[Dephosphorelation of Bad and upregulation of Bcl-2 in hippocampus of rats following limbic seizure induced by kainic acid injection into amygdaloid nucleus].
The purpose of the present study was to explore the seizure-induced changes in Bad (Bcl-2-associated death protein), 14-3-3, phosphoBad, Bcl-2 and Bcl-XL expression in the rat model of focal limbic seizure. Unilateral intra-amygdaloid injection of kainic acid (KA) was made to induce seizure. Electroencephalogram (EEG) and regional cerebral flow (r-CBF) were monitored continuously. Diazepam (30 mg/kg) was administered to terminate the seizure. The apoptotic and surviving neurons in the hippocampus were observed by terminal deoxynucleotidyl transferrase-mediated dUTP nick end labeling (TUNEL) and cresyl violet staining, the expression of Bad, 14-3-3, phosphoBad, Bcl-2 and Bcl-XL were detected with immunofluorescence, Western blot and immunoprecipitation. The results showed that TUNEL-positive neurons appeared at 8 h and reached maximum at 24 h following seizure cessation within the ipsilateral CA3 subfield of the hippocampus. Seizure induced the dephosphorylation of Bad and the dissociation of Bad from its chaperone protein 14-3-3 and subsequent dimerization of Bad with Bcl-XL. The expression of phosphoBad decreased and Bcl-2 increased. There was little change in r-CBF after the seizure. These results suggest that seizure leads to a dephosphorylation of Bad and an upregulation of Bcl-2. Dephosphorylation of Bad may be injurious while the upregulation of Bcl-2 may be protective to the brain damage induced by seizures, but not related with r-CBF.
Li
Tian-Fu
TF
Department of Neurology, Affiliated Hospital of Taishan Medical College, Taian 271000, China. tianfuli88@hotmail.com
Lu
Chuan-Zhen
CZ
Xia
Zuo-Li
ZL
Niu
Jing-Zhong
JZ
Yang
Ming-Feng
MF
Luo
Yu-Min
YM
Hong
Zhen
Z
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D004828:Epilepsies, Partial / Q000139:chemically induced / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D007608:Kainic Acid; D008297:Male; D008845:Microinjections; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D015854:Up-Regulation; D051025:bcl-Associated Death Protein / Q000378:metabolism*
C494821:Bad protein, rat; D019253:Proto-Oncogene Proteins c-bcl-2; D051025:bcl-Associated Death Protein; D007608:Kainic Acid