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

Abstract

The effect of electrical currents on oxidative phosphorylation of rat-brain mitochondria was studied using a variety of metallic conductors. Maximal inhibition of phosphorylation was obtained with silver-copper and Au electrodes, while with Pt and Ag electrodes inhibition was almost absent. When potassium ferricyanide replaced O2 as electron acceptor in the system, there was an inhibition of about 45% in the P/2 [Fe(CN)6]3- ratio regardless of the kind of conducting substance used in the construction of the electrode. Glutathione, sodium sulfide, and diethyldithiocarbamate, but not cysteine and many other reducing agents, were able to protect against inhibition of phosphorylation when O2 was the electron acceptor. A number of thiol-inhibiting agents were tested and were found, unlike electrical stimulation, primarily to depress oxidation, so that the P/O ratio was largely unchanged. Evidence for believing that the effect on phosphorylation is due to electrical currents and not to electrolytic artifacts is discussed.