Localization of the Dopamine D 1 Receptor Protein in the Human Heart and Kidney

Abstract
The dopamine D1 receptor has recently been identified in the rat heart and kidney. In the present study, using Western blot analysis and light microscopic immunohistochemistry, we examined D1 receptor protein expression in the human kidney and heart. Antipeptide polyclonal rabbit antiserum was raised against the third extracellular domain of the native receptor and affinity-purified using a protein-A column. Selectivity of the antiserum was validated by recognition of the D1 receptor expressed in stably transfected LTK− cells and Sf-9 cells. The immunohistochemical staining for D1 receptor protein was distributed throughout the atrium and ventricular myocardium and in the coronary vessels. In the kidney, positive immunoreactive signal was detected in the proximal and distal tubules, the collecting ducts, and the large intrarenal vasculature, whereas staining was absent in the juxtaglomerular (JG) cells and the glomeruli. D1 receptor antiserum preadsorbed against the immunizing peptide did not pro...