Glutamate transport, glutamine synthetase and phosphate-activated glutaminase in rat CNS white matter. A quantitative study.

摘要: Glutamatergic signal transduction occurs in CNS white matter, but quantitative data on glutamate uptake and metabolism are lacking. We report that the level of astrocytic transporter GLT rat fimbria corpus callosum was ∼ 35% parietal cortex; [3H]glutamate 24 43%, respectively, cortical value. In levels synaptic proteins, synapsin I synaptophysin were 15–20% those activities glutamine synthetase phosphate-activated glutaminase, enzymes involved transmitter glutamate, 11–25% values, aspartate alanine aminotransferases 50–70% values. The 5–6 nmol/mg tissue, half These suggest a certain capacity for glutamatergic neurotransmission. optic trigeminal nerves, < 10% uptake. Formation [14C]glutamate from [U-14C]glucose awake rats 30% nerve it 13%, illustrating extensive matter vivo. Glutamate transporters brain may be important both physiologically during energy failure when reversal contribute to excitotoxicity.