Catalase-independent early-gene expression in rat brain following acute ethanol exposure.

Early-gene expression evoked by acute ethanol treatment was studied in rat brain by quantitative immunocytochemistry, with reference to ethanol metabolism by the enzyme catalase. Colocalization with mu-opioid receptor (MOR) sites was also examined. Ethanol challenges [1, 2.5, and 4 g/kg intraperitoneally (i.p.)] evoked dose-dependent increases in c-Fos expression in several brain regions, but overlap with MOR-rich sites was only partial. Strong inhibition of brain catalase activity (ca. 60%) with 3-amino-1,2,4-triazole (AT, 1 g/kg i.p.) did not alter ethanol-induced c-Fos nor Krox-24 expression in any of the brain regions analyzed. This evidence demonstrates that catalase-mediated metabolism is not a requisite for c-Fos nor Krox-24 induction in rat brain following acute ethanol treatment, and suggests that ethanol is by itself capable of eliciting strong neuronal and circuit-level adaptations in the nervous system.