title: Ondansetron attenuates the activity of excitatory amino acid transporter type 3 expressed in Xenopus oocytes.
abstract: The purpose of this study was to evaluate the effect of ondansetron on excitatory amino acid transporter type 3 (EAAT3) and to elucidate the roles of protein kinase C (PKC) and phosphatidylinositol 3-kinase (PI3K) in the effect. EAAT3 was expressed in Xenopus oocytes following the injection of rat EAAT3 mRNAs. Using the two-electrode voltage clamping method, the inward currents induced by L-glutamate were measured for 1 min in the presence and absence of ondansetron (1-1000 μM). Different concentrations of L-glutamate (3-300 μM) were used to determine the kinetic characteristics of EAAT3. To identify the involvement of PKC and PI3K in the effect, oocytes were exposed to a PKC activator and to PKC inhibitors and PI3K inhibitors, and L-glutamate-induced currents were recorded. Ondansetron decreased EAAT3 activity in a dose-dependent manner. In a kinetic study, ondansetron (10 μM for 3 min) reduced Vmax, but not Km compared with the control group. The PKC activator abolished the ondansetron-induced decrease in EAAT3 activity. The PKC inhibitors (staurosporine and chelerythrine) and ondansetron had not additive or synergistic effects on EAAT3 activity. The PI3K inhibitors (wortmannin and LY294002) decreased the EAAT3 response, although there were no differences among the groups comprising ondansetron, PI3K inhibitors, and PI3K inhibitors plus ondansetron. Our results demonstrate that ondansetron attenuates EAAT3 activity and this effect seems to be mediated by PKC and PI3K.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Wonseok
authors.initials: W
authors.lastname: Hur
authors.affiliation: Department of Anesthesiology and Pain Medicine, Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Mi Kyoung
authors.initials: MK
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Hee-Pyeong
authors.initials: HP
authors.lastname: Park
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chong-Sung
authors.initials: CS
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Cheil General Hospital, Kwandong University, Seoul, Republic of Korea.
authors.forename: Hea-Jo
authors.initials: HJ
authors.lastname: Yoon
authors.affiliation: Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA.
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Zuo
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Gyeonggi-do 463-707, Republic of Korea. Electronic address: shdo@snu.ac.kr.
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*; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D017294:Ondansetron / Q000494:pharmacology*; D009865:Oocytes; D018408:Patch-Clamp Techniques; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D014982:Xenopus laevis
chemical_list: D018691:Excitatory Amino Acid Antagonists; D050580:Excitatory Amino Acid Transporter 3; D018698:Glutamic Acid; D017294:Ondansetron; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D047428:Protein Kinase Inhibitors; C493400:SLC1A1 protein, human
keywords: Chelerythrine (PubChem CID: 2703); EAAT3; Glutamate transporter; N294002 (PubChem CID: 3973); Ondansetron; Ondansetron (PubChem CID: 68647); Phorbol-12-myristate-13-acetate (PubChem CID: 27924); Phosphatidylinositol 3-kinase; Protein kinase C; Staurosporine (PubChem CID: 44259); Wortmannin (PubChem CID: 312145); Xenopus oocyte