NERVE GROWTH-FACTOR PROMOTES SURVIVAL OF CULTURED MAGNOCELLULAR CHOLINERGIC NEURONS FROM NUCLEUS BASALIS OF MEYNERT IN POSTNATAL RATS

One of the possible causes of Alzheimer''s disease is thought to be a lack of nerve growth factor (NGF), which plays an important role in the neuronal differentiation and cell survival of basal forebrain cholinergic neurons. In the present study, we report for the first time a direct in vitro effect of NGF on the survival of magnocellular cholinergic neurons of the nucleus basalis of Meynert. A dissociated culture of cholinergic neurons was prepared after dissecting out the nucleus from vibratome slices of postnatal rat forebrain. After culturing the neurons of this nucleus from 2-week-old rats for 6 days, the cell number of viable acetylcholinesterase-positive cholinergic neurons in the presnce of NGF was found to be greater than that in the absence of NGF. Also, more extensive and denser acetylcholinesterase-positive neurites were observed in the NGF-treated culture. Higher activities of choline acetyltransferase were also observed in the NGF-treated culture. Cellular choline acetyltransferase activity, which was calculated by dividing the enzyme activity by the viable number of acetylcholinesterase-positive neurons for each well, was almost the same with or without NGF. These results mean that NGF enhanced cholinergic neuronal survival and cholinergic neurite regeneration, but did not induce cellular choline acetyltransferase activities.