title: Effects of pregabalin on the activity of glutamate transporter type 3.
abstract: BACKGROUND
  Pregabalin, (S)-3-aminomethyl-5-methyl hexanoic acid, is a ligand for the α2δ subunit (a component of voltage-gated calcium channels) and has analgesic and anticonvulsant properties. Glutamate uptake by glutamate transporters may be a mechanism for these properties. We investigated the effects of pregabalin on the activity of the neuronal glutamate transporter type 3 (EAAT3).
  
  
  METHODS
  EAAT3 was expressed in Xenopus laevis oocytes. Two-electrode voltage clamping was used to record membrane currents before, during, and after applying l-glutamate (30 μM) in the presence or absence of pregabalin. Currents were also measured in oocytes pretreated with a protein kinase C (PKC) activator (phorbol-12-myristate-13-acetate, PMA), PKC inhibitors (chelerythrine or staurosporine), or a phosphatidylinositol-3-kinase (PI3K) inhibitor wortmannin.
  
  
  RESULTS
  The exposure of the oocytes injected with EAAT3 mRNA to serial concentrations of pregabalin (0.06-60 μM) significantly increased their responses to 30 μM l-glutamate. A kinetic study showed that pregabalin significantly increased V(max) without changing K(m). Treatment of oocytes with PMA, pregabalin, or pregabalin plus PMA significantly increased transporter currents vs controls, but treatment with PMA plus pregabalin did not increase the responses further vs PMA or pregabalin alone. In addition, pretreatment of oocytes with two PKC inhibitors (chelerythrine or staurosporine), or inhibitor wortmannin, significantly reduced basal and pregabalin-enhanced EAAT3 activity.
  
  
  CONCLUSIONS
  Pregabalin increased EAAT3 activity and PKC and PI3K were involved. This may explain the analgesic effect of pregabalin in neuropathic pain.
authors.affiliation: Department of Anesthesiology and Pain Medicine,  Seoul National University Bundang Hospital, Seongnam-si, Gyeonggi-do,  Republic of Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Ryu
authors.forename: P B
authors.initials: PB
authors.lastname: Lee
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: S H
authors.initials: SH
authors.lastname: Do
authors.forename: C S
authors.initials: CS
authors.lastname: Kim
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D050580:Excitatory Amino Acid Transporter 3 / Q000096:biosynthesis / Q000187:drug effects* / Q000235:genetics; D005260:Female; D008845:Microinjections / Q000379:methods; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D000069583:Pregabalin; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000494:pharmacology; D014982:Xenopus laevis; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D018712:Analgesics, Non-Narcotic; D050580:Excitatory Amino Acid Transporter 3; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D000069583:Pregabalin; D005680:gamma-Aminobutyric Acid; C016658:phorbolol myristate acetate; D013755:Tetradecanoylphorbol Acetate