Na+/Ca2+ exchanger 1 alters in pyramidal cells and expresses in astrocytes of the gerbil hippocampal CA1 region after ischemia.
Alterations of immunoreactivity and protein contents of Na(+)/Ca(2+) exchanger 1 (NCX1) were observed in the gerbil hippocampus proper after 5 min of transient forebrain ischemia. NCX1 immunoreactivity was significantly changed in the hippocampal CA1 region, but not in the CA2/3 region after ischemia/reperfusion. In the sham-operated group, NCX1 immunoreactivity was mainly detected in CA1 pyramidal cells. However, 30 min after ischemia/reperfusion, NCX1 immunoreactivity was significantly decreased and then increased at 1 day after ischemia. At this time, NCX1 immunoreactivity in CA1 pyramidal cells was similar to that of the sham-operated group. At 3 days after ischemia, NCX1 immunoreactivity was significantly reduced in the CA1 region compared to that of the sham-operated group and NCX1 immunoreactivity was significantly increased again 4 days after ischemia. Thereafter, NCX1 immunoreactivity was decreased time-dependently in ischemia groups. Between 15 min and 6 h post-ischemia, NCX1 immunoreactivity was expressed in astrocytes in the strata oriens and radiatum of the CA1 region. From 3 days post-ischemia, NCX1 immunoreactivity was expressed in astrocytes in the strata oriens and radiatum. Ischemia-induced changes in NCX1 protein contents in the hippocampus proper concurred with immunohistochemical data post-ischemia. Our results suggest that changes in NCX1 in CA1 pyramidal cells and astrocytes after ischemia are associated with intracellular Na(+) concentrations and that NCX1 may induce an intracellular calcium overload, which may be related to neuronal death.
Hwang
In Koo
IK
Department of Anatomy, College of Medicine, Hallym University, Chunchon 200-702, South Korea.
Yoo
Ki-Yeon
KY
Kim
Dae Won
DW
Kang
Tae-Cheon
TC
Choi
Soo Young
SY
Kwon
Young-Guen
YG
Han
Byoung Hee
BH
Kim
Jong Sung
JS
Won
Moo Ho
MH
D000255:Adenosine Triphosphate / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D015153:Blotting, Western; D016923:Cell Death; D005786:Gene Expression Regulation / Q000502:physiology*; D005849:Gerbillinae; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006624:Hippocampus / Q000473:pathology*; D007150:Immunohistochemistry / Q000379:methods; D007511:Ischemia / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D017966:Pyramidal Cells / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*; D013997:Time Factors
D005904:Glial Fibrillary Acidic Protein; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D000255:Adenosine Triphosphate