Laminar patterns of expression of GABAA receptor subunit mRNAs in monkey sensory motor cortex

Publisher Website
Google Scholar
Abstract
Radioactive complementary RNA probes, made from monkey-specific cDNAs specific for the α1, α2, α4, α5, β1, β2, and γ2 and γ2 subunits of the γ-aminobutyric acid A (GABAA) receptor were used for in situ hybridization histochemistry of the primary motor, somatosensory, and anterior parietal areas of thecerebral cortex in macaque monkeys. mRNAs for the α1, β2, and α2, subunit polypeptides, which form receptors with the full range of classical properties, are expressed at much higher levels in all areas and show laminar and sublaminar-specific concentrations. α2, α4, α5, and β1 subunit transcripts are expressed at much lower levels but also display individual, laminar-specific concentrations; α5, expression, in particular, is highly expressed in layer IV in the somatosensory and parietal areas and in a layer IV-like band in the motor cortex. In layers in which expression of a particular transcript is high, all neurons may express the gene, but in layers in which expression is moderate, it is possible to detect differences in the degree of labeling of individual neurons for a particular mRNA, and some neurons may not express certain subunit transcripts in detectable amounts. These findings indicate the variability in expression of different GABAA receptor subunits in the cerebral cortex. Laminar differences may indicate the assembly of functional receptors from different arrangements of available subunits in different classes of cells. © 1995 Wiley-Liss Inc.