Expression of GABA(B1) and GABA(B2) mRNA in the human brain

GABA(B) receptors are widely expressed in the CNS. The distribution of the recently cloned GABA(B1) receptor is highly concordant with GABA(B) ligand binding sites, but experiments with transfected cell lines indicate that GA BA(B1) has to heterodimerize with GABA(B2) to gain the functionality of a n ative GABA(B) receptor. Using in situ hybridization we investigated the exp ression of GABA(B1) and GABAB2 mRNAs in the human brain. Both transcripts w ere detectable in prefrontal-cortex, hippocampus and cerebellum with no app arent mismatch. A distinct expression of GABA(B1) was detected in putative Bergmann glia. In the human striatum GABA(B1) mRNA was expressed in moderat e amounts, whereas the GABAB2 mRNA signal was not clearly above background. According to our data, the current concept on GABA(B) receptor composition needs re-evaluation, at least for certain brain structures. NeuroReport 12 :3269-3275 (C) 2001 Lippincott Williams & Wilkins.