Glutamate activity

Other systems also interact with glutamate. Activation of L-type voltagegated calcium channels (VGCC) occurs with NMDA receptor activation. Lamotrigine blocks several ion channels, including P- and N-type VGCC channels, an action that blocks the euphoric effects of ketamine and reduces dysphoric and cognitive effects (Hundt et al. 1998). Other modulatory sites,... 

Nowak L, Bregestovski P, Ascher P, Herbet A, Prochiantz A. Magnesium gates glutamate-activated channels in mouse central neurones. Nature 1984 307 462-465. 

During ischaemia, NOS is activated by calcium influx or by cytokines like tumour necrosis factor (TNF) or by lipopolysaccharide (LPS) and NO is produced in excess. It has been proposed that the excitotoxic effect of glutamate, which contributes to ischaemia-induced neuronal damage, is mediated by increased production of NO via a chain of events that includes increases in intracellular calcium (via glutamate activation of NMDA receptors), calcium activation of NOS, production of NO and peroxynitrite, and induction of lipid peroxidation. In fact, N-nitro-L-atginine, a selective inhibitor of NOS, has been shown to prevent glutamate-induced neurotoxicity in cortical cell cultures (Dawson rf /., 1991). 

Deficiency of GABA or excessive glutamate activity causes dysregulation of neurotransmitters (e.g, increased DA and NE activity). 

Agents that increase GABA activity or decrease glutamate activity are used for the treatment of mania and for mood stabilization (eg, benzodiazepines, lamotrigine, lithiurn, or valproic acid). 

Narahashi T, Zhao X, Ikeda T, Salgado VL, Yeh JZ (2010) Glutamate-activated chloride channels unique lipronil targets present in insects but not in mammals. Pestic Biochem Physiol 97 149-152... 

There is now evidence that the mammalian central nervous system contains several dozen neurotransmitters such as acetylcholine, noradrenaline, dopamine and 5-hydroxytryptamine (5-HT), together with many more co-transmitters, which are mainly small peptides such as met-enkephalin and neuromodulators such as the prostaglandins. It is well established that any one nerve cell may be influenced by more than one of these transmitters at any time. If, for example, the inhibitory amino acids (GABA or glycine) activate a cell membrane then the activity of the membrane will be depressed, whereas if the excitatory amino acid glutamate activates the nerve membrane, activity will be increased. The final response of the nerve cell that receives all this information will thus depend on the balance between the various stimuli that impinge upon it. 

Glutamate activates the N-methyl-D-aspartate (NMDA) receptor. Glutamate is involved in perception of pain, sensory input, and memory. PCP and dextromethorphan block this receptor. 

Glutamate activation requires binding of glycine at a specific binding site. 

Cold Lability of Carbamyl-P Synthetase. The acetyl glutamate-activated enzyme is less stable at low temperatures than the nonacti-vated enzyme preparations (35). The frog enzyme is stable over a wide temperature range. In the presence of acetyl glutamate, it retains its stability if stored above 10° and as high as 45°, but it is inactivated atO to 5°. This is one of four cases known to us, of enzymatically active... 

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