EFFECTS OF EXTRACELLULAR ZINC ION ON THE RATE OF OXYGEN CONSUMPTION OF RAT BRAIN MITOCHONDRIA

The inhibitory effect of extracellular zinc ion on the rate of oxygen consumption of rat brain mitochondria pre-incubated in 1.0 mM Ca2+EDTA were determined. There was a significant increase [P<0.01] in the rate of oxygen consumption in the rat brain mitochondria pre-incubated in 1.0 mM Ca²⁺EDTA in a succinate initiated reaction. The reverse was the case when the concentration of Ca2⁺EDTA was increased to 10 mM. A 20μM zinc-aspartate was found to have no inhibitory effect on the rate of oxygen consumption of the brain mitochondria pre-incubated with 1.0 mM Ca²⁺EDTA when compared with the control that lacked 1.0 mM Ca²⁺EDTA, however there was a significant decrease [P<0.01] in the rate of oxygen consumption of the rat brain mitochondria in the control experiment.