ETHANOL REDUCES EXPRESSION OF THE NERVE GROWTH-FACTOR RECEPTOR, BUT NOT NERVE GROWTH-FACTOR PROTEIN-LEVELS IN THE NEONATAL RAT CEREBELLUM

The cerebellum is especially vulnerable to ethanol's neurotoxic effect s during development, and ethanol exposure during the brain growth spu rt will deplete cerebellar neurons. The mechanisms underlying this neu ronal cell loss remain elusive. Nerve growth factor (NGF) is a neurotr ophin that promotes cell survival in various brain areas, and there is evidence that NGF may play a role in the developing cerebellum, This study examined whether ethanol exposure of the neonatal rat cerebellum altered the levels of either NGF or the expression of p75 and trkA, w hich are two components of the NGF receptor. Ethanol exposure had no e ffect on NGF levels in the neonatal cerebellum, as determined by an NG F-specific ELISA. Immunohistochemical labeling techniques indicated th at both the p75 and trkA NGF receptors were expressed on Purkinje cell dendrites in the developing cerebellum, with posterior lobules expres sing higher levels of p75 and trkA NGF receptor, compared with anterio r lobules. Ethanol exposure of neonatal rats reduced the expression of both p75 and trkA NGF receptors on the Purkinje cell dendrites. These results suggest that ethanol could interfere with neurotrophic suppor t of Purkinje cells by reducing the levels of available NGF receptor.