The excitatory amino acid, glutamate, and several of its agonists are known to produce locomotory activity in the lamprey (Brodin et al. 1985), rat (Kudo and Yamada, 1987) and the embryos and larvae of amphibians (Dale and Roberts, 1984; McClellan and Farel, 1985). It is hypothesized that glutamate acts as a neurotransmitter in the neuronal pathway that generates locomotion in these systems. In...

In this review, we briefly describe glutamate (Glu) metabolism and its specific transports and receptors in the central nervous system (CNS). Thereafter, we focus on excitatory amino acid transporters, cystine/glutamate antiporters (system xc-) and vesicular glutamate transporters, specifically addressing their location and roles in CNS and the molecular mechanisms underlying the regulation of ...

Alanyl-alpha-glutamate transport has been studied in Lactococcus lactis ML3 cells and in membrane vesicles fused with liposomes containing beefheart cytochrome c oxidase as a proton-motive-force-generating system. The uptake of Ala-Glu observed in de-energized cells can be stimulated 26-fold upon addition of lactose. No intracellular dipeptide pool could be detected in intact cells. In fused me...

Glutamate transport by the neuronal excitatory amino acid carrier (EAAC1) is accompanied by the coupled movement of one proton across the membrane. We have demonstrated previously that the cotransported proton binds to the carrier in the absence of glutamate and, thus, modulates the EAAC1 affinity for glutamate. Here, we used site-directed mutagenesis together with a rapid kinetic technique tha...

This review focuses on the role of acute pH changes in the regulation of Gln/Glu metabolism in the kidney, liver, and brain. Alterations of proton concentration ([H+]) profoundly affect flux through phosphate-dependent glutaminase (PDG) or glutamate dehydrogenase (GDH), the primary enzymes responsible for mitochondrial metabolism of glutamine and glutamate, respectively. In the kidney, acute ac...

The effects of acute rise in corticosterone concentration upon the levels of hippocampal glutamate (Glu) are well described. Much less is known about the effect of chronic elevation of glucocorticoids on hippocampal glutamate. This is an important question, given the role of glutamate in the neurodegenerative and cognitive effects of chronic stressors. To this end, we have compared the effects ...

Neither expression nor functionality is clear in peripheral tissues with the molecular machineries required for excitatory neurotransmitter signaling by L-glutamate (Glu) in the central nervous system, while a recent study has shown that several Glu receptors are functionally expressed in the rat testis. This fact prompted us to explore the possible functional expression in the rat testis of th...

Recently, decreased glutamate (Glu) and reduced glutathione (GSH) levels were reported in the quadriceps femoris of patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to investigate whether Glu and GSH levels are also modified in the diaphragm of these patients. Nine male COPD patients (forced expiratory volume in one second (FEV1) range 28-68% of the p...

To understand the elementary unit of synaptic communication between CNS neurons, one must know what causes the variability of quantal postsynaptic currents and whether unitary packets of transmitter saturate postsynaptic receptors. We studied single excitatory synapses between hippocampal neurons in culture. Focal glutamate application at individual postsynaptic sites evoked currents (I(glu)) w...

Introduction Licorice could exhibit beneficial effect in the management of insomnia by regulating key modulators such as GABA and serotonin, we therefore aimed to study potentail hypnotic licorice extract, glycyrrhizin (GCZ), on underlying mechanisms. Material methods Mice were randomly grouped a Control group, GCZ (low) (high) group DZP with 8 mice each group. Sleep latency, sleep duration loc...