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<p><strong>Dopamine</strong> is a <a title="Catecholamine" href="/wiki/Catecholamine"><font color="#0645ad000000">catecholamine</fontstrong>Dopamine</astrong> <is a title="Neurotransmitter" href="/wiki/Neurotransmitter"><font color="#0645ad">neurotransmitter</font></a> catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the <a title="Human brain" href="/wiki/Human_brain", this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors&mdash;D<sub><font colorsize="#0645ad2">brain1</font></asub>, this D<a titlesub><font size="Phenethylamine" href=2">2</wikifont></Phenethylamine"sub>, D<sub><font colorsize="#0645ad2">phenethylamine3</font></asub> functions as a , D<a titlesub><font size="Neurotransmitter" href=2">4</wikifont></Neurotransmitter"sub>, and D_{<font colorsize="#0645ad2">neurotransmitter5</font></asub>, activating the five types &mdash;and their variants. Dopamine is produced in several areas of the brain, including the substantia nigra and the ventral tegmental area.<a titlesup id="Dopamine receptorcite_ref-0" hrefclass="/wiki/Dopamine_receptorreference"><font colorsize="#0645ad2">dopamine receptors<span>[</span>1<span>]</span></font></asup>&mdash;<a class="mw-redirect" title="Dopamine D1 receptor" href="/wiki/Dopamine_D1_receptor"><font color="#0645ad"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>D<subp><font sizecolor="2#000000">1</font>}</font></a>Dopamine is available as an intravenous medication acting on the sympathetic nervous system, <a class="mwproducing effects such as increased heart rate and blood pressure. However, because dopamine cannot cross the blood-redirect" title="Dopamine D2 receptor" href="/wiki/Dopamine_D2_receptor"><font color="#0645ad">D_{<font size="2">2</font>}<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></ap>,  <a classh2><span id="mw-redirectHistory" titleclass="Dopamine D3 receptor" href="/wiki/Dopamine_D3_receptormw-headline"><font color="#0645ad000000">D<sub>History</font size="2">3</fontspan></subh2></font></a>, <a class="mw-redirect" title="Dopamine D4 receptor" href="/wiki/Dopamine_D4_receptor"p><font color="#0645ad000000">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">D<sub><font size="2">4</fontspan>[</subspan>2<span>]</span></font></sup> It was named dopamine because it was a>monoamine, and its synthetic precursor was 3,4-<em>d<a class="mw-redirect" title="Dopamine D5 receptor" href="/wiki/Dopamine_D5_receptor"em>ihydr<font color="#0645ad"em>Do<sub/em>xy<font size="2">5em>p</fontem>henyl</subem>a</fontem></a>&mdash;and their variantslanine (L-DOPA). Dopamine is produced 's function as a neurotransmitter was first recognized in several areas 1958 by Arvid Carlsson and Nils-&Aring;ke Hillarp at the Laboratory for Chemical Pharmacology of the brain, including the National Heart Institute of Sweden.<a titlesup id="Substantia nigracite_ref-2" hrefclass="/wiki/Substantia_nigrareference"><font colorsize="#0645ad2">substantia nigra</fontspan>[</aspan> and the 3<a title="Ventral tegmental area" href="/wiki/Ventral_tegmental_area"span>]<font color="#0645ad"/span>ventral tegmental area</font></asup>.<sup id="cite_ref-0" class="reference"><Carlsson was awarded the 2000 Nobel Prize in Physiology or Medicine for showing that dopamine is not just a href="#cite_note-0">precursor of norepinephrine (noradrenaline) and epinephrine (adrenaline), but a neurotransmitter as well.</font size="2"><font color="#0645ad"/p><spanh2>[</span>1<span>]</span></font></font></a></sup> Dopamine is also a <a title="Neurohormone" href="/wiki/Neurohormone"><font color="#0645ad">neurohormone</font></a> released by the <a title="Hypothalamus" href="/wiki/Hypothalamus"><font color="#0645ad">hypothalamus</font></a>. Its main function as a hormone is to inhibit the release of <a title="Prolactin" href="/wiki/Prolactin"><font color="#0645ad">prolactin</font></a> from the anterior lobe of the <a class="mw-redirect" title="Pituitary" href="/wiki/Pituitary"><font color="#0645ad">pituitary</font></a>.</p><p>Dopamine is available as an intravenous <a class="mw-redirect" title="Medication" href="/wiki/Medication"><font color="#0645ad">medication</font></a> acting on the <a title="Sympathetic nervous system" href="/wiki/Sympathetic_nervous_system"><font color="#0645ad">sympathetic</font></a> <a title="Nervous system" href="/wiki/Nervous_system"><font color="#0645ad">nervous system</font></a>, producing effects such as increased <a title="Heart rate" href="/wiki/Heart_rate"><font color="#0645ad">heart rate</font></a> and <a title="Blood pressure" href="/wiki/Blood_pressure"><font color="#0645ad">blood pressure</font></a>. However, because dopamine cannot cross the <a title="Blood-brain barrier" href="/wiki/Blood-brain_barrier"><font color="#0645ad">blood-brain barrier</font></a>, dopamine given as a drug does not directly affect the <a title="Central nervous system" href="/wiki/Central_nervous_system"><font color="#0645ad">central nervous system</font></a>. To increase the amount of dopamine in the brains of patients with diseases such as <a title="Parkinson's disease" href="/wiki/Parkinson%27s_disease"><font color="#0645ad">Parkinson's disease</font></a> and dopa-responsive <a title="Dystonia" href="/wiki/Dystonia"><font color="#0645ad">dystonia</font></a>, <a title="L-DOPA" href="/wiki/L-DOPA"><font color="#0645ad">L-DOPA</font></a>, which is the precursor of dopamine, can be given because it can cross the <a title="Blood-brain barrier" href="/wiki/Blood-brain_barrier"><font color="#0645ad">blood-brain barrier</font></a>.</p><p><table id="toc" class="toc"> <tbody> <tr> <td> <div id="toctitle"> <h2>Contents</h2> <span class="toctoggle"><font size="2">[</font><a id="togglelink" class="internal" href="#"><font color="#0645ad" size="2">hide</font></a><font size="2">]</font></span></div> <ul> <li class="toclevel-1 tocsection-1"><a href="#History"><font color="#0645ad"><span class="tocnumber">1</span> <span class="toctext">History</span></font></a></li> <li class="toclevel-1 tocsection-2"><a href="#Biochemistry"><font color="#0645ad"><span class="tocnumber">2</span> <span class="toctext">Biochemistry</span></font></a> <ul> <li class="toclevel-2 tocsection-3"><a href="#Name_and_family"><font color="#0645ad"><span class="tocnumber">2.1</span> <span class="toctext">Name and family</span></font></a></li> <li class="toclevel-2 tocsection-4"><a href="#Biosynthesis"><font color="#0645ad"><span class="tocnumber">2.2</span> <span class="toctext">Biosynthesis</span></font></a></li> <li class="toclevel-2 tocsection-5"><a href="#Inactivation_and_degradation"><font color="#0645ad"><span class="tocnumber">2.3</span> <span class="toctext">Inactivation and degradation</span></font></a></li> </ul> </li> <li class="toclevel-1 tocsection-6"><a href="#Functions_in_the_brain"><font color="#0645ad"><span class="tocnumber">3</span> <span class="toctext">Functions in the brain</span></font></a> <ul> <li class="toclevel-2 tocsection-7"><a href="#Anatomy"><font color="#0645ad"><span class="tocnumber">3.1</span> <span class="toctext">Anatomy</span></font></a></li> <li class="toclevel-2 tocsection-8"><a href="#Tonic_and_phasic_activity"><font color="#0645ad"><span class="tocnumber">3.2</span> <span class="toctext">Tonic and phasic activity</span></font></a></li> <li class="toclevel-2 tocsection-9"><a href="#Movement"><font color="#0645ad"><span class="tocnumber">3.3</span> <span class="toctext">Movement</span></font></a></li> <li class="toclevel-2 tocsection-10"><a href="#Cognition_and_frontal_cortex"><font color="#0645ad"><span class="tocnumber">3.4</span> <span class="toctext">Cognition and frontal cortex</span></font></a></li> <li class="toclevel-2 tocsection-11"><a href="#Regulating_prolactin_secretion"><font color="#0645ad"><span class="tocnumber">3.5</span> <span class="toctext">Regulating prolactin secretion</span></font></a></li> <li class="toclevel-2 tocsection-12"><a href="#Motivation_and_pleasure"><font color="#0645ad"><span class="tocnumber">3.6</span> <span class="toctext">Motivation and pleasure</span></font></a> <ul> <li class="toclevel-3 tocsection-13"><a href="#Reinforcement"><font color="#0645ad"><span class="tocnumber">3.6.1</span> <span class="toctext">Reinforcement</span></font></a></li> <li class="toclevel-3 tocsection-14"><a href="#Reuptake_inhibition.2C_expulsion"><font color="#0645ad"><span class="tocnumber">3.6.2</span> <span class="toctext">Reuptake inhibition, expulsion</span></font></a></li> <li class="toclevel-3 tocsection-15"><a href="#Incentive_salience"><font color="#0645ad"><span class="tocnumber">3.6.3</span> <span class="toctext">Incentive salience</span></font></a></li> <li class="toclevel-3 tocsection-16"><a href="#Dopamine.2C_learning.2C_and_reward-seeking_behavior"><font color="#0645ad"><span class="tocnumber">3.6.4</span> <span class="toctext">Dopamine, learning, and reward-seeking behavior</span></font></a></li> <li class="toclevel-3 tocsection-17"><a href="#Animal_studies"><font color="#0645ad"><span class="tocnumber">3.6.5</span> <span class="toctext">Animal studies</span></font></a></li> <li class="toclevel-3 tocsection-18"><a href="#The_effects_of_drugs_that_reduce_dopamine_activity"><font color="#0645ad"><span class="tocnumber">3.6.6</span> <span class="toctext">The effects of drugs that reduce dopamine activity</span></font></a></li> <li class="toclevel-3 tocsection-19"><a href="#Opioid_and_cannabinoid_transmission"><font color="#0645ad"><span class="tocnumber">3.6.7</span> <span class="toctext">Opioid and cannabinoid transmission</span></font></a></li> <li class="toclevel-3 tocsection-20"><a href="#Sociability"><font color="#0645ad"><span class="tocnumber">3.6.8</span> <span class="toctext">Sociability</span></font></a></li> <li class="toclevel-3 tocsection-21"><a href="#Processing_of_pain"><font color="#0645ad"><span class="tocnumber">3.6.9</span> <span class="toctext">Processing of pain</span></font></a></li> <li class="toclevel-3 tocsection-22"><a href="#Salience"><font color="#0645ad"><span class="tocnumber">3.6.10</span> <span class="toctext">Salience</span></font></a></li> <li class="toclevel-3 tocsection-23"><a href="#Behavior_disorders"><font color="#0645ad"><span class="tocnumber">3.6.11</span> <span class="toctext">Behavior disorders</span></font></a></li> </ul> </li> <li class="toclevel-2 tocsection-24"><a href="#Latent_inhibition_and_creative_drive"><font color="#0645ad"><span class="tocnumber">3.7</span> <span class="toctext">Latent inhibition and creative drive</span></font></a></li> <li class="toclevel-2 tocsection-25"><a href="#Chemoreceptor_trigger_zone"><font color="#0645ad"><span class="tocnumber">3.8</span> <span class="toctext">Chemoreceptor trigger zone</span></font></a></li> <li class="toclevel-2 tocsection-26"><a href="#Dopaminergic_mind_hypothesis"><font color="#0645ad"><span class="tocnumber">3.9</span> <span class="toctext">Dopaminergic mind hypothesis</span></font></a></li> </ul> </li> <li class="toclevel-1 tocsection-27"><a href="#Links_to_psychosis"><font color="#0645ad"><span class="tocnumber">4</span> <span class="toctext">Links to psychosis</span></font></a></li> <li class="toclevel-1 tocsection-28"><a href="#Therapeutic_use"><font color="#0645ad"><span class="tocnumber">5</span> <span class="toctext">Therapeutic use</span></font></a></li> <li class="toclevel-1 tocsection-29"><a href="#Nonneural_functions"><font color="#0645ad"><span class="tocnumber">6</span> <span class="toctext">Nonneural functions</span></font></a> <ul> <li class="toclevel-2 tocsection-30"><a href="#Immunoregulatory"><font color="#0645ad"><span class="tocnumber">6.1</span> <span class="toctext">Immunoregulatory</span></font></a></li> <li class="toclevel-2 tocsection-31"><a href="#Peripheral_effects"><font color="#0645ad"><span class="tocnumber">6.2</span> <span class="toctext">Peripheral effects</span></font></a></li> <li class="toclevel-2 tocsection-32"><a href="#Renal_effects"><font color="#0645ad"><span class="tocnumber">6.3</span> <span class="toctext">Renal effects</span></font></a></li> </ul> </li> <li class="toclevel-1 tocsection-33"><a href="#Dopamine_and_fruit_browning"><font color="#0645ad"><span class="tocnumber">7</span> <span class="toctext">Dopamine and fruit browning</span></font></a></li> <li class="toclevel-1 tocsection-34"><a href="#See_also"><font color="#0645ad"><span class="tocnumber">8</span> <span class="toctext">See also</span></font></a></li> <li class="toclevel-1 tocsection-35"><a href="#References"><font color="#0645ad"><span class="tocnumber">9</span> <span class="toctext">References</span></font></a></li> <li class="toclevel-1 tocsection-36"><a href="#External_links"><font color="#0645ad"><span class="tocnumber">10</span> <span class="toctext">External links</span></font></a></li> </ul> </td> </tr> </tbody></table><script type="text/javascript">//<![CDATA[if (window.showTocToggle) { var tocShowText = "show"; var tocHideText = "hide"; showTocToggle(); } //]]></script></p><h2><span class="editsection">[<a title="Edit section: History" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=1"><font color="#0645ad">edit</font></a>]</span> <span id="History" class="mw-headline">History</span></h2><p>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"><a href="#cite_note-1"><font size="2"><font color="#0645ad"><span>[</span>2<span>]</span></font></font></a></sup> It was named dopamine because it was a <a class="mw-redirect" title="Monoamine" href="/wiki/Monoamine"><font color="#0645ad">monoamine</font></a>, and its synthetic precursor was 3,4-<em>d</em>ihydr<em>o</em>xy<em>p</em>henyl<em>a</em>lanine (<a title="L-DOPA" href="/wiki/L-DOPA"><font color="#0645ad">L-DOPA</font></a>). Dopamine's function as a neurotransmitter was first recognized in 1958 by <a title="Arvid Carlsson" href="/wiki/Arvid_Carlsson"><font color="#0645ad">Arvid Carlsson</font></a> and Nils-&Aring;ke Hillarp at the Laboratory for Chemical Pharmacology of the National Heart Institute of <a title="Sweden" href="/wiki/Sweden"><font color="#0645ad">Sweden</font></a>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><font size="2"><font color="#0645ad"><span>[</span>3<span>]</span></font></font></a></sup> Carlsson was awarded the 2000 <a title="Nobel Prize in Physiology or Medicine" href="/wiki/Nobel_Prize_in_Physiology_or_Medicine"><font color="#0645ad">Nobel Prize in Physiology or Medicine</font></a> for showing that dopamine is not just a precursor of <a titleid="NorepinephrineBiochemistry" hrefclass="/wiki/Norepinephrine"><font color="#0645ad">norepinephrine</font></a> (noradrenaline) and <a title="Epinephrine" href="/wiki/Epinephrinemw-headline"><font color="#0645ad">epinephrine</font></a> (adrenaline), but a neurotransmitter as well.</p><h2><span class="editsection000000">[<a title="Edit section: Biochemistry" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=2"><font color="#0645ad">edit</font></a>]</span> <span id="Biochemistry" class="mw-headline">Biochemistry</span></h2>

<div style="WIDTH: 222px" class="thumbinner"><a classfont color="image" href="/wiki/File:Catecholamines_biosynthesis.svg#000000"><img class="thumbimage" alt="" width="220" height="500" src="http://upload.wikimedia.org/wikipedia/commons/thumb/0/08/Catecholamines_biosynthesis.svg/220px-Catecholamines_biosynthesis.svg.png" width="220" height="500" /></afont>

<div class="magnify"><a classfont color="internal#000000" title><img alt="Enlarge" hrefwidth="/wiki/File:Catecholamines_biosynthesis.svg15"><img altheight="11" src="http://bits.wikimedia.org/skins-1.5/common/images/magnify-clip.png" width="15" height="11" /></afont></div><font color="#000000">Biosynthesis of dopamine</font></div>

<h3><span classid="editsectionName_and_family">[<a titleclass="Edit section: Name and family" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=3mw-headline"><font color="#0645ad000000">editName and family</font></a>]</span> <span id="Name_and_family" class="mw-headline">Name and family</span></h3><p><font color="#000000">Dopamine has the chemical formula C_{<font size="2">6</font>}H_{<font size="2">3</font>}(OH)_{<font size="2">2</font>}-CH_{<font size="2">2</font>}-CH_{<font size="2">2</font>}-NH_{<font size="2">2</font>}. Its chemical name is &quot;4-(2-aminoethyl)benzene-1,2-diol&quot; and its abbreviation is &quot;DA.&quot;</font></p><p>As a member of the <a title="Catecholamine" href="/wiki/Catecholamine"><font color="#0645ad000000">As a member of the catecholamine</font></a> family, dopamine is a precursor to <a title="Norepinephrine" href="/wiki/Norepinephrine"><font color="#0645ad">norepinephrine</font></a> (noradrenaline) and then <a title="Epinephrine" href="/wiki/Epinephrine"><font color="#0645ad">epinephrine</font></a> (adrenaline) in the biosynthetic pathways for these neurotransmitters.</font></p><h3><span class="editsection">[<a titleid="Edit section: Biosynthesis" hrefclass="/w/index.php?title=Dopamine&amp;action=edit&amp;section=4mw-headline"><font color="#0645ad000000">editBiosynthesis</font></a>]</span> <span id="Biosynthesis" class="mw-headline">Biosynthesis</span></h3><p><font color="#000000">Dopamine is biosynthesized in the body (mainly by nervous tissue and the <a title="Adrenal medulla" href="/wiki/Adrenal_medulla"><font color="#0645ad">medulla</font></a> of the <a title="Adrenal gland" href="/wiki/Adrenal_gland"><font color="#0645ad">adrenal glands</font></a>) first by the hydroxylation of the amino acid <a class="mw-redirect" title="L-tyrosine" href="/wiki/L-tyrosine"><font color="#0645ad">L-tyrosine</font></a> to L-DOPA via the enzyme tyrosine 3-monooxygenase, also known as <a title="Tyrosine hydroxylase" href="/wiki/Tyrosine_hydroxylase"><font color="#0645ad">tyrosine hydroxylase</font></a>, and then by the <a title="Decarboxylation" href="/wiki/Decarboxylation"><font color="#0645ad">decarboxylation</font></a> of <a title="L-DOPA" href="/wiki/L-DOPA"><font color="#0645ad">L-DOPA</font></a> by <a title="Aromatic L-amino acid decarboxylase" href="/wiki/Aromatic_L-amino_acid_decarboxylase"><font color="#0645ad">aromatic L-amino acid decarboxylase</font></a> (which is often referred to as dopa decarboxylase). In some neurons, dopamine is further processed into <a title="Norepinephrine" href="/wiki/Norepinephrine"><font color="#0645ad">norepinephrine</font></a> by <a class="mw-redirect" title="Dopamine beta-hydroxylase" href="/wiki/Dopamine_beta-hydroxylase"><font color="#0645ad">dopamine beta-hydroxylase.</font></a>.</p><p>In <a title="Neuron" href="/wiki/Neuron"><font color="#0645ad000000">In neurons</font></a>, dopamine is packaged after synthesis into <a class="mw-redirect" title="Vesicle (biology)" href="/wiki/Vesicle_(biology)"><font color="#0645ad">vesicles</font></a>, which are then released into the <a title="Synapse" href="/wiki/Synapse"><font color="#0645ad">synapse</font></a> in response to a presynaptic <a title="Action potential" href="/wiki/Action_potential"><font color="#0645ad">action potential.</font></a>.</p><div style="CLEAR: both"><font color="#000000"></font></div>

<div style="WIDTH: 222px" class="thumbinner"><a classfont color="image" href="/wiki/File:Dopamine_degradation.svg#000000"><img class="thumbimage" alt="" width="220" height="211" src="http://upload.wikimedia.org/wikipedia/commons/thumb/e/e7/Dopamine_degradation.svg/220px-Dopamine_degradation.svg.png" width="220" height="211" /></afont>

<div class="magnify"><a classfont color="internal#000000" title><img alt="Enlarge" hrefwidth="/wiki/File:Dopamine_degradation.svg15"><img altheight="11" src="http://bits.wikimedia.org/skins-1.5/common/images/magnify-clip.png" width="15" height="11" /></afont></div><font color="#000000">Biodegradation of dopamine</font></div>

<h3><span classid="editsectionInactivation_and_degradation">[<a titleclass="Edit section: Inactivation and degradation" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=5mw-headline"><font color="#0645ad000000">edit<Inactivation and degradation</font></aspan>]</spanh3><p> <span idfont color="Inactivation_and_degradation" class="mw-headline#000000">Inactivation and degradation</span></h3><p>Two major Two major degradation pathways for dopamine exist. In most areas of the brain, including the <a title="Striatum" href="/wiki/Striatum"><font color="#0645ad">striatum</font></a> striatum and basal ganglia, dopamine is inactivated by reuptake via the dopamine transporter (DAT1), then enzymatic breakdown by monoamine oxidase (MAOA and <a title="Basal ganglia" href="/wiki/Basal_ganglia"><font color="#0645ad">basal ganglia</font></a>MAOB) into 3,4-dihydroxyphenylacetic acid. In the prefrontal cortex, however, there are very few dopamine transporter proteins, and dopamine is instead inactivated by reuptake via the norepinephrine transporter (NET), presumably on neighboring norepinephrine neurons, then enzymatic breakdown by catechol-<a title="Reuptake" href="/wiki/Reuptake"><font color="#0645ad"em>reuptakeO</fontem>-methyl transferase (COMT) into 3-methoxytyramine.</a> via the <a titlesup id="Dopamine transportercite_ref-3" hrefclass="/wiki/Dopamine_transporterreference"><font colorsize="#0645ad2">dopamine transporter<span>[</span>4<span>]</span></font></asup> (The DAT1)pathway is roughly an order of magnitude faster than the NET pathway: in mice, then enzymatic breakdown by <dopamine concentrations decay with a title="Monoamine oxidase" href="/wiki/Monoamine_oxidase"><font color="#0645adhalf-life of 200 ms in the caudate nucleus (which uses the DAT1 pathway) versus 2,000 ms in the prefrontal cortex.<sup id="cite_ref-4" class="reference">monoamine oxidase</fontsize="2"></aspan> ([<a class="mw-redirect" title="MAOA" href="/wiki/MAOA"span>5<font color="#0645ad"span>MAOA]</fontspan></afont> and <a class="mw-redirect" title="MAOB" href="/wiki/MAOB"sup>Dopamine that is not broken down by enzymes is repackaged into vesicles for reuse by VMAT2.</font color="#0645ad">MAOB</fontp></adiv style="CLEAR: both">) into <a classfont color="mw-redirect" title="3,4-dihydroxyphenylacetic acid" href=#000000"></wikifont></3,4-dihydroxyphenylacetic_acid"div><h2><font colorspan id="#0645adFunctions_in_the_brain">3,4class="mw-dihydroxyphenylacetic acidheadline"><font color="#000000">Functions in the brain</font></aspan>. In </h2><p><font color="#000000">Dopamine has many functions in the prefrontal cortexbrain, however, there are very few dopamine transporter proteinsincluding important roles in behavior and cognition, voluntary movement, motivation, punishment and dopamine is instead inactivated by reuptake via the <a title="Norepinephrine transporter" href="/wiki/Norepinephrine_transporter"><font color="#0645ad">norepinephrine transporter</font></a> (NET)reward, inhibition of prolactin production (involved in lactation and sexual gratification), sleep, mood, attention, working memory, presumably on neighboring norepinephrine and learning. Dopaminergic neurons(i.e., then enzymatic breakdown by <a title="Catechol-O-methyl transferase" href="/wiki/Catechol-O-methyl_transferase">neurons whose primary neurotransmitter is dopamine) are present chiefly in the ventral tegmental area (VTA) of the midbrain, the substantia nigra pars compacta, and the arcuate nucleus of the hypothalamus.</font></p><p><font color="#0645ad000000">catechol-It has been hypothesized that dopamine transmits reward prediction error, although this has been questioned.<em>O</em>sup id="cite_ref-methyl transferasedopamine_function_5-0" class="reference"></fontsize="2"><span>[</aspan> (COMT) into 6<span>]<a class="mw-redirect" title="3-methoxytyramine" href="/wiki/3-methoxytyramine"span></font color="#0645ad">3-methoxytyramine></fontsup></a>.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><font size="2"><font color="#0645ad"><span>[</span>4<span>]</span></font></font></According to this hypothesis, the phasic responses of dopamine neurons are observed when an unexpected reward is presented. These responses transfer to the onset of a conditioned stimulus after repeated pairings with the reward. Further, dopamine neurons are depressed when the expected reward is omitted. Thus, dopamine neurons seem to encode the prediction error of rewarding outcomes. In nature, we learn to repeat behaviors that lead to maximizing rewards. Dopamine is therefore believed to provide a></sup> The DAT1 pathway is roughly an order teaching signal to parts of magnitude faster than the NET pathway: in mice, dopamine concentrations decay with brain responsible for acquiring new behavior. Temporal difference learning provides a half-life computational model describing how the prediction error of 200 ms in the caudate nucleus (which uses the DAT1 pathway) versus 2,000 ms in the prefrontal cortexdopamine neurons is used as a teaching signal.<sup id="cite_ref-4" class="reference"/font></p><a href="#cite_note-4"p><font sizecolor="2#000000">The reward system in insects uses octopamine, which is the presumed arthropod homolog of norepinephrine,<font colorsup id="#0645adcite_ref-octopamine-honeybee_6-0" class="reference"><font size="2"><span>[</span>57<span>]</span></font></font></a></sup> Dopamine that rather than dopamine. In insects, dopamine acts instead as a punishment signal and is not broken down by enzymes is repackaged into vesicles for reuse by necessary to form aversive memories.<a classsup id="mwcite_ref-pmid14627633_7-redirect0" titleclass="VMAT2" href="/wiki/VMAT2reference"><font colorsize="#0645ad2">VMAT2</fontspan>[</aspan>.8</pspan>]<div style="CLEAR: both"/span></divfont><h2/sup><span sup id="cite_ref-pmid19521527_8-0" class="editsectionreference">[<a titlefont size="Edit section: Functions in the brain" href=2"><span>[</w/index.php?title=Dopamine&amp;action=edit&amp;section=6"span>9<span>]<font color="#0645ad"/span>edit</font></asup>]</spanfont></p><h3> <span id="Functions_in_the_brainAnatomy" class="mw-headline">Functions in the brain<font color="#000000">Anatomy</font></span></h2h3><p>Dopamine has many functions in the brain, including important roles in behavior and <a titlediv class="Cognition" href="/wiki/Cognitionrellink relarticle mainarticle"><font color="#0645ad000000">cognitionMain article: Dopaminergic pathways</font></adiv>, <a title="Animal locomotion" href="/wiki/Animal_locomotion"p><font color="#0645ad000000">voluntary movement</font></a>Dopaminergic neurons form a neurotransmitter system which originates in substantia nigra pars compacta, ventral tegmental area (VTA), <a title="Motivation" href="/wiki/Motivation"><font color="#0645ad">motivation</font></a>, <a title="Punishment" href="/wiki/Punishment"><font color="#0645ad">punishment</font></a> and <a title="Reward system" href="/wiki/Reward_system"><font color="#0645ad">reward</font></a>, inhibition of <a title="Prolactin" href="/wiki/Prolactin"><font color="#0645ad">prolactin</font></a> production (involved in <a title="Lactation" href="/wiki/Lactation"><font color="#0645ad">lactation</font></a> and <a title="Prolactin" href="/wiki/Prolactin#Effects"><font color="#0645ad">sexual gratification</font></a>), <a title="Sleep" href="/wiki/Sleep"><font color="#0645ad">sleep</font></a>, <a title="Mood (psychology)" href="/wiki/Mood_(psychology)"><font color="#0645ad">mood</font></a>, <a title="Attention" href="/wiki/Attention"><font color="#0645ad">attention</font></a>, <a title="Working memory" href="/wiki/Working_memory"><font color="#0645ad">working memory</font></a>, and <a title="Learning" href="/wiki/Learning"><font color="#0645ad">learning</font></a>. Dopaminergic neurons (i.e., neurons whose primary neurotransmitter is dopamine) are present chiefly in the <a title="Ventral tegmental area" href="/wiki/Ventral_tegmental_area"><font color="#0645ad">ventral tegmental area</font></a> (VTA) of the <a title="Midbrain" href="/wiki/Midbrain"><font color="#0645ad">midbrain</font></a>, the <a title="Substantia nigra" href="/wiki/Substantia_nigra"><font color="#0645ad">substantia nigra pars compacta</font></a>, and the <a title="Arcuate nucleus" href="/wiki/Arcuate_nucleus"><font color="#0645ad">arcuate nucleus</font></a> of the hypothalamus.</p><p>It has been hypothesized that dopamine transmits reward prediction error, although this has been questioned.<sup id="cite_ref-dopamine_function_5-0" class="reference"><a href="#cite_note-dopamine_function-5"><font size="2"><font color="#0645ad"><span>[</span>6<span>]</span></font></font></a></sup> According to this hypothesis, the phasic responses of dopamine neurons are observed when an unexpected reward is presented. These responses transfer to the onset of a <a title="Classical conditioning" href="/wiki/Classical_conditioning"><font color="#0645ad">conditioned stimulus</font></a> after repeated pairings with the reward. Further, dopamine neurons are depressed when the expected reward is omitted. Thus, dopamine neurons seem to <a class="mw-redirect" title="Neural encoding" href="/wiki/Neural_encoding"><font color="#0645ad">encode</font></a> the prediction error of rewarding outcomes. In nature, we learn to repeat behaviors that lead to maximizing rewards. Dopamine is therefore believed to provide a teaching signal to parts of the brain responsible for acquiring new behavior. <a title="Temporal difference learning" href="/wiki/Temporal_difference_learning"><font color="#0645ad">Temporal difference learning</font></a> provides a computational model describing how the prediction error of dopamine neurons is used as a teaching signal.</p><p>The reward system in insects uses <a title="Octopamine" href="/wiki/Octopamine"><font color="#0645ad">octopamine</font></a>, which is the presumed arthropod homolog of <a title="Norepinephrine" href="/wiki/Norepinephrine"><font color="#0645ad">norepinephrine</font></a>,<sup id="cite_ref-octopamine-honeybee_6-0" class="reference"><a href="#cite_note-octopamine-honeybee-6"><font size="2"><font color="#0645ad"><span>[</span>7<span>]</span></font></font></a></sup> rather than dopamine. In insects, dopamine acts instead as a punishment signal and is necessary to form aversive memories.<sup id="cite_ref-pmid14627633_7-0" class="reference"><a href="#cite_note-pmid14627633-7"><font size="2"><font color="#0645ad"><span>[</span>8<span>]</span></font></font></a></sup><sup id="cite_ref-pmid19521527_8-0" class="reference"><a href="#cite_note-pmid19521527-8"><font size="2"><font color="#0645ad"><span>[</span>9<span>]</span></font></font></a></sup></p><h3><span class="editsection">[<a title="Edit section: Anatomy" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=7"><font color="#0645ad">edit</font></a>]</span> <span id="Anatomy" class="mw-headline">Anatomy</span></h3><div class="rellink relarticle mainarticle">Main article: <a title="Dopaminergic pathways" href="/wiki/Dopaminergic_pathways"><font color="#0645ad">Dopaminergic pathways</font></a></div><p><a title="Dopaminergic" href="/wiki/Dopaminergic"><font color="#0645ad">Dopaminergic</font></a> neurons form a <a class="mw-redirect" title="Neurotransmitter system" href="/wiki/Neurotransmitter_system"><font color="#0645ad">neurotransmitter system</font></a> which originates in <a class="mw-redirect" title="Substantia nigra pars compacta" href="/wiki/Substantia_nigra_pars_compacta"><font color="#0645ad">substantia nigra pars compacta</font></a>, <a title="Ventral tegmental area" href="/wiki/Ventral_tegmental_area"><font color="#0645ad">ventral tegmental area</font></a> (VTA), and <a title="Hypothalamus" href="/wiki/Hypothalamus"><font color="#0645ad">hypothalamus</font></a>. These project <a title="Axon" href="/wiki/Axon"><font color="#0645ad">axonsand hypothalamus. These project axons to large areas of the brain which are typically divided into four major pathways:</font></a> to large areas of the brain which are typically divided into four major pathways:</p>

<li><a title="Mesocortical pathway" href="/wiki/Mesocortical_pathway"><font color="#0645ad000000">Mesocortical pathway</font></a> connects the ventral tegmental area to the frontal lobe of the <a class="mw-redirect" title="Pre-frontal cortex" href="/wiki/Pre-frontal_cortex"><font color="#0645ad">pre-frontal cortex</font></a>. Neurons with <a title="Soma (biology)" href="/wiki/Soma_(biology)"><font color="#0645ad">somas</font></a> in the ventral tegmental area project axons into the pre-frontal cortex.</font></li> <li><a title="Mesolimbic pathway" href="/wiki/Mesolimbic_pathway"><font color="#0645ad000000">Mesolimbic pathway</font></a> carries dopamine from the ventral tegmental area to the <a title="Nucleus accumbens" href="/wiki/Nucleus_accumbens"><font color="#0645ad">nucleus accumbens</font></a> via the <a title="Amygdala" href="/wiki/Amygdala"><font color="#0645ad">amygdala</font></a> and <a title="Hippocampus" href="/wiki/Hippocampus"><font color="#0645ad">hippocampus</font></a>. The somas of the projecting neurons are in the ventral tegmental area.</font></li> <li><a title="Nigrostriatal pathway" href="/wiki/Nigrostriatal_pathway"><font color="#0645ad000000">Nigrostriatal pathway</font></a> runs from the substantia nigra to the <a class="mw-redirect" title="Neostriatum" href="/wiki/Neostriatum"><font color="#0645ad">neostriatum</font></a>. Somas in the substantia nigra project axons into the <a title="Caudate nucleus" href="/wiki/Caudate_nucleus"><font color="#0645ad">caudate nucleus</font></a> and <a title="Putamen" href="/wiki/Putamen"><font color="#0645ad">putamen</font></a>. The pathway is involved in the basal ganglia motor loop.</font></li> <li><a title="Tuberoinfundibular pathway" href="/wiki/Tuberoinfundibular_pathway"><font color="#0645ad000000">Tuberoinfundibular pathway</font></a> runs from the hypothalamus to the pituitary gland.</font></li>

<p><font color="#000000">This innervation explains many of the effects of activating this dopamine system. For instance, the <a title="Mesolimbic pathway" href="/wiki/Mesolimbic_pathway"><font color="#0645ad">mesolimbic pathway</font></a> connects the VTA and nucleus accumbens; both are central to the brain reward system.<a titlesup id="Nucleus accumbenscite_ref-9" hrefclass="/wiki/Nucleus_accumbensreference"><font colorsize="#0645ad2">nucleus accumbens<span>[</span>10<span>]</span></font></asup>; both are central to the brain <a title="Reward system" href="/wikifont></Reward_system"p><p><font color="#0645ad000000">reward system</font></Whilst the distinction between pathways is widely used, and is regarded as a>.<sup id="cite_ref-9" class="reference"><a href=&ldquo;convenient heuristic when considering the dopamine system&rdquo;, it is not absolute, and there is some overlap in the projection targets of each group of neurons.<sup id="#cite_notecite_ref-910" class="reference"><font size="2"><font color="#0645ad"><spanspan>[</span>1011<span>]</span></font></fontsup></a></supfont></p><ph3>Whilst the distinction between pathways is widely used, <span id="Tonic_and_phasic_activity" class="mw-headline"><font color="#000000">Tonic and phasic activity</font></span></h3><p><font color="#000000">The level of extracellular dopamine is regarded as a &ldquo;convenient heuristic when considering the dopamine system&rdquo;, it is not absolutemodulated by two mechanisms, tonic and there is some overlap in the projection targets phasic dopamine transmission. Tonic dopamine transmission occurs when small amounts of each group dopamine are released independently of neuronal activity, and is regulated by the activity of other neuronsand neurotransmitter reuptake.<sup id="cite_ref-1011" class="reference"><a href="#cite_note-10"><font size="2"><font color="#0645ad"><spanspan>[</span>1112<span>]</span></font></font></a></sup></p><h3><span class="editsection">[<a title="Edit section: Tonic and phasic Phasic dopamine release results from the activity of the dopamine-containing cells themselves. This activity" href="/w/indexis characterized by irregular pacemaking activity of single spikes, and rapid bursts of typically 2-6 spikes in quick succession.php?title<sup id=Dopamine&amp;action"cite_ref-12" class=edit&amp;section=8"reference"><font colorsize="#0645ad2">edit<span>[</fontspan>13</aspan>]</span> <span /font></sup><sup id="Tonic_and_phasic_activitycite_ref-13" class="mw-headlinereference">Tonic and phasic activity</spanfont size="2"><span>[</span>14<span>]</span></h3font><p/sup>The level Concentrated bursts of activity result in a greater increase of extracellular dopamine is modulated by two mechanisms, tonic and phasic dopamine transmissionlevels than would be expected from the same number of spikes distributed over a longer period of time. Tonic dopamine transmission occurs when small amounts of dopamine are released independently of neuronal activity, and is regulated by the activity of other neurons and neurotransmitter reuptake.<sup id="cite_ref-11" class<sup id="cite_ref-14" class="reference"><a href="#cite_note-11"><font size="2"><font color="#0645ad"><span>[</span>1215<span>]</span></font></fontsup></afont></supp><h3> Phasic dopamine release results from the activity of the dopamine-containing cells themselves. This activity is characterized by irregular <a titlespan id="Pacemaker action potentialMovement" hrefclass="/wiki/Pacemaker_action_potentialmw-headline"><font color="#0645ad000000">pacemakingMovement</font></aspan> activity of single spikes, and rapid bursts of typically 2-6 spikes in quick succession.<sup id="cite_ref-12" class="reference"/h3><a href="#cite_note-12"p><font sizecolor="2#000000"><Via the dopamine receptors, D<sub><font colorsize="#0645ad2">1-5<span/font>[</spansub>13<span>]</span></font></font></, dopamine reduces the influence of the indirect pathway, and increases the actions of the direct pathway within the basal ganglia. Insufficient dopamine biosynthesis in the dopaminergic neurons can cause Parkinson's disease, in which a><person loses the ability to execute smooth, controlled movements.</font></supp><h3><sup span id="cite_ref-13Cognition_and_frontal_cortex" class="reference"><a href="#cite_notemw-13"><font size="2headline"><font color="#0645ad000000">Cognition and frontal cortex<span/font>[</span>14<span/h3>]</spanp></fontcolor="#000000"></font></a></sup> Concentrated bursts In the frontal lobes, dopamine controls the flow of information from other areas of activity result the brain. Dopamine disorders in a greater increase this region of extracellular dopamine levels than would be expected from the same number of spikes distributed over the brain can cause a longer period of time.<sup id="cite_refdecline in neurocognitive functions, especially memory, attention, and problem-14" class="reference"><a hrefsolving. Reduced dopamine concentrations in the prefrontal cortex are thought to contribute to attention deficit disorder. It has been found that D1 receptors<sup id="#cite_notecite_ref-Inhibitorydopamine_15-140"><font sizeclass="2reference"><font colorsize="#0645ad2"><span>[</span>1516<span>]</span></font></font></asup>as well as D4 receptors</sup></p><h3><span id="cite_ref-16" class="editsectionreference">[<a titlefont size="Edit section: Movement" href=2"><span>[</w/index.php?title=Dopamine&amp;action=edit&amp;section=9"span>17<font color="#0645ad"span>edit]</fontspan></afont>]</spansup> are responsible for the cognitive-enhancing effects of dopamine.</font></p><h3> <span id="MovementRegulating_prolactin_secretion" class="mw-headline">Movement<font color="#000000">Regulating prolactin secretion</font></span></h3><p>Via the <a title="Dopamine receptor" href="/wiki/Dopamine_receptor"><font color="#0645ad000000">dopamine receptorsDopamine is the primary neuroendocrine inhibitor of the secretion of prolactin from the anterior pituitary gland.</font></a>, D<subsup id="cite_ref-prolactininhibition_17-0" class="reference"><font size="2">1-5</fontspan>[</subspan>, dopamine reduces 18<span>]</span></font></sup> Dopamine produced by neurons in the influence arcuate nucleus of the indirect pathway, and increases hypothalamus is secreted into the actions hypothalamo-hypophysial blood vessels of the direct pathway within median eminence, which supply the <a title="Basal ganglia" href="/wiki/Basal_ganglia"><font color="#0645ad">basal ganglia</font></a>pituitary gland. The lactotrope cells that produce prolactin, in the absence of dopamine, secrete prolactin continuously; dopamine inhibits this secretion. Insufficient dopamine <a title="Biosynthesis" href="Thus, in the context of regulating prolactin secretion, dopamine is occasionally called <strong>prolactin-inhibiting factor</wiki/Biosynthesis"strong>(<font color="#0645ad"strong>biosynthesisPIF</fontstrong>), <strong>prolactin-inhibiting hormone</astrong> in the dopaminergic neurons can cause (<strong>PIH<a title="Parkinson's disease" href="/wikistrong>), or <strong>prolactostatin</Parkinson%27s_disease"strong>.</font color="#0645ad">Parkinson's disease</fontp></ah3>, in which a person loses the ability to execute smooth, controlled movements.</p><h3><span class<span id="Motivation_and_pleasure" class="editsectionmw-headline">[<a title="Edit section: Cognition and frontal cortex" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=10"><font colorfont color="#0645ad">edit</font></a>]</span> <span id="Cognition_and_frontal_cortex" class="mw-headline">Cognition and frontal cortex</span></h3><p>In the <a title="Frontal lobe" href="/wiki/Frontal_lobe"><font color="#0645ad">frontal lobes</font></a>, dopamine controls the flow of information from other areas of the brain. Dopamine disorders in this region of the brain can cause a decline in <a title="Neurocognitive" href="/wiki/Neurocognitive"><font color="#0645ad">neurocognitive</font></a> functions, especially <a title="Memory" href="/wiki/Memory"><font color="#0645ad">memory</font></a>, <a title="Attention" href="/wiki/Attention"><font color="#0645ad">attention</font></a>, and <a class="mw-redirect" title="Problem-solving" href="/wiki/Problem-solving"><font color="#0645ad">problem-solving</font></a>. Reduced dopamine concentrations in the prefrontal cortex are thought to contribute to <a class="mw-redirect" title="Attention deficit disorder" href="/wiki/Attention_deficit_disorder"><font color="#0645ad">attention deficit disorder</font></a>. It has been found that D1 receptors<sup id="cite_ref-Inhibitorydopamine_15-0" class="reference"><a href="#cite_note-Inhibitorydopamine-15"><font size="2"><font color="#0645ad"><span>[</span>16<span>]</span></font></font></a></sup> as well as D4 receptors<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><font size="2"><font color="#0645ad"><span>[</span>17<span>]</span></font></font></a></sup> are responsible for the cognitive-enhancing effects of dopamine.</p><h3><span class="editsection">[<a title="Edit section: Regulating prolactin secretion" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=11"><font color="#0645ad">edit</font></a>]</span> <span id="Regulating_prolactin_secretion" class="mw-headline">Regulating prolactin secretion</span></h3><p>Dopamine is the primary <a class="mw-redirect" title="Neuroendocrine" href="/wiki/Neuroendocrine"><font color="#0645ad">neuroendocrine</font></a> inhibitor of the secretion of <a title="Prolactin" href="/wiki/Prolactin"><font color="#0645ad">prolactin</font></a> from the <a title="Anterior pituitary" href="/wiki/Anterior_pituitary"><font color="#0645ad">anterior pituitary</font></a> gland.<sup id="cite_ref-prolactininhibition_17-0" class="reference"><a href="#cite_note-prolactininhibition-17"><font size="2"><font color="#0645ad"><span>[</span>18<span>]</span></font></font></a></sup> Dopamine produced by neurons in the <a title="Arcuate nucleus" href="/wiki/Arcuate_nucleus"><font color="#0645ad">arcuate nucleus</font></a> of the hypothalamus is secreted into the hypothalamo-hypophysial blood vessels of the <a title="Median eminence" href="/wiki/Median_eminence"><font color="#0645ad">median eminence</font></a>, which supply the <a title="Pituitary gland" href="/wiki/Pituitary_gland"><font color="#0645ad">pituitary gland</font></a>. The lactotrope cells that produce <a title="Prolactin" href="/wiki/Prolactin"><font color="#0645ad">prolactin</font></a>, in the absence of dopamine, secrete prolactin continuously; dopamine inhibits this secretion. Thus, in the context of regulating prolactin secretion, dopamine is occasionally called <strong>prolactin-inhibiting factor</strong> (<strong>PIF</strong>), <strong>prolactin-inhibiting hormone</strong> (<strong>PIH</strong>), or <strong>prolactostatin</strong>.</p><h3><span class="editsection000000">[<a title="Edit section: Motivation and pleasure" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=12"><font color="#0645ad">edit</font></a>]</span> <span id="Motivation_and_pleasure" class="mw-headline">Motivation and pleasure</span></h3>

<div style="WIDTH: 222px" class="thumbinner"><a classfont color="image" href="/wiki/File:Dopamine_Pathways.png#000000"><img class="thumbimage" alt="" width="220" height="163" src="http://upload.wikimedia.org/wikipedia/commons/thumb/5/51/Dopamine_Pathways.png/220px-Dopamine_Pathways.png" width="220" height="163" /></afont>

<div class="magnify"><a classfont color="internal#000000" title><img alt="Enlarge" hrefwidth="/wiki/File:Dopamine_Pathways.png15"><img altheight="11" src="http://bits.wikimedia.org/skins-1.5/common/images/magnify-clip.png" width="15" height="11" /></afont></div><font color="#000000">Dopamine Pathways. In the brain, dopamine plays an important role in the regulation of reward and movement. As part of the reward pathway, dopamine is manufactured in nerve cell bodies located within the ventral tegmental area (VTA) and is released in the nucleus accumbens and the prefrontal cortex. Its motor functions are linked to a separate pathway, with cell bodies in the substantia nigra that manufacture and release dopamine into the striatum.</font></div>

<li><font color="#000000">Dosages from 2 to 5 &mu;g/kg/min are considered the &quot;renal dose.&quot;<sup id="cite_ref-65" class="reference"><a href="#cite_note-65"><font size="2"><font color="#0645ad"><span>[</span>66<span>]</span></font></font></a></sup> At this low dosage, dopamine binds <a title="Dopamine receptor D1" href="/wiki/Dopamine_receptor_D1"><font color="#0645ad">D_{<font size="2">1</font>}</font></a> receptors, dilating blood vessels, increasing blood flow to <a title="Renal artery" href="/wiki/Renal_artery"><font color="#0645ad">renal</font></a>, <a class="mw-redirect" title="Mesenteric artery" href="/wiki/Mesenteric_artery"><font color="#0645ad">mesenteric</font></a>, and <a class="mw-redirect" title="Coronary artery" href="/wiki/Coronary_artery"><font color="#0645ad">coronary</font></a> arteries; and increasing overall renal perfusion.<sup id="cite_ref-pharmnemonics_66-0" class="reference"><a href="#cite_note-pharmnemonics-66"><font size="2"><font color="#0645ad"><span>[</span>67<span>]</span></font></font></a></sup> Dopamine therefore has a diuretic effect, potentially increasing urine output from 5 ml/kg/hr to 10 ml/kg/hr.<sup style="WHITE-SPACE: nowrap" class="Template-Fact" title="This claim needs references to reliable sources from August 2008"><font size="2">[<em><a title="Wikipedia:Citation needed" href="/wiki/Wikipedia:Citation_needed"><font color="#0645ad">citation needed</fontem>]</afont></emsup>]</font></sup></li>

<li><font color="#000000">Intermediate dosages from 5 to 10 &mu;g/kg/min additionally have a positive <a class="mw-redirect" title="Inotropic" href="/wiki/Inotropic"><font color="#0645ad">inotropic</font></a> and <a title="Chronotropic" href="/wiki/Chronotropic"><font color="#0645ad">chronotropic</font></a> effect through increased <a title="Beta-1 adrenergic receptor" href="/wiki/Beta-1_adrenergic_receptor"><font color="#0645ad">&beta;_{<font size="2">1</font>} receptor</font></a> activation. It is used in patients with <a title="Shock (circulatory)" href="/wiki/Shock_(circulatory)"><font color="#0645ad">shock</font></a> or <a title="Heart failure" href="/wiki/Heart_failure"><font color="#0645ad">heart failure</font></a> to increase <a title="Cardiac output" href="/wiki/Cardiac_output"><font color="#0645ad">cardiac output</font></a> and <a title="Blood pressure" href="/wiki/Blood_pressure"><font color="#0645ad">blood pressure</font></a>.<sup id="cite_ref-pharmnemonics_66-1" class="reference"><a href="#cite_note-pharmnemonics-66"><font size="2"><font color="#0645ad"><span>[</span>67<span>]</span></font></font></a></sup> Dopamine begins to affect the heart at the lower doses, from about 3 &mu;g/kg/min IV.<sup id="cite_ref-67" class="reference"><a href="#cite_note-67"><font size="2"><font color="#0645ad"><span>[</span>68<span>]</span></font></fontsup></a></supfont></li>

<li><font color="#000000">High doses from 10 to 20 &mu;g/kg/min is the &quot;pressor&quot; dose.<sup style="WHITE-SPACE: nowrap" class="Template-Fact" title="This claim needs references to reliable sources from August 2008"><font size="2">[<em><a title="Wikipedia:Citation needed" href="/wiki/Wikipedia:Citation_needed"><font color="#0645ad">citation needed</font></a></em>]</font></sup> This dose causes vasoconstriction, increases <a class="mw-redirect" title="Systemic vascular resistance" href="/wiki/Systemic_vascular_resistance"><font color="#0645ad">systemic vascular resistance</font></a>, and increases blood pressure through <a class="mw-redirect" title="Alpha 1 receptor" href="/wiki/Alpha_1_receptor"><font color="#0645ad">&alpha;_{<font size="2">1</font>} receptor</font></a> activation;<sup id="cite_ref-pharmnemonics_66-2" class="reference"><a href="#cite_note-pharmnemonics-66"><font size="2"><font color="#0645ad"><span>[</span>67<span>]</span></font></font></a></sup> but can cause the vessels in the kidneys to constrict to the point where they will become non-functional.<sup style="WHITE-SPACE: nowrap" class="Template-Fact" title="This claim needs references to reliable sources from August 2008"><font size="2">[<em><a title="Wikipedia:Citation needed" href="/wiki/Wikipedia:Citation_needed"><font color="#0645ad">citation needed</fontem>]</afont></emsup>]</font></sup></li>

<h3><span classid="editsectionRenal_effects">[<a titleclass="Edit section: Renal effects" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=32mw-headline"><font color="#0645ad000000">editRenal effects</font></a>]</span> <span id="Renal_effects" class="mw-headline">Renal effects</span></h3><p>Dopamine induces <a title="Natriuresis" href="/wiki/Natriuresis"><font color="#0645ad000000">Dopamine induces natriuresis</font></a> (sodium loss) in the <a title="Kidney" href="/wiki/Kidney"><font color="#0645ad">kidneys</font></a>.<sup id="cite_ref-68" class="reference"><a href="#cite_note-68"><font size="2"><font color="#0645ad"><span>[</span>69<span>]</span></font></font></a></sup><sup id="cite_ref-69" class="reference"><a href="#cite_note-69"><font size="2"><font color="#0645ad"><span>[</span>70<span>]</span></font></fontsup></a></supfont></p><h2><span classid="editsectionDopamine_and_fruit_browning">[<a titleclass="Edit section: Dopamine and fruit browning" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=33mw-headline"><font color="#0645ad000000">editDopamine and fruit browning</font></a>]</span> <span id="Dopamine_and_fruit_browning" class="mw-headline">Dopamine and fruit browning</span></h2><p><a title="Polyphenol oxidase" href="/wiki/Polyphenol_oxidase"><font color="#0645ad000000">Polyphenol oxidases</font></a> (PPOs) are a family of enzymes responsible for the <a title="Browning (chemical process)" href="/wiki/Browning_(chemical_process)"><font color="#0645ad">browning</font></a> of fresh fruits and vegetables when they are cut or bruised. These enzymes use molecular <a title="Oxygen" href="/wiki/Oxygen"><font color="#0645ad">oxygen</font></a> (O_{<font size="2">2</font>}) to <a title="Redox" href="/wiki/Redox"><font color="#0645ad">oxidise</font></a> various <a class="mw-redirect" title="Diphenol" href="/wiki/Diphenol"><font color="#0645ad">1,2-diphenols</font></a> to their corresponding <a title="Quinone" href="/wiki/Quinone"><font color="#0645ad">quinones</font></a>. The natural substrate for PPOs in <a title="Banana" href="/wiki/Banana"><font color="#0645ad">bananas</font></a> is dopamine. The product of their oxidation, dopamine quinone, spontaneously oxidises to other quinones. The quinones then <a class="mw-redirect" title="Polymerisation" href="/wiki/Polymerisation"><font color="#0645ad">polymerise</font></a> and <a class="mw-redirect" title="Condense" href="/wiki/Condense"><font color="#0645ad">condense</font></a> with <a title="Amino acid" href="/wiki/Amino_acid"><font color="#0645ad">amino acids</font></a> and <a title="Protein" href="/wiki/Protein"><font color="#0645ad">proteins</font></a> to form brown <a title="Biological pigment" href="/wiki/Biological_pigment"><font color="#0645ad">pigments</font></a> known as <a title="Melanin" href="/wiki/Melanin"><font color="#0645ad">melanins</font></a>. The quinones and melanins derived from dopamine may help protect damaged fruit and vegetables against growth of <a title="Bacteria" href="/wiki/Bacteria"><font color="#0645ad">bacteria</font></a> and <a class="mw-redirect" title="Fungi" href="/wiki/Fungi"><font color="#0645ad">fungi</font></a>.<sup id="cite_ref-mayer_70-0" class="reference"><a href="#cite_note-mayer-70"><font size="2"><font color="#0645ad"><span>[</span>71<span>]</span></font></fontsup></a></supfont></p><h2><span classid="editsectionSee_also">[<a titleclass="Edit section: See also" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=34mw-headline"><font color="#0645ad000000">editSee also</font></a>]</span> <span id="See_also" class="mw-headline">See also</span></h2>

<li><a title="Substance use disorder" href="/wiki/Substance_use_disorder"><font color="#0645ad000000">Addiction</font></a></li> <li><a title="Amphetamine" href="/wiki/Amphetamine"><font color="#0645ad000000">Amphetamine</font></a></li> <li><a title="Antipsychotic" href="/wiki/Antipsychotic"><font color="#0645ad000000">Antipsychotic</font></a></li> <li><a title="Catecholamine" href="/wiki/Catecholamine"><font color="#0645ad000000">Catecholamine</font></a></li> <li><a title="Catechol-O-methyl transferase" href="/wiki/Catechol-O-methyl_transferase"><font color="#0645ad000000">Catechol-O-methyl transferase</font></a></li> <li><a title="Classical conditioning" href="/wiki/Classical_conditioning"><font color="#0645ad000000">Classical conditioning</font></a></li> <li><a title="Operant conditioning" href="/wiki/Operant_conditioning"><font color="#0645ad000000">Operant conditioning</font></a></li> <li><a title="Cocaine" href="/wiki/Cocaine"><font color="#0645ad000000">Cocaine</font></a></li> <li><a title="Depression (mood)" href="/wiki/Depression_(mood)"><font color="#0645ad000000">Depression</font></a></li> <li><a title="Dopamine hypothesis of schizophrenia" href="/wiki/Dopamine_hypothesis_of_schizophrenia"><font color="#0645ad000000">Dopamine hypothesis of schizophrenia</font></a></li> <li><a title="Dopamine reuptake inhibitor" href="/wiki/Dopamine_reuptake_inhibitor"><font color="#0645ad000000">Dopamine reuptake inhibitors</font></a></li> <li><a title="Dopaminergic" href="/wiki/Dopaminergic"><font color="#0645ad000000">Dopaminergic</font></a></li> <li><a title="Methylphenidate" href="/wiki/Methylphenidate"><font color="#0645ad000000">Methylphenidate</font></a></li> <li><a title="Neurotransmitter" href="/wiki/Neurotransmitter"><font color="#0645ad000000">Neurotransmitter</font></a></li> <li><a title="Parkinson's disease" href="/wiki/Parkinson%27s_disease"><font color="#0645ad000000">Parkinson's disease</font></a></li> <li><a title="Prolactinoma" href="/wiki/Prolactinoma"><font color="#0645ad000000">Prolactinoma</font></a></li> <li><a title="Schizophrenia" href="/wiki/Schizophrenia"><font color="#0645ad000000">Schizophrenia</font></a></li> <li><a title="Selegiline" href="/wiki/Selegiline"><font color="#0645ad000000">Selegiline</font></a></li> <li><a title="Serotonin" href="/wiki/Serotonin"><font color="#0645ad000000">Serotonin</font></a></li>

<h2><span class="editsection">[<a title="Edit section: References" href="/w/index.php?title=Dopamine&amp;action=edit&amp;section=35"><font color="#0645ad">edit</font></a>]</span> <span id="References" class="mw-headline">References</span></h2>

<li id="cite_note-0"><strong><a href="#cite_ref-0"><font color="#0645ad">^</font></a></strong> <a class="external free" href="http://www.encyclopedia.com/doc/1O87 <li id="cite_note-0"><strong><font color="#0645ad">^</font></strong> <font color="#3366bb">http://www.encyclopedia.com/doc/1O87-ventraltegmentalarea.html</font> Reference for VTA. </li> 

<p><table style="BORDER-BOTTOM: #aaa 1px solid&nbsp; BORDER-LEFT: #aaa 1px solid; BACKGROUND-COLOR: #f9f9f9; BORDER-TOP: #aaa 1px solid; BORDER-RIGHT: #aaa 1px solid" class="metadata mbox-small plainlinks"> <tbody> <tr> <td class="mbox-image"><img alt="" src="http://upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Wiktionary-logo-en.svg/37px-Wiktionary-logo-en.svg.png" width="37" height="40" /></td> <td class="mbox-text">Look up <em><strong><a class="extiw" title="wiktionary:Dopamine" href="http://en.wiktionary.org/wiki/Dopamine"><font color="#3366bb">Dopamine</font></a></strong></em> in <a title="Wiktionary" href="/wiki/Wiktionary"><font color="#0645ad">Wiktionary</font></a>, the free dictionary.</td> </tr> </tbody></table></p>

<li><a title="DrugBank" href="/wiki/DrugBank"><font color="#0645ad">DrugBank</font></a> <a class="external text" rel="nofollow" href="http://redpoll.pharmacy.ualberta.ca/drugbank/cgi-bin/getCard.cgi?CARD=APRD00085.txt" rel="nofollow"><font color="#3366bb">APRD00085</font></a></li> <li><a class="external text" rel="nofollow" href="http://druginfo.nlm.nih.gov/drugportal/dpdirect.jsp?name=Dopamine" rel="nofollow"><font color="#3366bb">U.S. National Library of Medicine: Drug Information Portal - Dopamine</font></a></li>