Na+-dependent, high-affinity glutamate transporters in the central nervous system are generally credited with regulating extracellular levels of L-glutamate and maintaining concentrations below those that would induce excitotoxic injury. Under pathological conditions, however, it has been suggested that these same transporters may contribute to excitotoxic injury by serving as sites of efflux f...

The PEB1a protein of the gastrointestinal pathogen Campylobacter jejuni mediates interactions with epithelial cells and is an important factor in host colonization. Cell fractionation and immunoblotting showed that PEB1a is most abundant in the periplasm of C. jejuni, and is detectable in the culture supernatant but not in the inner or outer membrane. The protein is homologous with periplasmic-...

INTRODUCTION The optimal blood glucose target following severe traumatic brain injury (TBI) must be defined. Cerebral microdialysis was used to investigate the influence of arterial blood and brain glucose on cerebral glucose, lactate, pyruvate, glutamate, and calculated indices of downstream metabolism. METHODS In twenty TBI patients, microdialysis catheters inserted in the edematous frontal...

Extracellular application of glutamate elicited cytoplasmic Ca2+ transients in freshly dissociated rat neurones of the dorsal cochlear nucleus (DCN) (identified as pyramidal cells) with half-maximal concentration of 513 micromol/l while saturating doses (5 mmol/l) of this neurotransmitter caused transients of 46.1 +/- 3.0 nmol/l on an average. The genesis of these glutamate-evoked Ca2+ transien...

L-Glutamate elicits an inwardly rectifying current at hyperpolarized potentials in isolated retinal cones of the tiger salamander, as measured under whole-cell patch clamp. Evidence presented in this article supports the notion that cones possess a high-affinity glutamate transporter. This glutamate-elicited current shows no desensitization over a period of several minutes, and has an affinity ...

In islets of Langerhans, L-glutamate is stored in glucagon-containing secretory granules of -cells and cosecreted with glucagon under low-glucose conditions. The L-glutamate triggers secretion of -aminobutyric acid (GABA) from -cells, which in turn inhibits glucagon secretion from -cells through the GABAA receptor. In the present study, we tested the working hypothesis that L-glutamate function...

High aminotransferase activities catalyzing the reactions between L-glutamate and L-glutamine and the aliphatic ketomonocarboxylic acids 2-ketoisocaproate, 2-ketocaproate, and 2-ketoisovalerate were observed in pancreatic B-cell mitochondria. While maximal rates of transamination with L-glutamate were observed in the presence of micromolar concentrations of keto acid, maximal rates of transamin...

The effects of L-glutamate and its analogues were studied in voltage-clamped motoneurons of the lobster cardiac ganglion. These excitatory amino acids caused a dose-dependent increase in membrane conductance and an inward current at the resting membrane potential. The EC50 for L-glutamate was 150 mumol 1(-1). The rank order of potencies of the various agonists was quisqualate greater than L-glu...

Burst firing of dopaminergic neurons in ventral tegmental area (VTA) induces a large transient increase in synaptic dopamine (DA) release and thus is considered the reward-related signal. But the mechanisms of burst generation of dopaminergic neuron still remain unclear. This experiment investigated the burst firing of VTA dopaminergic neurons in rat midbrain slices perfused with carbachol and ...

The dependence of glutamate uptake on ATP-generated proton electrochemical potential was studied in a highly purified preparation of synaptic vesicles from rat brain. At low chloride concentration (4 mM), the proton pump present in synaptic vesicles generated a large membrane potential (inside-positive), associated with only minor acidification. Under these conditions, the rate of L-[3H]glutama...