Dexamethasone inhibits ischemia-induced transient reduction of neurotrophin-3 mRNA in rat hippocampal neurons.
Dexamethasone (DEX) increases the expression of neurotrophin-3 (NT-3) in normal rat hippocampal neurons, whereas transient forebrain ischemia reduces the NT-3 mRNA level. The effect of DEX on the expression of NT-3 mRNA in injured brain cells after ischemia has not been investigated, however. Using in situ hybridization and ribonuclease protection assay methods, we studied NT-3 mRNA expression in rats with and without DEX administration after transient forebrain ischemia. Without DEX treatment, NT-3 mRNA was down-regulated in the hippocampal neurons at 2, 4, 12 h and returned to basal levels 24 h following ischemia. With DEX treatment, however, NT-3 mRNA showed no change at 2, 4 and 12 h and increased 24 h after ischemia. The results indicate that DEX inhibits ischemia-induced NT-3 mRNA down-regulation during the first 12 h and up-regulates NT-3 mRNA 24 h after ischemia. DEX administration might be effective in influencing some of the pathophysiological effects of ischemia in the hippocampus.
Yang
J T
JT
Department of Neurosurgery, Chang Gung Memorial Hospital, Taipei, Taiwan.
Chang
C N
CN
Lee
T H
TH
Hsu
J C
JC
Lin
T N
TN
Wu
J H
JH
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology; D002545:Brain Ischemia / Q000503:physiopathology*; D018891:Dentate Gyrus / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D017403:In Situ Hybridization; D008297:Male; D009414:Nerve Growth Factors / Q000235:genetics*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D020933:Neurotrophin 3; D016548:Prosencephalon / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D000893:Anti-Inflammatory Agents; D009414:Nerve Growth Factors; D020933:Neurotrophin 3; D012333:RNA, Messenger; D003907:Dexamethasone