Human D3 receptor is a 400 aa, G-protein coupled, and transmembrane receptor protein (1-2). A 19aa Peptide (Control peptide) sequence from the human D3 receptor within the 3rd cytoplasmic domain. The 19 AA human D3R peptide showed no significant sequence homology with other dopamine receptors (D1, D2, D4 or D5). It has sequence homology of 94% with monkey (18/19 AA) and 73% with mouse/rat (14/19 AA) D3R receptors.