The neurotransmitter dopamine, which is involved in drug addiction and certain psychiatric disorders, binds to five subtypes of receptor in the brain. Some psychiatric drugs block two of these receptors, the similar D2R and D3R, but often have side effects. Researchers have now elucidated the crystal structure of D3R, which is a potential target for new drugs to treat substance abuse. The structure may help drug developers to tailor their compounds to this and related receptors.
Raymond Stevens at the Scripps Research Institute in La Jolla, California, and his colleagues crystallized D3R in complex with a drug, eticlopride, that binds both D3R and D2R. On comparing the structure with that of a molecule that blocks only D3R, they found that D3R has a second binding site not present on D2R.