title: Relationship between increase in astrocytic GLT-1 glutamate transport and late-LTP.
abstract: Na⁺-dependent high-affinity glutamate transporters have important roles in the maintenance of basal levels of glutamate and clearance of glutamate during synaptic transmission. Interestingly, several studies have shown that basal glutamate transport displays plasticity. Glutamate uptake increases in hippocampal slices during early long-term potentiation (E-LTP) and late long-term potentiation (L-LTP). Four issues were addressed in this research: Which glutamate transporter is responsible for the increase in glutamate uptake during L-LTP? In what cell type in the hippocampus does the increase in glutamate uptake occur? Does a single type of cell contain all the mechanisms to respond to an induction stimulus with a change in glutamate uptake? What role does the increase in glutamate uptake play during L-LTP? We have confirmed that GLT-1 is responsible for the increase in glutamate uptake during L-LTP. Also, we found that astrocytes were responsible for much, if not all, of the increase in glutamate uptake in hippocampal slices during L-LTP. Additionally, we found that cultured astrocytes alone were able to respond to an induction stimulus with an increase in glutamate uptake. Inhibition of basal glutamate uptake did not affect the induction of L-LTP, but inhibition of the increase in glutamate uptake did inhibit both the expression of L-LTP and induction of additional LTP. It seems likely that heightened glutamate transport plays an ongoing role in the ability of hippocampal circuitry to code and store information.
authors.affiliation: Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA.
authors.forename: Juan D
authors.initials: JD
authors.lastname: Pita-Almenar
authors.forename: Shengwei
authors.initials: S
authors.lastname: Zou
authors.forename: Costa M
authors.initials: CM
authors.lastname: Colbert
authors.forename: Arnold
authors.initials: A
authors.lastname: Eskin
mesh_terms: D000410:Alanine Transaminase / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001224:Aspartic Acid / Q000494:pharmacology; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology*; D001703:Biophysics; D019921:Biotinylation; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D004558:Electric Stimulation; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D027341:Excitatory Amino Acid Transporter 1 / Q000378:metabolism; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005434:Flow Cytometry; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D007608:Kainic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D021381:Protein Transport / Q000187:drug effects; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: C440256:4-methoxy-7-nitroindolinyl-glutamate; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D005904:Glial Fibrillary Acidic Protein; D005971:Glutamates; D007211:Indoles; D011810:Quinoxalines; C493395:Slc1a2 protein, rat; C493392:Slc1a3 protein, rat; D026941:Sodium Channel Blockers; C120673:benzyloxyaspartate; C474696:methyl-(4-carboxyphenyl)glycine; D005576:Colforsin; D001224:Aspartic Acid; D018698:Glutamic Acid; D013779:Tetrodotoxin; C020889:dihydrokainic acid; C056723:FG 9041; C056639:2-amino-5-phosphopentanoic acid; D000410:Alanine Transaminase; D014633:Valine; D007608:Kainic Acid; D005998:Glycine