Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/194057
Type: Artigo de periódico
Title: Ca2+-independent Permeabilization Of The Inner Mitochondrial Membrane By Peroxynitrite Is Mediated By Membrane Protein Thiol Cross-linking And Lipid Peroxidation.
Author: Gadelha, F R
Thomson, L
Fagian, M M
Costa, A D
Radi, R
Vercesi, A E
Abstract: Peroxynitrite anion, the reaction product of superoxide and nitric oxide, is a potent biological oxidant, which inactivates mammalian heart mitochondrial NADH-coenzyme Q reductase (complex I), succinate dehydrogenase (complex II), and ATPase, without affecting cytochrome c oxidase (complex IV). In this paper, we evaluated the effect of peroxynitrite on mitochondrial membrane integrity and permeability under low calcium concentration. Phosphate buffer was used in most of our experiments since Hepes, Tris, mannitol, and sucrose were found to inhibit the oxidative chemistry of peroxynitrite. Peroxynitrite (0.1-1.0 mM) caused a dose-dependent decrease in the ability of mitochondria to build up a membrane potential when N,N,N',N'-tetramethyl-p-phenylenediamine/ascorbate were used as substrate. Elimination of the membrane potential was accompanied by penetration of the osmotic support (KCl/NaCl) into the matrix as judged by the parallel occurrence of mitochondrial swelling. This swelling was partially inhibited by dithiothreitol (DTT) or butylated hydroxytoluene (BHT) and was insensitive to ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, ADP, and cyclosporin A. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of solubilized membrane proteins indicated that alterations in membrane permeability were associated with the production of protein aggregates due to membrane protein thiol cross-linking. The protective effect of DTT on both mitochondrial swelling and protein polymerization suggests the involvement of disulfide bonds in the membrane permeabilization process. In addition, the increase in thiobarbituric acid-reactive substances and the partial inhibitory effect of BHT indicate the occurrence of lipid peroxidation. These results support the idea that under our experimental conditions peroxynitrite causes mitochondrial structural and functional alterations by Ca2+-independent mechanisms through lipid peroxidation and protein sulfhydryl oxidation.
Subject: Animals
Calcium
Cross-linking Reagents
Female
Intracellular Membranes
Lipid Peroxidation
Membrane Potentials
Mitochondria, Liver
Nitrates
Oxidants
Permeability
Rats
Rats, Wistar
Sulfhydryl Compounds
Thiobarbituric Acid Reactive Substances
Rights: fechado
Identifier DOI: 10.1006/abbi.1997.0259
Address: http://www.ncbi.nlm.nih.gov/pubmed/9308896
Date Issue: 1997
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File SizeFormat 
pmed_9308896.pdf240.26 kBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.