Dopamine << DOH puh meen >> is a chemical that acts in the brain to influence a wide range of feelings and behaviors, including paying attention, planning, and moving the body. Dopamine also plays a key role in motivation, pleasure, and addiction. Dopamine is one of a group of chemicals called neurotransmitters, which carry information from one neuron (nerve cell) to another.
The brain has a network of nerve cells that produce dopamine or respond to it. Deep inside the brain are two small clusters of dopamine-producing cells. These cells contain a chemical pathway that changes an amino acid called tyrosine first into a chemical called L-dopa and then into dopamine. Nerve cells that respond to dopamine have structures called dopamine receptors on their surface. There are five types of dopamine receptors. The effects of dopamine depend on where it is released, how much is released, and which types of receptors are activated. Brain levels of dopamine are highest in infancy, then decrease throughout life.
Many physical and mental disorders involve too much or too little dopamine. For example, all addicting drugs seem to raise dopamine levels in the same part of the brain. In people who develop addictions, these dopamine surges cause long-term, even permanent, changes in brain cells. Certain movement disorders, such as Parkinson disease, involve abnormal dopamine levels. Disruption of dopamine also plays a role in other conditions, including schizophrenia, attention deficit disorder, and Tourette syndrome.
