title: Changes in calcium-dependent membrane permeability properties in mitochondria of livers from arthritic rats.
abstract: The involvement of the mitochondrial permeability transition pore (PTP) in the responses of mitochondria from adjuvant-induced arthritic rats to Ca(2+) addition was investigated. The respiratory activity, the Ca(2+)-induced osmotic swelling and the electrophoretic (45)Ca(2+) uptake were evaluated in the absence and in the presence of cyclosporin A (CsA), a well-known inhibitor of the mitochondrial PTP. The Ca(2+)-induced mitochondrial permeability transition (MPT) process occurred in mitochondria from arthritic rats even in the presence of a low Ca(2+) concentration. Whereas in the normal condition, the Ca(2+)-induced uncoupling of oxidative phosphorylation and osmotic swelling was observed in the presence of 10 or 20 microM Ca(2+) concentration, in the arthritic condition, these events occurred at 1.0 microM concentration. In addition, mitochondria from arthritic rats presented an impaired ability to accumulate (45)Ca(2+). All these effects were completely prevented by the administration of CsA. The results of the present study suggest that the higher sensitivity of mitochondria from arthritic rats to Ca(2+)-induced MPT may be an important factor in the pathogenesis of the arthritis disease.
authors.affiliation: Laboratory of Biological Oxidations, Department of Biochemistry, University of Maringá, Maringá, Brazil.
authors.forename: Pamelli Maria de Souza
authors.initials: PM
authors.lastname: Silva
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tanabe
authors.forename: Aparecida Pinto Munhos
authors.initials: AP
authors.lastname: Hermoso
authors.forename: Ciomar A
authors.initials: CA
authors.lastname: Bersani-Amado
authors.forename: Adelar
authors.initials: A
authors.lastname: Bracht
authors.forename: Emy L
authors.initials: EL
authors.lastname: Ishii-Iwamoto
authors.forename: Clairce Luzia
authors.initials: CL
authors.lastname: Salgueiro-Pagadigorria
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D016572:Cyclosporine / Q000494:pharmacology; D007425:Intracellular Membranes / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D008933:Mitochondrial Swelling; D010100:Oxygen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D016572:Cyclosporine; D010100:Oxygen; D002118:Calcium