Molecular cloning studies on five types of dopaniine receptors were summarized. The five types of dopamine receptors are members of family of the G protein-coupled receptors,and divided into two classes by pharmacologic and biochemical criteria (a) D₁R and D₅R mediating the activation of adenylyl cyclase through G protein (G_s) and (b) D₂R, D₃R, D₄R, inhibiting the activation of adenylyl cyclase through the G protein (G_i) . The gene structure, distribution of their mRNA in the brain and location on chroniosomes between the two classes of dopamine receptors were compared.