Recent studies have shown that glutamate excitotoxicity may be a component in the etiology of multiple sclerosis (MS). Glutamate transporters determine the levels of extracellular glutamate and are essential to prevent excitotoxicity. We have analyzed here the expression of the glutamate transporters EAAT1, EAAT2 and EAAT3 in control and in MS optic nerve samples. We observed an overall increas...

PURPOSE Vision is encoded at photoreceptor synapses by the number of released vesicles and size of the post-synaptic response. We hypothesized that elevating cytosolic glutamate could enhance quantal size by increasing glutamate in vesicles. METHODS We introduced glutamate (10-40 mM) into cone terminals through a patch pipette and recorded excitatory post-synaptic currents (EPSCs) from horizo...

In the nervous system, glutamate is an excitatory aminoacid which at higher concentrations has been implicated in a number of disorders. Glutamate is stored in presynaptic vesicles and is released by calcium-dependent exocytosis. After its action on ionotropic receptors (iGluR, related to ionic channels) or metabotropic receptors (mGluR, related to metabolic formation of second messengers), glu...

Glutamate, the most abundant excitatory transmitter in the brain can lead to neurotoxicity when not properly regulated. Excitotoxicity is a direct result of abnormal regulation of glutamate concentrations in the synapse, and is a common neurotoxic mediator associated with neurodegenerative disorders. It is well accepted that methamphetamine (METH), a potent central nervous stimulant with high a...

The regulation of glutamate dehydrogenase (EC 1.4.1.4), glutamine synthetase (EC 6.3.1.2), and glutamate synthase (EC 2.6.1.53) was examined for cultures of Salmonella typhimurium grown with various nitrogen and amino acid sources. In contrast to the regulatory pattern observed in Klebsiella aerogenes, the glutamate dehydrogenase levels of S. typhimurium do not decrease when glutamine synthetas...

Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. After release from glutamatergic nerve terminals, glial and neuronal glutamate transporters remove glutamate from the synaptic cleft to terminate synaptic transmission and to prevent neuronal damage by excessive glutamate receptor activation. In this issue of Molecular Pharmacology, Fontana et al. (p. 12...

Intrasynaptic [glutamate] must be kept low in order to maximize the signal-to-noise ratio after the release of transmitter glutamate. This is accomplished by rapid uptake of glutamate into astrocytes, which convert glutamate into glutamine. The latter then is released to neurons, which, via mitochondrial glutaminase, form the glutamate that is used for neurotransmission. This pattern of metabol...

The existence of glutamate receptors as important neurotransmitter receptors was not fully accepted until the 1980s. It is now generally agreed that glutamate is the major fast excitatory neurotransmitter in brain, and plays a major role in brain development, affecting neuronal migration, neuronal differentiation, axon genesis, and neuronal survival through its action on the glutamate receptors...