Members of the solute carrier family 6 (SLC6) of sodium- and (sometimes chloride-) dependent neurotransmitter transporters [9,12,35] are primarily plasma membrane located and may be divided into four subfamilies that transport monoamines, GABA, glycine and neutral amino acids, plus the related bacterial NSS transporters [45]. The members of this superfamily share a structural motif of 10 TM segments that has been observed in crystal structures of the NSS bacterial homolog LeuT_Aa, a Na⁺-dependent amino acid transporter from Aquiflex aeolicus [62] and in several other transporter families structurally related to LeuT [20].

Monoamine neurotransmission is limited by perisynaptic transporters. Presynaptic monoamine transporters allow recycling of synaptically released noradrenaline, dopamine and 5-hydroxytryptamine (5-HT).

[¹²⁵I]RTI55 labels all three monoamine transporters (NET, DAT and SERT) with affinities between 0.5 and 5 nM. cocaine is an inhibitor of all three transporters with pK_i values between 6.5 and 7.2. Potential alternative splicing sites in non-coding regions of SERT and NET have been identified. A bacterial homologue of SERT shows allosteric modulation by selected anti-depressants [50].

The activity of GABA-transporters located predominantly upon neurones (GAT-1), glia (GAT-3) or both (GAT-2, BGT-1) serves to terminate phasic GABA-ergic transmission, maintain low ambient extracellular concentrations of GABA, and recycle GABA for reuse by neurones. Nonetheless, ambient concentrations of GABA are sufficient to sustain tonic inhibition mediated by high affinity GABA_A receptors in certain neuronal populations [48]. GAT1 is the predominant GABA transporter in the brain and occurs primarily upon the terminals of presynaptic neurones and to a much lesser extent upon distal astocytic processes that are in proximity to axons terminals. GAT3 resides predominantly on distal astrocytic terminals that are close to the GABAergic synapse. By contrast, BGT1 occupies an extrasynaptic location possibly along with GAT2 which has limited expression in the brain [37]. TauT is a high affinity taurine transporter involved in osmotic balance that occurs in the brain and non-neuronal tissues, such as the kidney, brush border membrane of the intestine and blood brain barrier [12,28]. CT1, which transports creatine, has a ubiquitous expression pattern, often co-localizing with creatine kinase [12].

The IC₅₀ values for GAT1-4 reported in the table reflect the range reported in the literature from studies of both human and mouse transporters. There is a tendency towards lower IC₅₀ values for the human orthologue [36]. SNAP-5114 is only weakly selective for GAT 2 and GAT3, with IC₅₀ values in the range 22 to >30 µM at GAT1 and BGT1, whereas NNC052090 has at least an order of magnitude selectivity for BGT1 [see [13,47] for reviews]. (R)-(1-{2-[tris(4-methoxyphenyl)methoxy]ethyl}pyrrolidin-2-yl)acetic acid is a recently described compound that displays 20-fold selectivity for GAT3 over GAT1 [21]. In addition to the inhibitors listed, EGYT3886 is a moderately potent, though non-selective, inhibitor of all cloned GABA transporters (IC₅₀ = 26-46 µM; [16]). Diaryloxime and diarylvinyl ether derivatives of nipecotic acid and guvacine that potently inhibit the uptake of [³H]GABA into rat synaptosomes have been described [34]. Several derivatives of exo-THPO (e.g. N-methyl-exo-THPO and N-acetyloxyethyl-exo-THPO) demonstrate selectivity as blockers of astroglial, versus neuronal, uptake of GABA [see [13,46] for reviews]. GAT3 is inhibited by physiologically relevant concentrations of Zn²⁺ [14]. Taut transports GABA, but with low affinity, but CT1 does not, although it can be engineered to do so by mutagenesis guided by LeuT as a structural template [17]. Although inhibitors of creatine transport by CT1 (e.g. β-guanidinopropionic acid, cyclocreatine, guanidinoethane sulfonic acid) are known (e.g. [15]) they insufficiently characterized to be included in the table.

Two gene products, GlyT1 and GlyT2, are known that give rise to transporters that are predominantly located on glia and neurones, respectively. Five variants of GlyT1 (a,b,c,d & e) differing in their N- and C-termini are generated by alternative promoter usage and splicing, and three splice variants of GlyT2 (a,b & c) have also been identified (see [5,19,23,52] for reviews). GlyT1 transporter isoforms expressed in glia surrounding glutamatergic synapses regulate synaptic glycine concentrations influencing NMDA receptor-mediated neurotransmission [4,22], but also are important, in early neonatal life, for regulating glycine concentrations at inhibitory glycinergic synapses [24]. Homozygous mice engineered to totally lack GlyT1 exhibit severe respiratory and motor deficiencies due to hyperactive glycinergic signalling and die within the first postnatal day [24,55]. Disruption of GlyT1 restricted to forebrain neurones is associated with enhancement of EPSCs mediated by NMDA receptors and behaviours that are suggestive of a promnesic action [63]. GlyT2 transporters localised on the axons and boutons of glycinergic neurones appear crucial for efficient transmitter loading of synaptic vesicles but may not be essential for the termination of inhibitory neurotransmission [25,44]. Mice in which GlyT2 has been deleted develop a fatal hyperekplexia phenotype during the second postnatal week [25] and mutations in the human gene encoding GlyT2 (SLC6A5) have been identified in patients with hyperekplexia (reviewed by [29]). ATB⁰⁺ (SLCA14) is a transporter for numerous dipolar and cationic amino acids and thus has a much broader substrate specificity than the glycine transporters alongside which it is grouped on the basis of structural similarity [12]. ATB⁰⁺ is expressed in various peripheral tissues [12]. By contrast PROT (SLC6A7), which is expressed only in brain in association with a subset of excitatory nerve terminals, shows specificity for the transport of L-proline.

sarcosine is a selective transportable inhibitor of GlyT1 and also a weak agonist at the glycine binding site of the NMDA receptor [66], but has no effect on GlyT2. This difference has been attributed to a single glycine residue in TM6 (serine residue in GlyT2) [58]. Inhibition of GLYT1 by the sarcosine derivatives NFPS, NPTS and Org 24598 is non-competitive [38-39]. IC₅₀ values for Org 24598 reported in the literature vary, most likely due to differences in assay conditions [6,38]. The tricyclic antidepressant amoxapine weakly inhibits GlyT2 (IC₅₀ 92 µM) with approximately 10-fold selectivity over GlyT1 [40]. The endogenous lipids arachidonic acid and anandamide exert opposing effects upon GlyT1a, inhibiting (IC₅₀ ~ 2 µM) and potentiating (EC₅₀ ~ 13 µM) transport currents, respectively [41]. N-arachidonyl-glycine, N-arachidonyl-γ-aminobutyric acid and N-arachidonyl-D-alanine have been described as endogenous non-competitive inhibitors of GlyT2a, but not GlyT1b [18,31,60]. Protons [3] and Zn²⁺ [32] act as non-competitive inhibitors of GlyT1b, with IC₅₀ values of ~100 nM and ~10 µM respectively, but neither ion affects GlyT2 (reviewed by [57]). Glycine transport by GLYT1 is inhibited by lithium, whereas GLYT2 transport is stimulated (both in the presence of Na⁺) [43].

Certain members of neutral amino acid transport family are expressed upon the apical surface of epithelial cells and are important for the absorption of amino acids from the duodenum, jejunum and ileum and their reabsorption within the proximal tubule of the nephron (i.e. B⁰AT1 (SLC6A19), SLC6A17, SLC6A18, SLC6A20). Others may function as transporters for neurotransmitters or their precursors (i.e. B⁰AT2, SLC6A17) [10].

Aragón, C; López-Corcuera, B. (2005) Glycine transporters: crucial roles of pharmacological interest revealed by gene deletion. Trends Pharmacol. Sci., 26 (6): 283-6. [PMID:15925702]

Betz, H; Gomeza, J; Armsen, W; Scholze, P; Eulenburg, V. (2006) Glycine transporters: essential regulators of synaptic transmission. Biochem. Soc. Trans., 34 (Pt 1): 55-8. [PMID:16417482]

Bridges, TM; Williams, R; Lindsley, CW. (2008) Design of potent GlyT1 inhibitors: in vitro and in vivo profiles. Curr. Opin. Mol. Ther., 10 (6): 591-601. [PMID:19051137]

Bröer, S. (2006) The SLC6 orphans are forming a family of amino acid transporters. Neurochem. Int., 48 (6-7): 559-67. [PMID:16540203]

Bröer, S. (2008) Apical transporters for neutral amino acids: physiology and pathophysiology. Physiology (Bethesda), 23: 95-103. [PMID:18400692]

Chen, NH; Reith, ME; Quick, MW. (2004) Synaptic uptake and beyond: the sodium- and chloride-dependent neurotransmitter transporter family SLC6. Pflugers Arch., 447 (5): 519-31. [PMID:12719981]

Christie, DL. (2007) Functional insights into the creatine transporter. Subcell. Biochem., 46: 99-118. [PMID:18652074]

Clausen, RP; Madsen, K; Larsson, OM; Frølund, B; Krogsgaard-Larsen, P; Schousboe, A. (2006) Structure-activity relationship and pharmacology of gamma-aminobutyric acid (GABA) transport inhibitors. Adv. Pharmacol., 54: 265-84. [PMID:17175818]

Dai, W; Vinnakota, S; Qian, X; Kunze, DL; Sarkar, HK. (1999) Molecular characterization of the human CRT-1 creatine transporter expressed in Xenopus oocytes. Arch. Biochem. Biophys., 361 (1): 75-84. [PMID:9882430]

Dalby, NO. (2003) Inhibition of gamma-aminobutyric acid uptake: anatomy, physiology and effects against epileptic seizures. Eur. J. Pharmacol., 479 (1-3): 127-37. [PMID:14612144]

Daws, LC. (2009) Unfaithful neurotransmitter transporters: focus on serotonin uptake and implications for antidepressant efficacy. Pharmacol. Ther., 121 (1): 89-99. [PMID:19022290]

Dohi, T; Morita, K; Kitayama, T; Motoyama, N; Morioka, N. (2009) Glycine transporter inhibitors as a novel drug discovery strategy for neuropathic pain. Pharmacol. Ther., 123 (1): 54-79. [PMID:19393690]

Eulenburg, V; Armsen, W; Betz, H; Gomeza, J. (2005) Glycine transporters: essential regulators of neurotransmission. Trends Biochem. Sci., 30 (6): 325-33. [PMID:15950877]

Foster, JD; Cervinski, MA; Gorentla, BK; Vaughan, RA. (2006) Regulation of the dopamine transporter by phosphorylation. Handb Exp Pharmacol,  (175): 197-214. [PMID:16722237]

Gadea, A; López-Colomé, AM. (2001) Glial transporters for glutamate, glycine, and GABA: II. GABA transporters. J. Neurosci. Res., 63 (6): 461-8. [PMID:11241581]

Gasnier, B. (2004) The SLC32 transporter, a key protein for the synaptic release of inhibitory amino acids. Pflugers Arch., 447 (5): 756-9. [PMID:12750892]

Gether, U; Andersen, PH; Larsson, OM; Schousboe, A. (2006) Neurotransmitter transporters: molecular function of important drug targets. Trends Pharmacol. Sci., 27 (7): 375-83. [PMID:16762425]

Gomeza, J; Armsen, W; Betz, H; Eulenburg, V. (2006) Lessons from the knocked-out glycine transporters. Handb Exp Pharmacol,  (175): 457-83. [PMID:16722246]

Gonzalez-Burgos, G. (2010) GABA transporter GAT1: a crucial determinant of GABAB receptor activation in cortical circuits?. Adv. Pharmacol., 58: 175-204. [PMID:20655483]

Han, X; Patters, AB; Jones, DP; Zelikovic, I; Chesney, RW. (2006) The taurine transporter: mechanisms of regulation. Acta Physiol (Oxf), 187 (1-2): 61-73. [PMID:16734743]

Harsing, LG; Juranyi, Z; Gacsalyi, I; Tapolcsanyi, P; Czompa, A; Matyus, P. (2006) Glycine transporter type-1 and its inhibitors. Curr. Med. Chem., 13 (9): 1017-44. [PMID:16611082]

Harvey, RJ; Topf, M; Harvey, K; Rees, MI. (2008) The genetics of hyperekplexia: more than startle!. Trends Genet., 24 (9): 439-47. [PMID:18707791]

Hashimoto, K. (2011) Glycine transporter-1: a new potential therapeutic target for schizophrenia. Curr. Pharm. Des., 17 (2): 112-20. [PMID:21355838]

Horstmann, S; Binder, EB. (2009) Pharmacogenomics of antidepressant drugs. Pharmacol. Ther., 124 (1): 57-73. [PMID:19563827]

Høg, S; Greenwood, JR; Madsen, KB; Larsson, OM; Frølund, B; Schousboe, A; Krogsgaard-Larsen, P; Clausen, RP. (2006) Structure-activity relationships of selective GABA uptake inhibitors. Curr Top Med Chem, 6 (17): 1861-82. [PMID:17017962]

Javitt, DC. (2009) Glycine transport inhibitors for the treatment of schizophrenia: symptom and disease modification. Curr Opin Drug Discov Devel, 12 (4): 468-78. [PMID:19562643]

Kanner, BI. (2006) Structure and function of sodium-coupled GABA and glutamate transporters. J. Membr. Biol., 213 (2): 89-100. [PMID:17417704]

Karunakaran, S; Umapathy, NS; Thangaraju, M; Hatanaka, T; Itagaki, S; Munn, DH; Prasad, PD; Ganapathy, V. (2008) Interaction of tryptophan derivatives with SLC6A14 (ATB0,+) reveals the potential of the transporter as a drug target for cancer chemotherapy. Biochem. J., 414 (3): 343-55. [PMID:18522536]

Kristensen, AS; Andersen, J; Jørgensen, TN; Sørensen, L; Eriksen, J; Loland, CJ; Strømgaard, K; Gether, U. (2011) SLC6 neurotransmitter transporters: structure, function, and regulation. Pharmacol. Rev., 63 (3): 585-640. [PMID:21752877]

Kulig, K; Szwaczkiewicz, M. (2008) The role of structure activity relationship studies in the search for new GABA uptake inhibitors. Mini Rev Med Chem, 8 (12): 1214-23. [PMID:18855736]

Lechner, SM. (2006) Glutamate-based therapeutic approaches: inhibitors of glycine transport. Curr Opin Pharmacol, 6 (1): 75-81. [PMID:16376148]

Madsen, KK; White, HS; Schousboe, A. (2010) Neuronal and non-neuronal GABA transporters as targets for antiepileptic drugs. Pharmacol. Ther., 125 (3): 394-401. [PMID:20026354]

Mazei-Robinson, MS; Blakely, RD. (2006) ADHD and the dopamine transporter: are there reasons to pay attention?. Handb Exp Pharmacol,  (175): 373-415. [PMID:16722244]

Millan, MJ. (2006) Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application. Pharmacol. Ther., 110 (2): 135-370. [PMID:16522330]

Moltzen, EK; Bang-Andersen, B. (2006) Serotonin reuptake inhibitors: the corner stone in treatment of depression for half a century--a medicinal chemistry survey. Curr Top Med Chem, 6 (17): 1801-23. [PMID:17017959]

Richerson, GB; Wu, Y. (2004) Role of the GABA transporter in epilepsy. Adv. Exp. Med. Biol., 548: 76-91. [PMID:15250587]

Runyon, SP; Carroll, FI. (2006) Dopamine transporter ligands: recent developments and therapeutic potential. Curr Top Med Chem, 6 (17): 1825-43. [PMID:17017960]

Saier, MH; Yen, MR; Noto, K; Tamang, DG; Elkan, C. (2009) The Transporter Classification Database: recent advances. Nucleic Acids Res., 37 (Database issue): D274-8. [PMID:19022853]

Sarup, A; Larsson, OM; Schousboe, A. (2003) GABA transporters and GABA-transaminase as drug targets. Curr Drug Targets CNS Neurol Disord, 2 (4): 269-77. [PMID:12871037]

Sałat, K; Kulig, K. (2011) GABA transporters as targets for new drugs. Future Med Chem, 3 (2): 211-22. [PMID:21428816]

Schousboe, A; Madsen, KK; White, HS. (2011) GABA transport inhibitors and seizure protection: the past and future. Future Med Chem, 3 (2): 183-7. [PMID:21428813]

Schousboe, A; Sarup, A; Bak, LK; Waagepetersen, HS; Larsson, OM. (2004) Role of astrocytic transport processes in glutamatergic and GABAergic neurotransmission. Neurochem. Int., 45 (4): 521-7. [PMID:15186918]

Schousboe, A; Sarup, A; Larsson, OM; White, HS. (2004) GABA transporters as drug targets for modulation of GABAergic activity. Biochem. Pharmacol., 68 (8): 1557-63. [PMID:15451399]

Semyanov, A; Walker, MC; Kullmann, DM; Silver, RA. (2004) Tonically active GABA A receptors: modulating gain and maintaining the tone. Trends Neurosci., 27 (5): 262-9. [PMID:15111008]

Soudijn, W; van Wijngaarden, I. (2000) The GABA transporter and its inhibitors. Curr. Med. Chem., 7 (10): 1063-79. [PMID:10911018]

Supplisson, S; Roux, MJ. (2002) Why glycine transporters have different stoichiometries. FEBS Lett., 529 (1): 93-101. [PMID:12354619]

Sur, C; Kinney, GG. (2007) Glycine transporter 1 inhibitors and modulation of NMDA receptor-mediated excitatory neurotransmission. Curr Drug Targets, 8 (5): 643-9. [PMID:17504107]

Torres, GE; Gainetdinov, RR; Caron, MG. (2003) Plasma membrane monoamine transporters: structure, regulation and function. Nat. Rev. Neurosci., 4 (1): 13-25. [PMID:12511858]

Vandenberg, RJ; Ju, P; Aubrey, KR; Ryan, RM; Mitrovic, AD. (2004) Allosteric modulation of neurotransmitter transporters at excitatory synapses. Eur J Pharm Sci, 23 (1): 1-11. [PMID:15324920]

Wang, CI; Lewis, RJ. (2010) Emerging structure-function relationships defining monoamine NSS transporter substrate and ligand affinity. Biochem. Pharmacol., 79 (8): 1083-91. [PMID:19954741]

Williams, JM; Galli, A. (2006) The dopamine transporter: a vigilant border control for psychostimulant action. Handb Exp Pharmacol,  (175): 215-32. [PMID:16722238]

Wolkenberg, SE; Sur, C. (2010) Recent progress in the discovery of non-sarcosine based GlyT1 inhibitors. Curr Top Med Chem, 10 (2): 170-86. [PMID:20166956]

Zafra, F; Giménez, C. (2008) Glycine transporters and synaptic function. IUBMB Life, 60 (12): 810-7. [PMID:18798526]

1. Anderson, CM; Ganapathy, V; Thwaites, DT. (2008) Human solute carrier SLC6A14 is the beta-alanine carrier. J. Physiol. (Lond.), 586 (Pt 17): 4061-7. [PMID:18599538]

2. Anderson, CM; Howard, A; Walters, JR; Ganapathy, V; Thwaites, DT. (2009) Taurine uptake across the human intestinal brush-border membrane is via two transporters: H+-coupled PAT1 (SLC36A1) and Na+- and Cl(-)-dependent TauT (SLC6A6). J. Physiol. (Lond.), 587 (Pt 4): 731-44. [PMID:19074966]

3. Aubrey, KR; Mitrovic, AD; Vandenberg, RJ. (2000) Molecular basis for proton regulation of glycine transport by glycine transporter subtype 1b. Mol. Pharmacol., 58 (1): 129-35. [PMID:10860934]

4. Bergeron, R; Meyer, TM; Coyle, JT; Greene, RW. (1998) Modulation of N-methyl-D-aspartate receptor function by glycine transport. Proc. Natl. Acad. Sci. U.S.A., 95 (26): 15730-4. [PMID:9861038]

5. Betz, H; Gomeza, J; Armsen, W; Scholze, P; Eulenburg, V. (2006) Glycine transporters: essential regulators of synaptic transmission. Biochem. Soc. Trans., 34 (Pt 1): 55-8. [PMID:16417482]

6. Brown, A; Carlyle, I; Clark, J; Hamilton, W; Gibson, S; McGarry, G; McEachen, S; Rae, D; Thorn, S; Walker, G. (2001) Discovery and SAR of org 24598-a selective glycine uptake inhibitor. Bioorg. Med. Chem. Lett., 11 (15): 2007-9. [PMID:11454468]

7. Bröer, A; Balkrishna, S; Kottra, G; Davis, S; Oakley, A; Bröer, S. (2009) Sodium translocation by the iminoglycinuria associated imino transporter (SLC6A20). Mol. Membr. Biol., 26 (5): 333-46. [PMID:19657969]

8. Bröer, A; Tietze, N; Kowalczuk, S; Chubb, S; Munzinger, M; Bak, LK; Bröer, S. (2006) The orphan transporter v7-3 (slc6a15) is a Na+-dependent neutral amino acid transporter (B0AT2). Biochem. J., 393 (Pt 1): 421-30. [PMID:16185194]

9. Bröer, S. (2006) The SLC6 orphans are forming a family of amino acid transporters. Neurochem. Int., 48 (6-7): 559-67. [PMID:16540203]

10. Bröer, S. (2008) Apical transporters for neutral amino acids: physiology and pathophysiology. Physiology (Bethesda), 23: 95-103. [PMID:18400692]

11. Böhmer, C; Bröer, A; Munzinger, M; Kowalczuk, S; Rasko, JE; Lang, F; Bröer, S. (2005) Characterization of mouse amino acid transporter B0AT1 (slc6a19). Biochem. J., 389 (Pt 3): 745-51. [PMID:15804236]

12. Chen, NH; Reith, ME; Quick, MW. (2004) Synaptic uptake and beyond: the sodium- and chloride-dependent neurotransmitter transporter family SLC6. Pflugers Arch., 447 (5): 519-31. [PMID:12719981]

13. Clausen, RP; Madsen, K; Larsson, OM; Frølund, B; Krogsgaard-Larsen, P; Schousboe, A. (2006) Structure-activity relationship and pharmacology of gamma-aminobutyric acid (GABA) transport inhibitors. Adv. Pharmacol., 54: 265-84. [PMID:17175818]

14. Cohen-Kfir, E; Lee, W; Eskandari, S; Nelson, N. (2005) Zinc inhibition of gamma-aminobutyric acid transporter 4 (GAT4) reveals a link between excitatory and inhibitory neurotransmission. Proc. Natl. Acad. Sci. U.S.A., 102 (17): 6154-9. [PMID:15829583]

15. Dai, W; Vinnakota, S; Qian, X; Kunze, DL; Sarkar, HK. (1999) Molecular characterization of the human CRT-1 creatine transporter expressed in Xenopus oocytes. Arch. Biochem. Biophys., 361 (1): 75-84. [PMID:9882430]

16. Dhar, TG; Borden, LA; Tyagarajan, S; Smith, KE; Branchek, TA; Weinshank, RL; Gluchowski, C. (1994) Design, synthesis and evaluation of substituted triarylnipecotic acid derivatives as GABA uptake inhibitors: identification of a ligand with moderate affinity and selectivity for the cloned human GABA transporter GAT-3. J. Med. Chem., 37 (15): 2334-42. [PMID:8057281]

17. Dodd, JR; Christie, DL. (2007) Selective amino acid substitutions convert the creatine transporter to a gamma-aminobutyric acid transporter. J. Biol. Chem., 282 (21): 15528-33. [PMID:17400549]

18. Edington, AR; McKinzie, AA; Reynolds, AJ; Kassiou, M; Ryan, RM; Vandenberg, RJ. (2009) Extracellular loops 2 and 4 of GLYT2 are required for N-arachidonylglycine inhibition of glycine transport. J. Biol. Chem., 284 (52): 36424-30. [PMID:19875446]

19. Eulenburg, V; Armsen, W; Betz, H; Gomeza, J. (2005) Glycine transporters: essential regulators of neurotransmission. Trends Biochem. Sci., 30 (6): 325-33. [PMID:15950877]

20. Forrest, LR; Rudnick, G. (2009) The rocking bundle: a mechanism for ion-coupled solute flux by symmetrical transporters. Physiology (Bethesda), 24: 377-86. [PMID:19996368]

21. Fülep, GH; Hoesl, CE; Höfner, G; Wanner, KT. (2006) New highly potent GABA uptake inhibitors selective for GAT-1 and GAT-3 derived from (R)- and (S)-proline and homologous pyrrolidine-2-alkanoic acids. Eur J Med Chem, 41 (7): 809-24. [PMID:16766089]

22. Gabernet, L; Pauly-Evers, M; Schwerdel, C; Lentz, M; Bluethmann, H; Vogt, K; Alberati, D; Mohler, H; Boison, D. (2005) Enhancement of the NMDA receptor function by reduction of glycine transporter-1 expression. Neurosci. Lett., 373 (1): 79-84. [PMID:15555781]

23. Gomeza, J; Armsen, W; Betz, H; Eulenburg, V. (2006) Lessons from the knocked-out glycine transporters. Handb Exp Pharmacol,  (175): 457-83. [PMID:16722246]

24. Gomeza, J; Hülsmann, S; Ohno, K; Eulenburg, V; Szöke, K; Richter, D; Betz, H. (2003) Inactivation of the glycine transporter 1 gene discloses vital role of glial glycine uptake in glycinergic inhibition. Neuron, 40 (4): 785-96. [PMID:14622582]

25. Gomeza, J; Ohno, K; Hülsmann, S; Armsen, W; Eulenburg, V; Richter, DW; Laube, B; Betz, H. (2003) Deletion of the mouse glycine transporter 2 results in a hyperekplexia phenotype and postnatal lethality. Neuron, 40 (4): 797-806. [PMID:14622583]

26. Gu, H; Wall, SC; Rudnick, G. (1994) Stable expression of biogenic amine transporters reveals differences in inhibitor sensitivity, kinetics, and ion dependence. J. Biol. Chem., 269 (10): 7124-30. [PMID:8125921]

27. Gu, HH; Wall, S; Rudnick, G. (1996) Ion coupling stoichiometry for the norepinephrine transporter in membrane vesicles from stably transfected cells. J. Biol. Chem., 271 (12): 6911-6. [PMID:8636118]

28. Han, X; Patters, AB; Jones, DP; Zelikovic, I; Chesney, RW. (2006) The taurine transporter: mechanisms of regulation. Acta Physiol (Oxf), 187 (1-2): 61-73. [PMID:16734743]

29. Harvey, RJ; Topf, M; Harvey, K; Rees, MI. (2008) The genetics of hyperekplexia: more than startle!. Trends Genet., 24 (9): 439-47. [PMID:18707791]

30. Hatanaka, T; Nakanishi, T; Huang, W; Leibach, FH; Prasad, PD; Ganapathy, V; Ganapathy, ME. (2001) Na+ - and Cl- -coupled active transport of nitric oxide synthase inhibitors via amino acid transport system B(0,+). J. Clin. Invest., 107 (8): 1035-43. [PMID:11306607]

31. Jeong, HJ; Vandenberg, RJ; Vaughan, CW. (2010) N-arachidonyl-glycine modulates synaptic transmission in superficial dorsal horn. Br. J. Pharmacol., 161 (4): 925-35. [PMID:20860669]

32. Ju, P; Aubrey, KR; Vandenberg, RJ. (2004) Zn2+ inhibits glycine transport by glycine transporter subtype 1b. J. Biol. Chem., 279 (22): 22983-91. [PMID:15031290]

33. Karunakaran, S; Umapathy, NS; Thangaraju, M; Hatanaka, T; Itagaki, S; Munn, DH; Prasad, PD; Ganapathy, V. (2008) Interaction of tryptophan derivatives with SLC6A14 (ATB0,+) reveals the potential of the transporter as a drug target for cancer chemotherapy. Biochem. J., 414 (3): 343-55. [PMID:18522536]

34. Knutsen, LJ; Andersen, KE; Lau, J; Lundt, BF; Henry, RF; Morton, HE; Naerum, L; Petersen, H; Stephensen, H; Suzdak, PD; et al.. (1999) Synthesis of novel GABA uptake inhibitors. 3. Diaryloxime and diarylvinyl ether derivatives of nipecotic acid and guvacine as anticonvulsant agents. J. Med. Chem., 42 (18): 3447-62. [PMID:10479278]

35. Kristensen, AS; Andersen, J; Jørgensen, TN; Sørensen, L; Eriksen, J; Loland, CJ; Strømgaard, K; Gether, U. (2011) SLC6 neurotransmitter transporters: structure, function, and regulation. Pharmacol. Rev., 63 (3): 585-640. [PMID:21752877]

36. Kvist, T; Christiansen, B; Jensen, AA; Bräuner-Osborne, H. (2009) The four human gamma-aminobutyric acid (GABA) transporters: pharmacological characterization and validation of a highly efficient screening assay. Comb. Chem. High Throughput Screen., 12 (3): 241-9. [PMID:19275529]

37. Madsen, KK; White, HS; Schousboe, A. (2010) Neuronal and non-neuronal GABA transporters as targets for antiepileptic drugs. Pharmacol. Ther., 125 (3): 394-401. [PMID:20026354]

38. Mallorga, PJ; Williams, JB; Jacobson, M; Marques, R; Chaudhary, A; Conn, PJ; Pettibone, DJ; Sur, C. (2003) Pharmacology and expression analysis of glycine transporter GlyT1 with [3H]-(N-[3-(4'-fluorophenyl)-3-(4'phenylphenoxy)propyl])sarcosine. Neuropharmacology, 45 (5): 585-93. [PMID:12941372]

39. Mezler, M; Hornberger, W; Mueller, R; Schmidt, M; Amberg, MS; Amberg, W; Amberg, MS; Braje, W; Ochse, M; Schoemaker, H; et al.. (2008) Inhibitors of GlyT1 affect glycine transport via discrete binding sites. Mol. Pharmacol., 74 (6): 1705-15. [PMID:18815213]

40. Núñez, E; López-Corcuera, B; Vázquez, J; Giménez, C; Aragón, C. (2000) Differential effects of the tricyclic antidepressant amoxapine on glycine uptake mediated by the recombinant GLYT1 and GLYT2 glycine transporters. Br. J. Pharmacol., 129 (1): 200-6. [PMID:10694221]

41. Pearlman, RJ; Aubrey, KR; Vandenberg, RJ. (2003) Arachidonic acid and anandamide have opposite modulatory actions at the glycine transporter, GLYT1a. J. Neurochem., 84 (3): 592-601. [PMID:12558979]

42. Pristupa, ZB; Wilson, JM; Hoffman, BJ; Kish, SJ; Niznik, HB. (1994) Pharmacological heterogeneity of the cloned and native human dopamine transporter: disassociation of [3H]WIN 35,428 and [3H]GBR 12,935 binding. Mol. Pharmacol., 45 (1): 125-35. [PMID:8302271]

43. Pérez-Siles, G; Morreale, A; Leo-Macías, A; Pita, G; Ortíz, AR; Aragón, C; López-Corcuera, B. (2011) Molecular basis of the differential interaction with lithium of glycine transporters GLYT1 and GLYT2. J. Neurochem., 118 (2): 195-204. [PMID:21574997]

44. Rousseau, F; Aubrey, KR; Supplisson, S. (2008) The glycine transporter GlyT2 controls the dynamics of synaptic vesicle refilling in inhibitory spinal cord neurons. J. Neurosci., 28 (39): 9755-68. [PMID:18815261]

45. Saier, MH; Yen, MR; Noto, K; Tamang, DG; Elkan, C. (2009) The Transporter Classification Database: recent advances. Nucleic Acids Res., 37 (Database issue): D274-8. [PMID:19022853]

46. Schousboe, A; Madsen, KK; White, HS. (2011) GABA transport inhibitors and seizure protection: the past and future. Future Med Chem, 3 (2): 183-7. [PMID:21428813]

47. Schousboe, A; Sarup, A; Larsson, OM; White, HS. (2004) GABA transporters as drug targets for modulation of GABAergic activity. Biochem. Pharmacol., 68 (8): 1557-63. [PMID:15451399]

48. Semyanov, A; Walker, MC; Kullmann, DM; Silver, RA. (2004) Tonically active GABA A receptors: modulating gain and maintaining the tone. Trends Neurosci., 27 (5): 262-9. [PMID:15111008]

49. Singer, D; Camargo, SM; Huggel, K; Romeo, E; Danilczyk, U; Kuba, K; Chesnov, S; Caron, MG; Penninger, JM; Verrey, F. (2009) Orphan transporter SLC6A18 is renal neutral amino acid transporter B0AT3. J. Biol. Chem., 284 (30): 19953-60. [PMID:19478081]

50. Singh, SK; Yamashita, A; Gouaux, E. (2007) Antidepressant binding site in a bacterial homologue of neurotransmitter transporters. Nature, 448 (7156): 952-6. [PMID:17687333]

51. Sloan, JL; Mager, S. (1999) Cloning and functional expression of a human Na(+) and Cl(-)-dependent neutral and cationic amino acid transporter B(0+). J. Biol. Chem., 274 (34): 23740-5. [PMID:10446133]

52. Supplisson, S; Roux, MJ. (2002) Why glycine transporters have different stoichiometries. FEBS Lett., 529 (1): 93-101. [PMID:12354619]

53. Talvenheimo, J; Fishkes, H; Nelson, PJ; Rudnick, G. (1983) The serotonin transporter-imipramine "receptor". J. Biol. Chem., 258 (10): 6115-9. [PMID:6853478]

54. Tatsumi, M; Groshan, K; Blakely, RD; Richelson, E. (1997) Pharmacological profile of antidepressants and related compounds at human monoamine transporters. Eur. J. Pharmacol., 340 (2-3): 249-58. [PMID:9537821]

55. Tsai, G; Ralph-Williams, RJ; Martina, M; Bergeron, R; Berger-Sweeney, J; Dunham, KS; Jiang, Z; Caine, SB; Coyle, JT. (2004) Gene knockout of glycine transporter 1: characterization of the behavioral phenotype. Proc. Natl. Acad. Sci. U.S.A., 101 (22): 8485-90. [PMID:15159536]

56. Umapathy, NS; Ganapathy, V; Ganapathy, ME. (2004) Transport of amino acid esters and the amino-acid-based prodrug valganciclovir by the amino acid transporter ATB(0,+). Pharm. Res., 21 (7): 1303-10. [PMID:15290873]

57. Vandenberg, RJ; Ju, P; Aubrey, KR; Ryan, RM; Mitrovic, AD. (2004) Allosteric modulation of neurotransmitter transporters at excitatory synapses. Eur J Pharm Sci, 23 (1): 1-11. [PMID:15324920]

58. Vandenberg, RJ; Shaddick, K; Ju, P. (2007) Molecular basis for substrate discrimination by glycine transporters. J. Biol. Chem., 282 (19): 14447-53. [PMID:17383967]

59. Vanslambrouck, JM; Bröer, A; Thavyogarajah, T; Holst, J; Bailey, CG; Bröer, S; Rasko, JE. (2010) Renal imino acid and glycine transport system ontogeny and involvement in developmental iminoglycinuria. Biochem. J., 428 (3): 397-407. [PMID:20377526]

60. Wiles, AL; Pearlman, RJ; Rosvall, M; Aubrey, KR; Vandenberg, RJ. (2006) N-Arachidonyl-glycine inhibits the glycine transporter, GLYT2a. J. Neurochem., 99 (3): 781-6. [PMID:16899062]

61. Wong, EH; Sonders, MS; Amara, SG; Tinholt, PM; Piercey, MF; Hoffmann, WP; Hyslop, DK; Franklin, S; Porsolt, RD; Bonsignori, A; et al.. (2000) Reboxetine: a pharmacologically potent, selective, and specific norepinephrine reuptake inhibitor. Biol. Psychiatry, 47 (9): 818-29. [PMID:10812041]

62. Yamashita, A; Singh, SK; Kawate, T; Jin, Y; Gouaux, E. (2005) Crystal structure of a bacterial homologue of Na+/Cl--dependent neurotransmitter transporters. Nature, 437 (7056): 215-23. [PMID:16041361]

63. Yee, BK; Balic, E; Singer, P; Schwerdel, C; Grampp, T; Gabernet, L; Knuesel, I; Benke, D; Feldon, J; Mohler, H; et al.. (2006) Disruption of glycine transporter 1 restricted to forebrain neurons is associated with a procognitive and antipsychotic phenotypic profile. J. Neurosci., 26 (12): 3169-81. [PMID:16554468]

64. Yu, XC; Zhang, W; Oldham, A; Buxton, E; Patel, S; Nghi, N; Tran, D; Lanthorn, TH; Bomont, C; Shi, ZC; et al.. (2009) Discovery and characterization of potent small molecule inhibitors of the high affinity proline transporter. Neurosci. Lett., 451 (3): 212-6. [PMID:19159658]

65. Zaia, KA; Reimer, RJ. (2009) Synaptic Vesicle Protein NTT4/XT1 (SLC6A17) Catalyzes Na+-coupled Neutral Amino Acid Transport. J. Biol. Chem., 284 (13): 8439-48. [PMID:19147495]

66. Zhang, HX; Hyrc, K; Thio, LL. (2009) The glycine transport inhibitor sarcosine is an NMDA receptor co-agonist that differs from glycine. J. Physiol. (Lond.), 587 (Pt 13): 3207-20. [PMID:19433577]