Long-term potentiation and contextual fear conditioning increase neuronal glutamate uptake.
Induction and expression of long-term potentiation (LTP) in area CA1 of the hippocampus require the coordinated regulation of several cellular processes. We found that LTP in area CA1 was associated with an N-methyl-D-aspartate (NMDA) receptor-dependent increase in glutamate uptake. The increase in glutamate uptake was inhibited by either removal of Na+ or addition of D,L-threo-beta-hydroxyaspartate. Dihydrokainate (DHK), a specific inhibitor of the glial glutamate transporter GLT-1, did not block the increase in glutamate uptake. LTP was also associated with a translocation of the EAAC1 glutamate transporter from the cytosol to the plasma membrane. Contextual fear conditioning increased the maximum rate (Vmax) of glutamate uptake and membrane expression of EAAC1 in area CA1. These results indicate that regulation of glutamate uptake may be important for maintaining the level of synaptic strength during long-term changes in synaptic efficacy.
Levenson
Jonathan
J
University of Houston, Department of Biology and Biochemistry, Houston, Texas 77204, USA.
Weeber
Edwin
E
Selcher
Joel C
JC
Kategaya
Lorna S
LS
Sweatt
J David
JD
Eskin
Arnold
A
D027322:Amino Acid Transport System X-AG / Q000378:metabolism; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003213:Conditioning, Psychological / Q000502:physiology*; D050580:Excitatory Amino Acid Transporter 3; D005239:Fear / Q000502:physiology*; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000378:metabolism*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D027981:Symporters
D027322:Amino Acid Transport System X-AG; D002352:Carrier Proteins; D050580:Excitatory Amino Acid Transporter 3; D050491:Glutamate Plasma Membrane Transport Proteins; D016194:Receptors, N-Methyl-D-Aspartate; C493398:Slc1a1 protein, rat; D027981:Symporters; D018698:Glutamic Acid