AMPA-mediated excitotoxicity in oligodendrocytes: role for Na(+)-K(+)-Cl(-) co-transport and reversal of Na(+)/Ca(2+) exchanger.
We investigated the role of Na(+)-K(+)-Cl(-) co-transporter isoform 1 (NKCC1) and reversal of Na(+)/Ca(2+) exchanger (NCX(rev)) in glutamate-mediated excitotoxicity in oligodendrocytes obtained from rat spinal cords (postnatal day 6-8). An immunocytochemical characterization showed that these cultures express NKCC1 and Na(+)/Ca(2+) exchanger isoforms 1, 2, and 3 (NCX1, NCX2, NCX3). Exposing the cultures to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) plus cyclothiazide (CTZ) led to a transient rise in intracellular (), which was followed by a sustained overload, NKCC1 phosphorylation, and a NKCC1-mediated Na(+) influx. In the presence of a specific AMPA receptor inhibitor 6-cyano-7-nitroquinoxaline-2, 3-dione (CNQX), the AMPA/CTZ failed to elicit any changes in . The AMPA/CTZ-induced sustained rise led to mitochondrial Ca(2+) accumulation, release of cytochrome c from mitochondria, and cell death. The AMPA/CTZ-elicited increase, mitochondrial damage, and cell death were significantly reduced by inhibiting NKCC1 or NCX(rev). These data suggest that in cultured oligodendrocytes, activation of AMPA receptors leads to NKCC1 phosphorylation that enhances NKCC1-mediated Na(+) influx. The latter triggers NCX(rev) and NCX(rev)-mediated overload and compromises mitochondrial function and cellular viability.
Chen
Hai
H
Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA.
Kintner
Douglas B
DB
Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA.
Jones
Mathew
M
Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA.
Matsuda
Toshio
T
Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA.
Baba
Akemichi
A
Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA.
Kiedrowski
Lech
L
Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA.
Sun
Dandan
D
Neuroscience Training Program, University of Wisconsin Medical School, Madison, Wisconsin, USADepartments of Neurosurgery, University of Wisconsin Medical School, Madison, Wisconsin, USAPhysiology, University of Wisconsin Medical School, Madison, Wisconsin, USAGraduate School of Pharmaceutical Sciences, Osaka University, Osaka, JapanDepartments of Psychiatry and Pharmacology, University of Illinois at Chicago, Illinois, USA.
D000818:Animals; D000831:Animals, Newborn; D000959:Antihypertensive Agents / Q000494:pharmacology; D001581:Benzothiadiazines / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002490:Central Nervous System / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism / Q000633:toxicity; D026901:Membrane Transport Proteins / Q000187:drug effects / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009498:Neurotoxins / Q000378:metabolism* / Q000633:toxicity; D009836:Oligodendroglia / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000187:drug effects / Q000378:metabolism*; D028021:Sodium-Potassium-Chloride Symporters / Q000187:drug effects / Q000378:metabolism*; D064506:Solute Carrier Family 12, Member 2; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D000959:Antihypertensive Agents; D001581:Benzothiadiazines; D018690:Excitatory Amino Acid Agonists; D026901:Membrane Transport Proteins; D009498:Neurotoxins; D018091:Receptors, AMPA; C578879:Slc12a2 protein, rat; C110927:Slc8a2 protein, rat; C491102:Slc8a3 protein, rat; D019831:Sodium-Calcium Exchanger; D028021:Sodium-Potassium-Chloride Symporters; D064506:Solute Carrier Family 12, Member 2; C110374:sodium-calcium exchanger 1; D018698:Glutamic Acid; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D012964:Sodium; C004639:cyclothiazide; D002118:Calcium