Dopamine receptor D₂, also known as D2R, is a protein that, in humans, is encoded by the DRD2 gene.The dopamine D₂ receptor was discovered in 1975 by Philip Seeman who had named it as the antipsychotic dopamine receptor The dopamine D₂ receptor is the main receptor for all antipsychotic drugs. Any drug that does not interfere with dopamine action at the D₂ receptor does not have an antipsychotic action.