Ischemia-related changes of glial-derived neurotrophic factor and phosphatidylinositol 3-kinase in the hippocampus: their possible correlation in astrocytes.
In the present study, we observed the changes of endogenous expression of glial-cell-line-derived neurotrophic factor (GDNF) and phosphatidylinositol 3-kinase (PI-3 kinase) in the gerbil hippocampus after transient forebrain ischemia and investigated the correlation between GDNF and PI-3 kinase in the ischemic hippocampus. In the sham-operated group, GDNF and PI-3 kinase immunoreactivity was not found in any cells in the hippocampal CA1 region. GDNF, not PI-3 kinase, immunoreactivity was expressed in non-pyramidal cells in the CA1 region at 6 h after ischemic insult. At 12-24 h after ischemia, GDNF and PI-3 kinase immunoreactivity in the CA1 region was similar to that of the sham-operated group. From 2 days after ischemic insult, GDNF- and PI-3-kinase-immunoreactive astrocytes were detected in the CA1 region, and GDNF and PI-3 kinase immunoreactivity in astrocytes was highest in the CA1 region 4 days after ischemic insult. Moreover, at this time point, GDNF and PI-3 kinase were co-localized in some astrocytes. Western blotting showed that ischemia-related changes of GDNF and PI-3 kinase protein levels were similar to the immunohistochemical changes after ischemia. These results suggest that GDNF and PI-3 kinase may be related to delayed neuronal death and that GDNF and PI-3 kinase may be involved in activation of astrocytes.
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
Lee
Bong-Hee
BH
Kang
Tae-Cheon
TC
Choi
Soo Young
SY
Han
Byoung Hee
BH
Kim
Jong Sung
JS
Won
Moo Ho
MH
D000818:Animals; D001253:Astrocytes / Q000201:enzymology / Q000378:metabolism; D002545:Brain Ischemia / Q000378:metabolism*; D004195:Disease Models, Animal; D005849:Gerbillinae; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000378:metabolism*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D012016:Reference Values
D051100:Glial Cell Line-Derived Neurotrophic Factor; D005904:Glial Fibrillary Acidic Protein; D019869:Phosphatidylinositol 3-Kinases