Nucleus-specific expression of GABAA receptor subunit mRNAs in monkey thalamus.

Expression of 10 GABAA receptor subunit genes was examined in monkey thalamus by in situ hybridization using cRNA probes specific for α1, α2, α3, α4, α5, β1, β2, β3, γ1, and γ2 subunit mRNAs. These displayed unique hybridization patterns with significant differences from rodents, α1, β2, and γ2 transcripts were expressed at high levels in all dorsal thalamic nuclei, but expression was significantly higher in sensory relay nuclei - especially the dorsal lateral geniculate nucleus. Other transcripts showed nucleus-specific differences in levels of expression and in the range expressed. α5 and α4 subunit transcripts were expressed in all nuclei except the intralaminar nuclei. Levels of α2, α3, β1, β3, and γ1 expression were very low, except in intralaminar nuclei. In the reticular nucleus, most subunit transcripts were not expressed, and only γ2 transcripts were consistently detected at modest levels. Thalamic GABAA receptors may be assembled from nucleus-specific groupings of subunit polypeptides.