Dopamine

Dopamine is a chemical produced by the human body that acts as a neurotransmitter in the brain. Its chemical formula is (C₆H₃(OH)₂-CH₂-CH₂-NH₂) and its chemical name is 4-(2-aminoethyl)benzene-1,2-diol. Dopamine is abbreviated as DA. The brain contains five types of receptors to which dopamine binds (D1, D2, D3, D4 and D5).

Reward

Dopamine plays an important role in brain reward systems. Actions and substances that increase the amount of DA that is released in the brain are reinforcing; that is, they result in pleasurable feelings, motivating people to repeat the behavior. Dopamine is released by natural behaviors such as eating and sexual activity, and also by drugs such as cocaine and amphetamine.

Link to Mental Illness

Dopamine has also been linked to mental illness, particularly schizophrenia, which is characterized by psychotic episodes. Studies have shown that drugs which block D2 receptors (preventing dopamine from binding to them) reduce psychotic symptoms, and drugs which increase dopamine relase (e.g., cocaine) can lead to psychotic episodes. Most medications used in psychiatry to treat schizophrenia and other psychotic disorders work by inhibiting dopaminergic activity.

Therapeutic Uses

Dopamine is used to increase cardiac output and blood pressure. Levodopa (or L-DOPA), which is a dopamine precursor, is often used to treat Parkinsons' disease.