Differential expression of GABAA receptor subunits in the distinct nuclei of the rat amygdala

Detailed knowledge of the anatomical distribution of different GABAA receptor subunits is crucial for understanding the physiological actions of GABA in individual brain areas and for developing drugs acting through the individual GABA receptor subtypes. Since the amygdala is a key brain structure in the processing of emotional information with distinct functions in each nucleus, GABAA receptors in the amygdala are an important target of treatment for emotional disorders. In this study, we analyzed by quantitative RT-PCR the expression levels of all GABAA receptor subunits in distinct nuclei of the amygdala, the central (Ce) and the lateral/basolateral (LA/BLA) amygdala. We found the strongest expression of the γ2 subunit mRNA in both the Ce and LA/BLA, modest expressions of α1, α2 and α3 mRNAs in the LA/BLA and α2 and γ1 mRNAs in the Ce, and weak expressions of α6, ρ2 and ρ3 mRNAs in both regions. We further revealed the significantly different expressions of α1, α3, α5, γ1, γ2, δ, ε and θ subunit mRNAs in the Ce and LA/BLA. Differences in the expression levels of GABAA receptor subunits suggest different sensitivity to a variety of drugs including benzodiazepines and anesthetics in amygdala nuclei with distinct functions.