FOS AND JUN AS MARKERS FOR ETHANOL-SENSITIVE PATHWAYS IN THE RAT-BRAIN

The expression of proteins coded by the immediate early genes of the f os family and c-jun was used to study the effect of acute ethanol admi nistration on convulsant-induced neuronal activity in mt brain. Immuno reactivity for both types of protein was induced by either SC injectio n of pentylenetetrazole or by IP injection of N-methyl-D-aspartic acid . Both agents elicited distinct patterns of behaviour and a high level of FOS-immunoreactivity in the cerebral cortex and hippocampus. Acute IP doses of ethanol (1.0-3.0 g/kg) significantly reduced the behaviou rs and FOS-immunoreactivity induced in the cerebral cortex by both pen tylenetetrazole and N-methyl-D-aspartic acid. Pentylenetetrazole-induc ed FOS-immunoreactivity in the hippocampus was also inhibited by ethan ol. In contrast, N-methyl-D-aspartic acid-induced FOS-immunoreactivity in the hippocampus was not inhibited by any dose of ethanol. c-JUN im munoreactivity showed a distinct pattern of induction in the hippocamp us after injection of N-methyl-D-aspartic acid. Ethanol (3.0 g/kg) inh ibited N-methyl-D-aspartic acid-induced c-JUN-immunoreactivity in the hippocampus and cerebral cortex. The differences in inhibition of immu noreactivity suggest that the sensitivity of the NMDA- and GABA(A)-rel ated neuronal pathways to ethanol varies among different anatomical st ructures.