Glutamate metabolism and transport in rat brain mitochondria

1. The metabolism and transport of glutamate and glutamine in rat brain mitochondria of non-synaptic origin has been studied in various states. 2. These mitochondria exhibited glutamate uptake and swelling in iso-osmotic ammonium glutamate, both of which were inhibited by N-ethylmaleimide. 3. The oxidation of glutamate was inhibited by 20% by avenaciolide, but glutamine oxidation was not affected. 4. These mitochondria, when metabolizing glutamine, allowed glutamate, but very little aspartate, to efflux at considerable rates. 5. These results suggests that brain mitochondria of non-synaptic origin possess in addition to a relatively rapid glutamate-aspartate translocase, a relatively slow aspartate-independent glutamate-OH-translocase (cf. liver mitochondria).