NERVE GROWTH-FACTOR INCREASES EXTRACELLULAR ACETYLCHOLINE LEVELS IN THE PARIETAL CORTEX AND HIPPOCAMPUS OF AGED RATS AND RESTORES OBJECT RECOGNITION

Male Wistar rats (3- and 20-month-old) were perfused i.c.v. with 1.5 m u g of either nerve growth factor (NGF) or cytochrome C daily for 14 d ays. At the end of the infusion, the object-recognition test was carri ed out and extracellular acetylcholine levels (ACh) were measured in t he cortex and hippocampus by transversal microdialysis technique. In 2 0-month-old control rats, the cortical and hippocampal ACh levels were 35 and 45% lower, respectively, than in 3-month-old rats and the abil ity to discriminate between a familiar and new object was impared. In the old rats treated with NGF, the ACh release as well as the behavior al performance showed no difference from those of young rats. These fi ndings indicate that both ACh levels and memory impairment are improve d in aged rats by NGF treatment and suggest that there is a relationsh ip between object recognition and the activity of the forebrain cholin ergic system.