Modulation of c-fos expression in the rat striatum by diazepam.

The benzodiazepine agonist, diazepam, inhibits cAMP production in the rat brain. Since cAMP influences c-fos activity, we examined the effects of diazepam on expression of this immediate early gene, as indicated by Western blot analysis. Intraperitoneal administration of diazepam increased Fos protein levels in the striatum, but not in the hippocampus. In contrast, pretreatment with diazepam blocked the potent inducing effect of amphetamine, in both brain regions. Similar induction and blockade effects were also observed for a 90 kDa Fos related antigen (Fra), in the striatum and hippocampus. The possible mechanisms underlying the modulatory effects of diazepam on c-fos expression in the brain are discussed.