Should we be cautious on the use of commercially available antibodies to dopamine receptors?

Evidence indicate that it is difficult to obtain specific antibodies to G protein-coupled receptors and different technical difficulties may allow the generation of antibodies that lack specificity. We conducted experiments to validate the specificity of commercially available antibodies raised against dopamine (DA) receptors hD₁, hD₄, and hD₅ using a transfection approach: we studied whether, in HEK 293 cells selectively transfected with the various cloned subtypes, each antibody generates bands only in cells expressing its cognate receptor but not in those expressing the other DA receptors. Our results demonstrated that hD₁ and hD₄ receptor antibodies recognize not only their respective epitope, but also other DA receptor subtypes, while for the hD₅ receptor detection, we observed a signal only in the lane loaded with hD₅-transfected HEK 293 cells, although with a lack of purity. Therefore, we recommend caution on the use of commercially available DA receptor antibodies.