title: GABA-A and NMDA receptor subunit mRNA expression is altered in the caudate but not the putamen of the postmortem brains of alcoholics.
abstract: Chronic consumption of alcohol by humans has been shown to lead to impairment of executive and cognitive functions. Here, we have studied the mRNA expression of ion channel receptors for glutamate and GABA in the dorsal striatum of post-mortem brains from alcoholics (n = 29) and normal controls (n = 29), with the focus on the caudate nucleus that is associated with the frontal cortex executive functions and automatic thinking and on the putamen area that is linked to motor cortices and automatic movements. The results obtained by qPCR assay revealed significant changes in the expression of specific excitatory ionotropic glutamate and inhibitory GABA-A receptor subunit genes in the caudate but not the putamen. Thus, in the caudate we found reduced levels of mRNAs encoding the GluN2A glutamate receptor and the δ, ε, and ρ2 GABA-A receptor subunits, and increased levels of the mRNAs encoding GluD1, GluD2, and GABA-A γ1 subunits in the alcoholics as compared to controls. Interestingly in the controls, 11 glutamate and 5 GABA-A receptor genes were more prominently expressed in the caudate than the putamen (fold-increase varied from 1.24 to 2.91). Differences in gene expression patterns between the striatal regions may underlie differences in associated behavioral outputs. Our results suggest an altered balance between caudate-mediated voluntarily controlled and automatic behaviors in alcoholics, including diminished executive control on goal-directed alcohol-seeking behavior.
authors.affiliation: Molecular Physiology and Neuroscience, Biomedical Center, Uppsala University Uppsala, Sweden.
authors.forename: Amol K
authors.initials: AK
authors.lastname: Bhandage
authors.affiliation: Molecular Physiology and Neuroscience, Biomedical Center, Uppsala University Uppsala, Sweden.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Jin
authors.affiliation: Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland.
authors.forename: Igor
authors.initials: I
authors.lastname: Bazov
authors.affiliation: Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland.
authors.forename: Olga
authors.initials: O
authors.lastname: Kononenko
authors.affiliation: Pharmacology, Institute of Biomedicine, University of Helsinki Helsinki, Finland.
authors.forename: Georgy
authors.initials: G
authors.lastname: Bakalkin
authors.affiliation: Department of Pharmaceutical Bioscience (Biological Research on Drug Dependence), Biomedical Center, Uppsala University Uppsala, Sweden.
authors.forename: Esa R
authors.initials: ER
authors.lastname: Korpi
authors.affiliation: Molecular Physiology and Neuroscience, Biomedical Center, Uppsala University Uppsala, Sweden.
authors.forename: Bryndis
authors.initials: B
authors.lastname: Birnir
keywords: AMPA; GABA; alcoholism; excitation; glutamate receptor; inhibition; kainate