Rasgrf2 controls dopaminergic adaptations to alcohol in mice

Abstract

Alcohol abuse leads to serious health problems with no effective treatment available. Recent evidence suggests a role for ras-specific guanine-nucleotide releasing factor 2 (RASGRF2) in alcoholism. Rasgrf2 is a calcium sensor and MAPK/ERK activating protein, which has been linked to neurotransmitter release and monoaminergic receptor adaptations. Rasgrf2 knock out (KO) mice do not develop a dopamine response in the nucleus accumbens after an alcohol challenge and show a reduced consumption of alcohol. The present study aims to further characterise the role of Rasgrf2 in dopaminergic activation beyond the nucleus accumbens following alcohol treatment. Using in vivo microdialysis we found that alcohol induces alterations in dopamine levels in the dorsal striatum between wildtype (WT) and Rasgrf2 KO mice. There was no difference in the expression of dopamine transporter (DAT), dopamine receptor regulating factor (DRRF), or dopamine D2 receptor (DRD2) mRNA in the brain between Rasgrf2 KO and WT mice. After sub-chronic alcohol treatment, DAT and DRRF, but not DRD2 mRNA expression differed between WT and Rasgrf2 KO mice. Brain adaptations were positively correlated with splenic expression levels. These data suggest that Rasgrf2 controls dopaminergic signalling and adaptations to alcohol also in other brain regions, beyond the nucleus accumbens.

Keywords: Alcohol; Dopamine; Gene expression; Microdialysis; Rasgrf2; Striatum.