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AliasesSLC22A3, EMT, EMTH, OCT3, solute carrier family 22 member 3
External IDsOMIM: 604842 MGI: 1333817 HomoloGene: 22630 GeneCards: SLC22A3
Gene location (Human)
Chromosome 6 (human)
Chr.Chromosome 6 (human)[1]
Chromosome 6 (human)
Genomic location for SLC22A3
Genomic location for SLC22A3
Band6q25.3Start160,348,378 bp[1]
End160,452,577 bp[1]
RNA expression pattern
PBB GE SLC22A3 205421 at fs.png
More reference expression data
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 6: 160.35 – 160.45 MbChr 17: 12.42 – 12.51 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Solute carrier family 22 member 3 (SLC22A3) also known as the organic cation transporter 3 (OCT3) or extraneuronal monoamine transporter (EMT) is a protein that in humans is encoded by the SLC22A3 gene.[5][6][7]

Polyspecific organic cation transporters in the liver, kidney, intestine, and other organs are critical for elimination of many endogenous small organic cations as well as a wide array of drugs and environmental toxins. This gene is one of three similar cation transporter genes located in a cluster on chromosome 6. The encoded protein contains twelve putative transmembrane domains and is a plasma integral membrane protein.[7]


OCT3 is widely distributed in brain tissue. It is not yet completely clear whether its location is primarily neuronal or glial. Areas of the brain in which it has been reported include: hippocampus, retrosplenial cortex, visual cortex, hypothalamus, amygdala, nucleus accumbens, thalamus, raphe nucleus, subiculum, superior and inferior colliculi, and islands of Calleja.[8][9]


Organic cation transporter 3 is a polyspecific transporter whose transport is independent of sodium. Known substrates for transport include: histamine, serotonin, norepinephrine, dopamine and MPP+. Capacity for transport and affinity for these substrates may vary between rat and human isoforms however.[9]

Transport activity of OCT3 is inhibited by recreational and pharmaceutical drugs, including MDMA, phencyclidine (PCP), MK-801, amphetamine, methamphetamine and cocaine.[9] Transport is also inhibited by the chemical decynium-22 and physiological concentrations of corticosterone and cortisol. Ki values for decynium-22 and corticosterone inhibition of OCT3 transport are respectively 10 and 100 times lower than Ki values of OCT1 and OCT2.[10] This effect of glucocorticoids is believed to explain the phenomenon of stress-induced relapse in recovering addicts, where dopamine transport inhibition causes reactivation of hypersensitive dopamine pathways involved in drug-seeking behavior and incentive salience.

See also[edit]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000146477 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000023828 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Kekuda R, Prasad PD, Wu X, Wang H, Fei YJ, Leibach FH, Ganapathy V (Aug 1998). "Cloning and functional characterization of a potential-sensitive, polyspecific organic cation transporter (OCT3) most abundantly expressed in placenta". J Biol Chem. 273 (26): 15971–15979. doi:10.1074/jbc.273.26.15971. PMID 9632645.
  6. ^ Verhaagh S, Schweifer N, Barlow DP, Zwart R (Sep 1999). "Cloning of the mouse and human solute carrier 22a3 (Slc22a3/SLC22A3) identifies a conserved cluster of three organic cation transporters on mouse chromosome 17 and human 6q26-q27". Genomics. 55 (2): 209–218. doi:10.1006/geno.1998.5639. PMID 9933568.
  7. ^ a b "Entrez Gene: SLC22A3 solute carrier family 22 (extraneuronal monoamine transporter), member 3".
  8. ^ Gasser PJ, Orchinik M, Raju I, Lowry CA (Feb 2009). "Distribution of organic cation transporter 3, a corticosterone-sensitive monoamine transporter, in the rat brain". J Comp Neurol. 512 (4): 529–555. doi:10.1002/cne.21921. PMID 19025979. S2CID 33389900.
  9. ^ a b c Amphoux A, Vialou V, Drescher E, Brüss M, Mannoury La Cour C, Rochat C, Millan MJ, Giros B, Bönisch H, Gautron S (Jun 2006). "Differential pharmacological in vitro properties of organic cation transporters and regional distribution in rat brain". Neuropharmacology. 50 (8): 941–952. doi:10.1016/j.neuropharm.2006.01.005. PMID 16581093. S2CID 42204368.
  10. ^ Hayer-Zillgen M, Brüss M, Bönisch H (Jul 2002). "Expression and pharmacological profile of the human organic cation transporters hOCT1, hOCT2 and hOCT3". Br J Pharmacol. 136 (6): 829–836. doi:10.1038/sj.bjp.0704785. PMC 1573414. PMID 12110607.

Further reading[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.