Extracellular glutamate concentrations are regulated by glial and neuronal transporter proteins. Four glutamate transporter subtypes have been identified in rat brain; GLAST and GLT-1 are primarily astrocytic, whereas EAAC1 and EAAT4 are neuronal. Using immunoblotting and immunohistochemistry with subtype-specific antipeptide antibodies, we examined the protein expression and regional and cellu...

Glutamate transport in early, undifferentiated oligodendrocytic precursors has not been characterized thus far. Here we show that human oligodendroglioma Hs683 cells are not endowed with EAAT-dependent anionic amino acid transport. However, in these cells, but not in U373 human glioblastoma cells, valproic acid (VPA), an inhibitor of histone deacetylases, markedly induces SLC1A1 mRNA, which enc...

Photoreceptor ribbon synapses tonically release glutamate. To ensure efficient signal transmission and prevent glutamate toxicity, a highly efficient glutamate removal system provided by members of the SLC1 gene family is required. By using a combination of biophysical and in vivo studies, we elucidate the role of excitatory amino acid transporter 2 (EAAT2) proteins in synaptic glutamate homeos...

The D-isomer of aspartate is efficiently transported by high-affinity Na(+)/K(+)-dependent glutamate transporters and is an effective ligand of N-methyl-d-aspartate (NMDA) receptors. To facilitate analysis of the regulation of these proteins in their native membranes, we synthesized a photolabile analogue of D-aspartate, 4-methoxy-7-nitroindolinyl-D-aspartate (MNI-D-aspartate). This compound wa...

In complex neural circuits of the brain, massive information is processed with neuronal communication through synaptic transmissions. It is thus fundamental to delineate information flows encoded by various kinds of transmissions. Here, we show that glutamate signals from two distinct sensory neurons bidirectionally affect the same postsynaptic interneuron, thereby producing the opposite behavi...

PurposeOur purpose was to better understand the pathogenesis of seizures associated with angiocentric glioma. Angiocentric glioma is an indolent and rare low-grade Its typical clinical presentation epileptic seizures. The tumor-associated poorly understood. Among possible pathomechanisms, increased neurotoxic concentrations glutamate has been proposed. Glutamate transporters, pyruvate carboxyla...

Recently, a new model for glutamate uptake by glutamate transporters was proposed based on crystal structures of the bacterial glutamate transporter homolog Glt(Ph). It was proposed that hairpin two (HP2) functions as the extracellular gate and that Na(+) and glutamate binding closes HP2, thereby allowing for the translocation of the glutamate binding pocket across the membrane. However, the co...

Vesicular glutamate transporter is present in neuronal synaptic vesicles and endocrine synaptic-like microvesicles and is responsible for vesicular storage of L-glutamate. A brain-specific Na(+)-dependent inorganic phosphate transporter (BNPI) functions as a vesicular glutamate transporter in synaptic vesicles, and the expression of this BNPI defines the glutamatergic phenotype in the central n...

The behavior of a Cl- channel associated with a glutamate transporter was studied using intracellular and patch recording techniques in Xenopus oocytes injected with human EAAT1 cRNA. Channels could be activated by application of glutamate to either face of excised membrane patches. The channel exhibited strong selectivity for amphipathic anions and had a minimum pore diameter of approximately ...

Glutamate excitotoxicity contributes to oligodendrocyte and tissue damage in multiple sclerosis (MS). Here, we have examined if glutamate homeostasis is altered in plasma from MS patients. We initially observed that plasma glutamate levels are elevated in MS patients as compared to control subjects. In addition, we have studied the presence of a polymorphism sited in the promoter of the glutama...