Localization of α2A- and α2B-Adrenergic Receptor Subtypes in Brain

Abstract

Abstract Recent studies have shown that all three subtypes of α 2 -adrenergic receptor (α 2 -AR) are found in brain. The purpose of this study was to map the subtype localization of the α 2A - and α 2B -ARs in brain structures. RNase protection shows that both the α 2A - and α 2B -ARs are detectable in cortex, cerebellum, pons-medulla, and hypothalamus. We tested probes derived from the α 2A - and α 2B -AR cDNAs on cell lines that express each of the α 2 -AR subtypes to establish the subtype specificity of these probes for in situ hybridization. Then we used the α 2A - and α 2B -AR probes for in situ hybridization on sagittal and coronal sections of rat brain. Both α 2A and α 2B mRNA were detected throughout the brain. Overall, there appears to be a greater expression of message for α 2A - than α 2B -AR in most brain areas, with the exception of the thalamus. Developing these probes for in situ hybridization is an important step for further studies on the exact role of the α 2 -AR subtypes in neurons that modulate cardiovascular function.