KINETICS OF 2-OXOGLUTARATE UPTAKE BY SYNAPTOSOMES FROM BOVINE AND RAT RETINA AND CEREBRAL-CORTEX AND REGULATION BY GLUTAMATE AND GLUTAMINE

2-Oxoglutarate (2-OG) is a metabolic precursor of glutamate and may be utilized to replenish the neurotransmitter pool. 2-OG is rapidly transported into neurons by a high-affinity carrier that is particularly prevalent in glutamatergic terminals. Here we report the kinetics of [U-C-14]2-OG uptake by crude synaptosomal preparations from bovine and rat retina and brain, and the modulatory effects of glutamate and glutamine. In all four tissues, 2-OG uptake was mediated by a high-affinity system (K-t approximate to 1 mu M) that was subject to negative feedback control by glutamate and biphasic modulation by glutamine (another precursor of neurotransmitter glutamate).