Methylmercury induces the opening of the permeability transition pore in rat liver mitochondria

Interactions of methylmercury (CH3HgC]) with non-energized mitochondria from rat liver (non-respiring mitochondria) have been investigated in this paper. It has been shown that CH3HgCl induces swelling in mitochondria suspended in a sucrose medium. Swelling has also been induced by detergent compounds and by phenylarsine, a chemical compound which induces opening of the permeant transition pore (MTP). Opening of the MTP is inhibited by means of cyclosporine A. Results indicate that the swelling induced by CH3HgCl, as in the case of phenylarsine, is inhibited by cyclosporine A and Mg2+, while swelling induced by detergent compounds is not cyclosporine sensitive. This comparison suggests that CH3HgCl induces opening of a permeability transition pore (MTP). Since the opening of an MTP induces cell death, this interaction with MTP could be one of the causes of toxicity of CH3HgCl. (C) 2002 Elsevier Science Inc. All rights reserved.