Dopamine is a neurotransmitter that occurs in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors—D1, D2, D3, D4, and D5—and their variants. Dopamine is produced in several areas of the brain, including the substantia nigra and the ventral tegmental area. Dopamine is also a neurohormone released by the hypothalamus. Its main function as a hormone is to inhibit the release of prolactin from the anterior lobe of the pituitary.
Neurotransmitters with discrete localization within the
brain. A) The chemical structure of the monoamine neurotransmitter dopamine and a schematic drawing of the localization of dopamine-containing neurons in the human and rat
brain and the sites where dopamine-containing axons are found. B) The chemical structure of the monoamine neurotransmitter
serotonin and similar
brain map showing locations of
serotonin-containing cells and their axons.
Dopamine can be supplied as a medication that acts on the sympathetic nervous system, producing effects such as increased heart rate and blood pressure. However, because dopamine cannot cross the blood-brain barrier, dopamine given as a drug does not directly affect the central nervous system. To increase the amount of dopamine in the brains of patients with diseases such as Parkinson's disease and dopa-responsive dystonia, L-DOPA, which is the precursor of dopamine, can be given because it can cross the blood-brain barrier.
The function of dopamine as a neurotransmitter was discovered in 1958 by Arvid Carlsson and Nils-Åke Hillarp at the Laboratory for Chemical Pharmacology of the National Heart Institute of Sweden. It was named dopamine because it was a monoamine, and its synthetic precursor was 3,4-''d''ihydr''o''xy''p''henyl''a''lanine (L-DOPA). Arvid Carlsson was awarded the 2000 Nobel Prize in Physiology or Medicine for showing that dopamine is not just a precursor of norepinephrine (noradrenaline) and epinephrine (adrenaline) but a neurotransmitter, as well.
Dopamine was first synthesized in 1910 by George Barger and James Ewens at Wellcome Laboratories in London, England.
Further Reading
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Dopamine" All material adapted used from Wikipedia is available under the terms of the GNU Free Documentation License. Wikipedia® itself is a registered trademark of the Wikimedia Foundation, Inc.
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