NERVE GROWTH-FACTOR DOES NOT INFLUENCE THE EXPRESSION OF BETA-AMYLOIDPRECURSOR PROTEIN MESSENGER-RNA IN RAT-BRAIN - IN-VIVO AND IN-VITRO STUDIES

We investigated the effect of NGF on amyloid precursor protein (APP) m RNA levels in the rat septal/nucleus basalis system. Total APP mRNA an d APP 695 mRNA were determined in basal forebrain primary cell culture s exposed acutely and chronically to NGF (150-300 ng/ml) and, in vivo, in the septal area and striatum of rat pups after multiple intracereb roventricular injections of NGF. The trophic factor was able to affect cholinergic neurons in both paradigms, as evidenced by the significan t increase of choline acetyltransferase (ChAT) activity induced by NGF in cell cultures (+80%) and in the striatum (+240%) of rat pups. In s pite of this effect, no significant change of APP mRNA expression was observed in neuronal cultures and brain tissues. These data indicate t hat the neurotrophic effect of NGF on forebrain cholinergic neurons is not always associated with an alteration of APP expression.