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<p><font color="#000000"><strong>Dopamine</strong> is a catecholamine neurotransmitter present 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&mdash;D_{<font size="2">1</font>}, D_{<font size="2">2</font>}, D_{<font size="2">3</font>}, D_{<font size="2">4</font>}, and D_{<font size="2">5</font>}&mdash;and their variants. Dopamine is produced in several areas of the brain, including the substantia nigra and the ventral tegmental area.<sup id="cite_ref-0" class="reference"><font size="2"><span>[</span>1<span>]</span></font></sup> 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.</font></p>

<p><font color="#000000">Dopamine is available as an intravenous medication acting 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.</font></p>

<h2><span id="History" class="mw-headline"><font color="#000000">History</font></span></h2>

<p><font color="#000000">Dopamine was first synthesized in 1910 by George Barger and James Ewens at Wellcome Laboratories in London, England.<sup id="cite_ref-1" class="reference"><font size="2"><span>[</span>2<span>]</span></font></sup> It was named dopamine because it was a monoamine, and its synthetic precursor was 3,4-<em>d</em>ihydr<em>o</em>xy<em>p</em>henyl<em>a</em>lanine (L-DOPA). Dopamine's function as a neurotransmitter was first recognized in 1958 by Arvid Carlsson and Nils-&Aring;ke Hillarp at the Laboratory for Chemical Pharmacology of the National Heart Institute of Sweden.<sup id="cite_ref-2" class="reference"><font size="2"><span>[</span>3<span>]</span></font></sup> 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.</font></p>