title: High expression of GLT-1 in hippocampal CA3 and dentate gyrus subfields contributes to their inherent resistance to ischemia in rats.
abstract: It is well known that neurons in the CA3 and dentate gyrus (DG) subfields of the hippocampus are resistant to short period of ischemia which is usually lethal to pyramidal neurons in hippocampal CA1 subfield. The present study was undertaken to clarify whether the inherent higher resistance of neurons in CA3 and DG to ischemia is associated with glial glutamate transporter-1 (GLT-1) in rats. Western blot analysis and immunohistochemistry assay showed that the basal expressions of GLT-1 in both CA3 and DG were much higher than that in CA1 subfield. Mild global brain ischemia for 8 min induced delayed death of almost all CA1 pyramidal neurons and marked GLT-1 down-regulation in the CA1 subfield, but it was not lethal to the neurons in either CA3 or DG and induced GLT-1 up-regulation and astrocyte activation showed normal soma and aplenty slender processes in the both areas. When the global brain ischemia was prolonged to 25 min, neuronal death was clearly observed in CA3 and DG accompanied with down-regulation of GLT-1 expression and abnormal astrocytes represented with hypertrophic somas, but shortened processes. After down-regulating of GLT-1 expression and function by its antisense oligodeoxynucleotides or inhibiting GLT-1 function by dihydrokainate, an inhibitor of GLT-1, the mild global brain ischemia for 8 min, which usually was not lethal to CA3 and DG neurons, induced the neuronal death in CA3 and DG subfields. Taken together, the higher expression of GLT-1 in the CA3 and DG contributes to their inherent resistance to ischemia.
authors.affiliation: Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang 050017, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Li
authors.forename: Yi-Xian
authors.initials: YX
authors.lastname: Liu
authors.forename: Cui-Juan
authors.initials: CJ
authors.lastname: Liang
authors.forename: Li-Zhe
authors.initials: LZ
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Cui
authors.forename: Jian-Xue
authors.initials: JX
authors.lastname: Gong
authors.forename: Shu-Juan
authors.initials: SJ
authors.lastname: Gong
authors.forename: Yu-Yan
authors.initials: YY
authors.lastname: Hu
authors.forename: Xiao-Hui
authors.initials: XH
authors.lastname: Xian
mesh_terms: D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002545:Brain Ischemia / Q000378:metabolism*; D017931:DNA Primers; D018891:Dentate Gyrus / Q000378:metabolism*; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D007150:Immunohistochemistry; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D017931:DNA Primers; D027342:Excitatory Amino Acid Transporter 2