Genome-wide gene expression analysis identifies K-ras as a regulator of alcohol intake.

Adaptations in the anterior cingulate cortex (ACC) have been implicated in alcohol and drug addiction. To identify genes that may contribute to excessive drinking, here we performed microarray analyses in laser microdissected rat ACC after a single or repeated administration of an intoxicating dose of alcohol (3 g/kg). Expression of the small G protein K-ras was differentially regulated following both single and repeated alcohol administration.

Increased expression of protein kinase A inhibitor alpha (PKI-alpha) and decreased PKA-regulated genes in chronic intermittent alcohol exposure.

Intermittent models of alcohol exposure that mimic human patterns of alcohol consumption produce profound physiological and biochemical changes and induce rapid increases in alcohol self-administration. We used high-density oligonucleotide microarrays to investigate gene expression changes during chronic intermittent alcohol exposure in three brain regions that receive mesocorticolimbic dopaminergic projections and that are believed to be involved in alcohol's reinforcing actions: the medial prefrontal cortex, the nucleus accumbens and the amygdala. An independent replication of the experiment was used for RT-PCR validation of the microarray results.

Gene expression evidence for remodeling of lateral hypothalamic circuitry in cocaine addiction.

By using high-density oligonucleotide arrays, we profiled gene expression in reward-related brain regions of rats that developed escalated cocaine intake after extended access to cocaine (6 h per day). Rats allowed restricted daily access to cocaine (only 1 h) that displayed a stable level of cocaine intake and cocaine naive rats were used for controls. Four analysis methods were compared: Affymetrix microarray suite 4 and microarray suite 5, which use perfect-match-minus-mismatch models, and dchip and rma, which use perfect-match-only models to generate expression values.

Gene profiling of laser-microdissected brain regions and sub-regions.

The application of transcriptomics and proteomics approaches to accurately dissected anatomically-defined brain regions and sub-regions remains a central focus of current neurobiological investigations as well as a necessary step towards single-neuron neurogenomics and neuroproteomics. A protocol is described for the simple, rapid, and reproducible laser microdissection of brain regions and sub-regions for microarray-based gene expression analyses from individual rats or mice using two rounds of in vitro transcription (IVT). The results presented also demonstrate that the current Affymetrix GeneChip arrays are well suited for this experimental design with high reproducibility and limited effects of the shortening of target RNA caused by the double IVT approach.