dopamine is mainly a neurotransmitter: a small molecule that one nerve releases when stimulated in order to stimulate other nearby nerves. dopamine acts in many vital circuits inside the brain and is involved in thinking learning movement motivation and pleasure and other domains. drugs like cocaine and methamphetamine act on dopamine-releasing nerves in the brain to help produce their high. medicines to treat schizophrenia and parkinson’s disease act on other dopamine-releasing nerves with very different effects. dopamine is also sometimes used as a medicine in people who are critically ill with dangerously low blood pressure (shock). given in high doses intravenously dopamine causes the heart to beat harder and blood vessels to constrict raising blood pressure.
what is dopamine?