We investigated the cellular mechanisms underlying the Ca(2+)-dependent release of glutamate from cultured astrocytes isolated from rat hippocampus. Using Ca(2+) imaging and electrophysiological techniques, we analyzed the effects of disrupting astrocytic vesicle proteins on the ability of astrocytes to release glutamate and to cause neuronal electrophysiological responses, i.e., a slow inward ...

Reducing the enduring vulnerability to relapse is a therapeutic goal in treating drug addiction. Studies with animal models of drug addiction show a marked increase in extrasynaptic glutamate in the core subcompartment of the nucleus accumbens (NAcore) during reinstated drug seeking. However, the synaptic mechanisms linking drug-induced changes in extrasynaptic glutamate to relapse are poorly u...

In the cochlea, afferent transmission between inner hair cells and auditory neurons is mediated by glutamate receptors. Glutamate transporters located near the synapse and in spiral ganglion neurons are thought to maintain low synaptic levels of glutamate. We analyzed three glutamate transporter blockers for their ability to alter the effects of glutamate, exogenously applied to the synapse via...

BACKGROUND Previous study has demonstrated the efficacy of hemodialysis in reducing blood glutamate levels. The purpose of the present study is to investigate whether peritoneal dialysis (PD) may be effective in lowering blood glutamate levels, which may serve as a potential tool for improving neurological function after brain injury. METHODS Two liters of dialysis solution were infused over ...

Excess glutamate in brain fluids characterizes acute brain insults such as traumatic brain injury and stroke. Its removal could prevent the glutamate excitotoxicity that causes long-lasting neurological deficits. As blood glutamate scavenging has been demonstrated to increase the efflux of excess glutamate from brain into blood, we tested the prediction that oxaloacetate-mediated blood glutamat...

Hyperexcitability of the hippocampus is a commonly observed phenomenon in the years preceding a diagnosis of Alzheimer's disease (AD). Our previous work suggests a dysregulation in glutamate neurotransmission may mediate this hyperexcitability, and glutamate dysregulation correlates with cognitive deficits in the rTg(TauP301L)4510 mouse model of AD. To determine whether improving glutamate regu...

Welbourne, Tomas, and Itzhak Nissim. Regulation of mitochondrial glutamine/glutamate metabolism by glutamate transport: studies with 15N. Am J Physiol Cell Physiol 280: C1151–C1159, 2001.—We focused on the role of plasma membrane glutamate uptake in modulating the intracellular glutaminase (GA) and glutamate dehydrogenase (GDH) flux and in determining the fate of the intracellular glutamate in ...

The regulation of extracellular glutamate in the nucleus accumbens by group II metabotropic glutamate receptors (mGluR2/3) was examined in vivo. Stimulation of mGluR2/3 with 2R,4R-4-aminopyrrolidine-2,4-dicarboxylate (APDC) or N-acetylaspartylglutamate reduced extracellular glutamate levels. Conversely, blockade of mGluR2/3 by LY143495 or (RS)-1-amino-5-phosphonoindan-1-carboxylic acid (APICA) ...

PURPOSE To characterize glutamate uptake in the human retinal pigment epithelial (HRPE) cell line 165 and to determine the feasibility of using this cell line as an experimental model for glutamate transport studies. METHODS Confluent monolayers of the HRPE cells cultured in 35-mm petri dishes were used to study glutamate uptake with regard to its ion dependence, substrate specificity, and ki...

Gamma aminobutyrate (GABA) is a non-protein amino acid that is thought to play an important role in the modulation of the central response to stress. Mechanisms by which GABA may facilitate these responses to stress are metabolic and/or mechanical disruptions. Environmental stresses increase GABA accumulation through cytosolic acidification, induce an acidic pH-dependent activation of glutamate...