title: Fimbria-fornix transections selectively down-regulate subtypes of glutamate transporter and glutamate receptor proteins in septum and hippocampus.
abstract: The effects of CNS axotomy on glutamate transporter and glutamate receptor expression were evaluated in adult rats following unilateral fimbria-fornix transections. The septum and hippocampus were collected at 3, 7, 14, and 30 days postlesion. Homogenates were immunoblotted by using antibodies directed against glutamate transporters (GLT-1, GLAST, and EAAC1) and glutamate receptors (GluR1, GluR2/3, GluR6/7, and NMDAR1), and they were assayed for glutamate transport by D-[3H]aspartate binding. GLT-1 was decreased at 7 and 14 days postlesion within the ipsilateral septum and at 7 days postlesion in the hippocampus. GLAST was decreased within the ipsilateral septum and hippocampus at 7 and 14 days postlesion. No postlesion alterations in EAAC1 immunoreactivity were observed. D-[3H]Aspartate binding was decreased at 7, 14, and 30 days postlesion within the ipsilateral septum and 14 days postlesion in the hippocampus. GluR2/3 expression was down-regulated at 30 days postlesion within the ipsilateral septum, whereas GluR1, GluR6/7, and NMDAR1 immunoreactivity was unchanged. In addition, no alterations in glutamate receptor expression were detected within hippocampal homogenates. This study demonstrates a selective down-regulation of primarily glial, and not neuronal, glutamate transporters and a delayed, subtype-specific down-regulation of septal GluR2/3 receptor expression after regional deafferentation within the CNS.
authors: Neuropathology Laboratory, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: S D
authors: SD
authors: Ginsberg
authors: J D
authors: JD
authors: Rothstein
authors: D L
authors: DL
authors: Price
authors: L J
authors: LJ
authors: Martin
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D027322:Amino Acid Transport System X-AG; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001369:Axons / Q000502:physiology; D001692:Biological Transport / Q000502:physiology; D015153:Blotting, Western; D003720:Densitometry; D015536:Down-Regulation / Q000502:physiology; D006624:Hippocampus / Q000737:chemistry* / Q000601:surgery; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D012686:Septal Nuclei / Q000737:chemistry* / Q000601:surgery; D014316:Tritium
chemical_list: D018528:ATP-Binding Cassette Transporters; D027322:Amino Acid Transport System X-AG; D017470:Receptors, Glutamate; D014316:Tritium; D001224:Aspartic Acid