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Contribution of nitric oxide, superoxide anion, and peroxynitrite to activation of mitochondrial apoptotic signaling in hippocampal CA3 subfield following experimental temporal lobe status epilepticus
Author(s) -
Chuang YaoChung,
Chen ShangDer,
Liou ChiaWei,
Lin TsuKung,
Chang WenNeng,
Chan Samuel H. H.,
Chang Alice Y. W.
Publication year - 2009
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1167.2008.01778.x
Subject(s) - peroxynitrite , superoxide , chemistry , cytochrome c , status epilepticus , nitric oxide , nitric oxide synthase , mitochondrial respiratory chain , hippocampal formation , peroxynitrous acid , superoxide dismutase , biochemistry , mitochondrion , oxidative stress , endocrinology , biology , neuroscience , epilepsy , enzyme , organic chemistry
Summary Purpose: One cellular consequence of status epilepticus is apoptosis in the hippocampal CA3 subfield. We evaluated the hypothesis that the repertoire of cellular events that underlie such elicited cell death entails mitochondrial dysfunction induced by an excessive production of nitric oxide synthase II (NOS II)‐derived NO, increased superoxide anion (O 2 − ) production, and peroxynitrite formation. Methods: In Sprague‐Dawley rats, kainic acid was microinjected unilaterally into the hippocampal CA3 subfield to induce bilateral seizure‐like electroencephalography (EEG) activity. The effects of pretreatments with various test agents on the induced O 2 − production, peroxynitrite formation, mitochondrial respiratory chain enzyme activities, cytochrome c /caspase‐3 signaling, and DNA fragmentation in bilateral CA3 subfields were examined. Results: Significantly and temporally correlated increase in O 2 − and peroxynitrite levels (3 to 24 h), depressed mitochondrial Complex I activity (3 h), enhanced translocation of cytochrome c to cytosol (day 1), and augmented activated caspase‐3 (day 7) and DNA fragmentation (day 7) were detected bilaterally in hippocampal CA3 subfields after the elicitation of sustained seizure. Pretreatment with microinjection into the bilateral hippocampal CA3 subfield of a water‐soluble formulation of coenzyme Q 10 ; a selective NOS II inhibitor, S ‐methylisothiourea; a superoxide dismutase mimetic, 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl; an active peroxynitrite decomposition catalyst, 5,10, 15,20‐tetrakis‐( N ‐methyl‐4‐pyridyl)‐ porphyrinato iron (III); or a peroxynitrite scavenger, L‐cysteine significantly blunted these cellular events. Discussion: Prolonged seizures prompted NO‐, O 2 − ‐, and peroxynitrite‐dependent reduction in mitochondrial respiratory enzyme Complex I activity, leading to cytochrome c /caspase‐3‐dependent apoptotic cell death in the hippocampal CA3 subfield after induction of experimental temporal lobe status epilepticus.