Inhibition of oxidative phosphorylation in brain mitochondria by electrical currents and the effect of chelating agents and other substances.

In a previous study involving the inhibition of oxidative phosphorylation in brain mitochondria by electrical currents, it was observed that the effect varied with the kind of conductive substance used in the construction of the electrode (Abood, 1954). Electrodes constructed of either gold or an alloy of silver and gold were most effective, while silver and platinum electrodes were least effective. Although less polarization occurred with the former pair, it was not possible to account for the variation with the electrodes solely on the basis of electrolytic polarization. Another phenomenon known to depend on the nature of the conductive metal is electrolytic oxidation, whereby hydroxyl and other related oxidizing radicals are formed (Glasstone & Hickling, 1939). Since such oxidizing radicals, not to mention heavy-metal ions formed near the surface ofthe electrode, could oxidize thiol enzymes (see Barron, 1951 for review), it was necessary to determine to what extent electrolytic oxidations may have contributed to the inhibition of phosphorylation by electrical currents. In the course of such experiments it has been found that, although in the case of some metals, particularly the alloys of silver and copper, electrolytic oxidation does occur to some extent, the metabolic effects are by and large due to the electrical currents themselves. It has been found that, independently of any effect on heavy metals, glutathione and certain other chelating and reducing substances will protect against the inhibition ofphosphorylation by electrical currents.