Differential α 2A - and α 2C -adrenoceptor protein expression in presynaptic and postsynaptic density fractions of postmortem human prefrontal cortex

Background:Three different α2-adrenoceptor (α2-AR) subtypes have been described. The α2A-AR and α2C-AR subtypes are highly expressed in the human prefrontal cortex, where they modulate neurotransmission. However, due to the lack of subtype-selective ligands, the physiological relevance of both subtypes has not been fully resolved.Aims:In this context, the aim of the present study was to characterize the protein expression of both α2-AR subtypes, in different synaptic fractions of postmortem human prefrontal cortex.Methods:A subcellular fractionation of the samples was performed and the protein expression of α2A- and α2C-ARs was measured in presynaptic membranes and postsynaptic density fractions by Western blot.Results:The results revealed that the α2A-AR subtype is mainly located postsynaptically (95±3%) whereas the remaining 5±3% is in the presynapse. Conversely, the α2C-AR subtype showed a similar distribution between pre- and postsynaptic membranes, with a slightly higher percentage present in the pre...