Mersalyl prevents the Tl-induced permeability transition pore opening in the inner membrane of Ca-loaded rat liver mitochondria.

It was earlier shown that the calcium load of rat liver mitochondria in medium containing TlNO and KNO resulted in the Tl-induced mitochondrial permeability transition pore (MPTP) opening in the inner membrane. This opening was accompanied by an increase in swelling and membrane potential dissipation and a decrease in state 3, state 4, and 2,4-dinitrophenol-uncoupled respiration. This respiratory decrease was markedly leveled by mersalyl (MSL), the phosphate symporter (PiC) inhibitor which poorly stimulated the calcium-induced swelling, but further increased the potential dissipation. All of these effects of Ca and MSL were visibly reduced in the presence of the MPTP inhibitors (ADP, N-ethylmaleimide, and cyclosporine A). High MSL concentrations attenuated the ability of ADP to inhibit the MPTP. Our data suggest that the PiC can participate in the Tl-induced MPTP opening in the inner membrane of Ca-loaded rat liver mitochondria.