title: Pharmacological enhancement of glutamate transport reduces excitotoxicity in vitro.
abstract: OBJECTIVE
  Glutamate transporters are responsible for removing glutamate from the extracellular space and have the potential to protect neurons from excitotoxicity. In the present study, the effects of ceftriaxone and (2R, 4R)-APDC (APDC) on the protein expression of GLAST and GLT-1, the rate of glutamate uptake, and neuroprotection were evaluated in a cell culture model of glutamate excitotoxicity.
  
  
  METHODS
  Mixed neuron/astrocyte cultures were prepared from 1 day old rat pups. Protein levels of GLAST and GLT-1 glutamate transporters were quantified using In-Cell Western techniques after acute or 5-day treatment with either ceftriaxone or APDC. Glutamate uptake was measured using Michaelis-Menten kinetics to evaluate the effects of 5-day treatment with ceftriaxone or APDC. Neuronal cell death in response to a 10-minute 1 mM glutamate challenge was measured following 5-day treatment with either ceftriaxone or APDC.
  
  
  RESULTS
  Five-day treatment with 100 μM ceftriaxone significantly increased both GLAST and GLT-1 protein levels 31.3% and 47.5% above control, respectively, increased the Vmax 29.3%, increased the Km of glutamate uptake 117.9%, and reduced neuronal death 22.0% after a 1 mM glutamate challenge. Five-day treatment with 1 mM APDC significantly increased GLAST protein levels 27.6%, increased the Vmax 92.4%, increased the Km of glutamate transport 118.9%, and decreased neuronal death 36.8% after a 1 mM glutamate challenge.
  
  
  CONCLUSIONS
  Chronic treatment with ceftriaxone or APDC provided neuroprotection from glutamate excitotoxicity while increasing GLAST and GLT-1 protein levels and increasing glutamate uptake. These compounds may have therapeutic potential in chronic excitotoxic neurodegenerative diseases.
authors.affiliation: Department of Neurological Surgery, University of California, Davis, USA.
authors.forename: Justin A
authors.initials: JA
authors.lastname: Beller
authors.forename: Gene G
authors.initials: GG
authors.lastname: Gurkoff
authors.forename: Robert F
authors.initials: RF
authors.lastname: Berman
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Lyeth
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002443:Ceftriaxone / Q000494:pharmacology; D002478:Cells, Cultured; D018920:Coculture Techniques; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism* / Q000633:toxicity*; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology; D009498:Neurotoxins / Q000037:antagonists & inhibitors* / Q000378:metabolism* / Q000633:toxicity; D011392:Proline / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation / Q000187:drug effects* / Q000502:physiology
chemical_list: C097299:4-aminopyrrolidine-2,4-dicarboxylic acid; D000900:Anti-Bacterial Agents; D027341:Excitatory Amino Acid Transporter 1; D051272:Glucose Transporter Type 1; D009498:Neurotoxins; C493392:Slc1a3 protein, rat; C495679:Slc2a1 protein, rat; D018698:Glutamic Acid; D002443:Ceftriaxone; D011392:Proline