth-old) Fischer 344 rats. Assessment of choline acetyltransferase (CA T) and acetylcholinesterase (AChE) within the cortex, striatum, and hi ppocampus was conducted either approximately 3 (experiment 1) or 12 (e xperiment 2) weeks after termination of treatment. A variety of age-re lated deficiencies were found in the two experiments with decreased ma rker levels within the dorsal hippocampus and striatum being most cons istent. NGF increased cholinergic marker enzyme activity in experiment 1 only. Specifically, NGF (a) attenuated age-related CAT and AChE def icits within the dorsal hippocampus and striatum, (b) enhanced CAT act ivity within the frontal cortex and ventral hippocampus in aged animal s, and (c) increased CAT activity within the dorsal hippocampus in you ng subjects. It is concluded that NGF may be beneficial in enhancing c holinergic neurochemical parameters, especially in aged animals, but s uch effects are most likely transient.