Interaction of Cu+ with mitochondria.

The uptake of Cu+ by rat liver mitochondria is rapid and extensive. Respiration is stimulated by 10 microM Cu+ then inhibited and the inhibition could not be relieved with uncoupling agents. Collapse of the membrane potential is induced by 5-10 microM Cu+. These effects are partially inhibited by radical scavengers indicating the involvement of radical production in these events. Reduction of the GSH content and production of peroxidation products by higher amounts of Cu+ was also demonstrated. Swelling of non-respiring rat liver and heart mitochondria in sodium or lithium acetate was used to study effects of Cu+ on the Na+/H+ exchanger. Swelling is stimulated by 5-100 microM Cu+. In the presence of a radical scavenger the swelling is reduced. In sodium nitrate media diltiazem-sensitive stimulated swelling is observed. Amiloride was found to inhibit Cu(+)-induced efflux of Ca2+. At high concentrations of Cu+, a general increase in permeability was the dominant feature.