Ischemic preconditioning upregulates expression of phospholipase D2 in the rat hippocampus.
To investigate the possible involvement of phospholipase D2 (PLD2) in the induction of ischemic tolerance, we analyzed the distribution and time course of PLD2 expression in the rat hippocampus after a sublethal period of ischemia. Forebrain ischemia was induced by four-vessel occlusion for 3 min. Increased PLD2 immunoreactivity after this sublethal ischemia was observed in CA1 pyramidal neurons of the rat hippocampus. In tolerance-acquired CA1 neurons, PLD2 immunoreactivity was upregulated as early as 12 h post-ischemia and was most prominent at 1-3 days, with expression sustained for at least 7 days, as shown by a time course of immunoblotting and measurement of the enzymatic activity of PLD. PLD2 expression was also increased in ischemia-resistant CA3 neurons and dentate granule cells, although weaker staining intensity was noted. Further, we showed that, in cultured SK-N-BE(2)C human neuroblastoma cells, overexpression of PLD2 inhibited cell death by chemical hypoxia induced with potassium cyanide and deoxyglucose. These data suggest that upregulation of PLD2 might be involved in the neuroprotective mechanism of ischemic tolerance in the rat hippocampus.
Min
Do Sik
do S
Department of Molecular Biology, College of Natural Science, Pusan National University, Busan, 609-735, South Korea.
Choi
Jeong-Sun
JS
Kim
Ha-Young
HY
Shin
Min Kyoung
MK
Kim
Mi Kyoung
MK
Lee
Mun-Yong
MY
D000818:Animals; D015153:Blotting, Western; D002545:Brain Ischemia / Q000201:enzymology* / Q000503:physiopathology; D045744:Cell Line, Tumor; D006624:Hippocampus / Q000098:blood supply* / Q000201:enzymology*; D006801:Humans; D007150:Immunohistochemistry; D019194:Ischemic Preconditioning; D008297:Male; D010739:Phospholipase D / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000201:enzymology / Q000503:physiopathology; D015854:Up-Regulation
C105606:phospholipase D2; D010739:Phospholipase D