Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/194078
Type: Artigo de periódico
Title: The Permeability Transition Pore Opening In Intact Mitochondria And Submitochondrial Particles.
Author: de Macedo, D V
da Costa, C
Pereira-Da-Silva, L
Abstract: The mitochondrial permeability transition was investigated under both oxidative and nonoxidative conditions. It was observed that dithiothreitol (DTT) was able to inhibit the permeability transition only when an oxidant, t-butylhydroperoxide, was used. Although cyclosporin A (CsA) showed also a partial protective effect under these conditions, it progressively lost its ability as the oxidant concentration was increased. Indeed, CsA and ADP were very effective under nonoxidative conditions where Ca2+ and Pi were used to induce the permeability transition, and no effect of DTT was observed. These results suggest that the Ca(2+)-dependent permeability transition pore opening is not directly dependent of dithiol oxidation. It was also shown here that CsA, independent of the presence of ADP, was able to restore the mitochondrial membrane electrical potential (delta psi) after the Ca(2+)-induced collapse. Moreover, carboxyatractyloside (CAT) did not prevent the effect of CsA, even when previously added, although it completely abolished the protective effect of ADP, indicating the participation of the ADP/ATP carrier on this process. The data with submitochondrial particles, besides providing further support to the existence of two distinct binding sites for Ca2+ in the mitochondrial inner membrane, with opposite effects on the pore opening probability, demonstrated, for the first time, that very low Ca2+ concentrations induced the permeability transition pore (PTP) opening in submitochondrial particles, an event fully prevented by CsA. The existence of such CsA-sensitive Ca(2+)-induced pore in submitochondrial particles also suggests that matrix cyclophilin is probably not the mediator of this process.
Subject: Adenosine Diphosphate
Animals
Calcium
Cyclosporine
Dithiothreitol
Female
In Vitro Techniques
Ion Transport
Membrane Potentials
Mitochondria, Liver
Oxidants
Permeability
Peroxides
Rats
Rats, Wistar
Submitochondrial Particles
Tert-butylhydroperoxide
Rights: fechado
Identifier DOI: 
Address: http://www.ncbi.nlm.nih.gov/pubmed/9418011
Date Issue: 1997
Appears in Collections:Unicamp - Artigos e Outros Documentos

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