title: Riluzole attenuates excitatory amino acid transporter type 3 activity in Xenopus oocytes via protein kinase C inhibition.
abstract: This study aimed to evaluate the effect of riluzole on the activity of excitatory amino acid transporter type 3 (EAAT3), a neuronal glutamate transporter, and to investigate the role of protein kinase C (PKC) in this effect. EAAT3 expression was induced in Xenopus oocytes by injecting EAAT3 mRNA. Using the two-electrode voltage clamping method, membrane currents were recorded before, during, and after applying l-glutamate (30 μM) in the absence and presence of prior incubation with riluzole (0.3-100 μM). To study the effect of PKC on the riluzole-induced change in EAAT3 activity, oocytes were preincubated with 100 μM phorbol-12-myristate-13-acetate (PMA), a PKC activator, or PKC inhibitors (2 µM staurosporine and 100 µM chelerythrine) before the recording. Responses were quantified by integrating current traces and are reported in microCoulombs (μC). Riluzole reduced EAAT3 activity in a concentration-dependent manner (0.3-100 μM). Treatment of oocytes with PMA significantly increased the baseline and riluzole-reduced EAAT activity (P<0.05). In addition, treatment of oocytes with PKC inhibitors reduced basal transporter currents, but did not show a further significant decrease in the riluzole-reduced EAAT3 activity. These results suggest that riluzole reduces EAAT3 activity through PKC inhibition.
authors.affiliation: Department of Psychiatry, SMG-SNU Boramae Medical Center, Seoul, South Korea.
authors.forename: Jung-Seok
authors.initials: JS
authors.lastname: Choi
authors.forename: Jung-Hee
authors.initials: JH
authors.lastname: Ryu
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Zuo
authors.forename: Seong-Mi
authors.initials: SM
authors.lastname: Yang
authors.forename: Hye-Won
authors.initials: HW
authors.lastname: Chang
authors.forename: Sang-Hwan
authors.initials: SH
authors.lastname: Do
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D050580:Excitatory Amino Acid Transporter 3 / Q000037:antagonists & inhibitors* / Q000235:genetics; D066298:In Vitro Techniques; D008845:Microinjections; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019782:Riluzole / Q000494:pharmacology*; D014158:Transcription, Genetic; D014982:Xenopus laevis
chemical_list: D018691:Excitatory Amino Acid Antagonists; D050580:Excitatory Amino Acid Transporter 3; D012333:RNA, Messenger; D019782:Riluzole; D011493:Protein Kinase C