Previous microarray studies showed strong GABAB1 expression in human alcoholic prefrontal cortices (5, 6). However, these microarray experiments used cDNA probes, and two out of three GABAB1 probes were complimentary to regions apparently generated by unknown splicings. For example, clone 300899 was aligned to GABAB1 intron 4. It is a common intron region from the RefSeq Genes model and major GABAB1 splicing variant (7). Five different splicing variants were cloned containing clone 300899 (7, 8) including GABAB1m spliced out at exon 6 (7). Another probe, clone 2312175, targeted an unknown splicing-out at exon 23. Thus, the microarray experiments and splice variants suggested complex GABAB1 gene splicing in human brain (7-10).
