NICOTINE INCREASES DIAZEPAM-BINDING INHIBITOR (DBI) MESSENGER-RNA IN PRIMARY CULTURED NEURONS

The effect of nicotine on the expression of diazepam binding inhibitor (DBI) mRNA in primary cultured cerebral cortical neurons was examined using Northern blot analysis. Nicotine exposure (0.001-10 mu M) for 24 h increased the DBI mRNA level in a dose-dependent manner, whereas the p-actin mRNA level showed no change. This effect of nicotine was faded out over 48 h of its exposure. Hexamethonium (100 mu M) completely abolished the nicotine-induced increase in DBI mRNA expression. These results indicate that nicotine increases the expression of DBI mRNA in cerebral cortical neurons via the activation of nicotinic acetylcholine receptor.