title: Ischemic preconditioning inhibits expression of Na(+)/H(+) exchanger 1 (NHE1) in the gerbil hippocampal CA1 region after transient forebrain ischemia.
abstract: The participation of Na(+)/H(+) exchanger (NHE) in neuronal damage/death in the hippocampal CA1 region (CA1) induced by transient forebrain ischemia has not been well established, although acidosis may be involved in neuronal damage/death. In the present study, we examined the effect of ischemic preconditioning (IPC) on NHE1 immunoreactivity following a 5min of transient forebrain ischemia in gerbils. The animals used in the study were randomly assigned to four groups (sham-operated-group, ischemia-operated-group, IPC plus (+) sham-operated-group and IPC+ischemia-operated-group). IPC was induced by subjecting animals to 2min of ischemia followed by 1day of recovery. A significant neuronal loss was found in the stratum pyramidale (SP) of the CA1, not the CA2/3, of the ischemia-operated-group at 5days post-ischemia. However, in the IPC+ischemia-operated-group, neurons in the SP of the CA1 were well protected. NHE1 immunoreactivity was not detected in any regions of the CA1-3 of the sham- and IPC+sham-operated-groups. However, the immunoreactivity was apparently expressed in the SP of the CA1-3 after ischemia, and the NHE1immunoreactivity was very weak 5days after ischemia; however, at this point in time, strong NHE1immunoreactivity was found in astrocytes in the CA1. In the CA2/3, NHE1immunoreactivity was slightly changed, although NHE1immunoreactivity was expressed in the SP. In the IPC+ischemia-operated-groups, NHE1 immunoreactivity was also expressed in the SP of the CA1-3; however, the immunoreactivity was more slightly changed than that in the ischemia-operated-groups. In brief, our findings show that IPC dramatically protected CA1 pyramidal neurons and strongly inhibited NHE1 expression in the SP of the CA1 after ischemia-reperfusion. These findings suggest that the inhibition of NHE1 expression may be necessary for neuronal survival from transient ischemic damage.
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
authors.forename: Jeong-Hwi
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
authors.forename: In Hye
authors.initials: IH
authors.lastname: Kim
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
authors.forename: Ji Hyeon
authors.initials: JH
authors.lastname: Ahn
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
authors.forename: Joon Ha
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Neuroscience, College of Medicine, Korea University, Seoul 136-705, South Korea.
authors.forename: Geum-Sil
authors.initials: GS
authors.lastname: Cho
authors.affiliation: Department of Physiology, College of Medicine, Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 200-702, South Korea.
authors.forename: Bai Hui
authors.initials: BH
authors.lastname: Chen
authors.affiliation: Department of Physiology, College of Medicine, Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 200-702, South Korea.
authors.forename: Bich Na
authors.initials: BN
authors.lastname: Shin
authors.affiliation: Department of Biomedical Science,Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 200-702, South Korea.
authors.forename: Hyun-Jin
authors.initials: HJ
authors.lastname: Tae
authors.affiliation: Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea; Department of Emergency Medicine, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang 431-796, South Korea.
authors.forename: Seung Min
authors.initials: SM
authors.lastname: Park
authors.affiliation: Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea; Department of Emergency Medicine, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang 431-796, South Korea.
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Ahn
authors.affiliation: Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea; Department of Emergency Medicine, Chuncheon Sacred Heart Hospital, College of Medicine, Hallym University, Chuncheon 200-702, South Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Emergency Medicine, Sacred Heart Hospital, College of Medicine, Hallym University, Anyang 431-796, South Korea.
authors.forename: Jun Hwi
authors.initials: JH
authors.lastname: Cho
authors.affiliation: Department of Pediatrics, Chuncheon Sacred Heart Hospital, College of Medicine, Hallym University, Chuncheon 200-701, South Korea.
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Bae
authors.affiliation: Department of Occupational Therapy, Dongnam Health College, Suwon 440-714, South Korea.
authors.forename: Jun-Hwan
authors.initials: JH
authors.lastname: Yong
authors.affiliation: Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
authors.forename: Young-Myeong
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea. Electronic address: mhwon@kangwon.ac.kr.
authors.forename: Moo-Ho
authors.initials: MH
authors.lastname: Won
authors.affiliation: Department of Physiology, College of Medicine, Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 200-702, South Korea. Electronic address: yylee@hallym.ac.kr.
authors.forename: Yun Lyul
authors.initials: YL
authors.lastname: Lee
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D056547:CA1 Region, Hippocampal / Q000378:metabolism*; D005849:Gerbillinae; D002546:Ischemic Attack, Transient / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control*; D019194:Ischemic Preconditioning; D008297:Male; D017966:Pyramidal Cells / Q000378:metabolism* / Q000473:pathology; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*
chemical_list: D017923:Sodium-Hydrogen Exchangers
keywords: Glia; Ischemia–reperfusion; Ischemic preconditioning; Na(+)/H(+) exchanger; Neuronal damage/death; Neuroprotection