TY - JOUR. T1 - Protective effect of excitatory amino acids on cold-restraint stress-induced gastric ulcers in mice. T2 - Role of cyclic nucleotides. AU - Chen, Sheng Hsuan. AU - Lei, Hsiao Ling. AU - Huang, Lih Ron. AU - Tsai, Li Hsueh. PY - 2001. Y1 - 2001. N2 - Previous studies have shown that excitatory amino acids (EAAs) and their receptors may play important roles in the mammalian enteric system. In this study, we investigated whether EEAs, including L-glutamate (L-Glu) and subtypes N-methyl-D-aspartate (NMDA), kainic acid (KA), and quisqualic acid (QA), reduce cyclic AMP (cAMP) levels and play a role in protecting gastric lesions in cold-restraint stress (CRS) mice. First, we found that dose-dependent administration of four selected EAAs significantly attenuated the increase of cAMP content and exhibited a protective effect on the development of gastric lesions induced by CRS. Second, CRS treatment exhibited a decrease of cGMP content and an increase of cAMP content with marked ...

The effects of excitatory amino acids on 22Na efflux rate in rat hippocampal slices were determined at various postnatal days and following removal of a major afferent system. Two weeks after a unilateral hippocampal aspiration, the 22Na efflux induc

1MM6: Mechanism of activation and selectivity in a ligand-gated ion channel: Structural and functional studies of GluR2 and quisqualate

1MM7: Mechanism of Activation and Selectivity in a Ligand-Gated Ion Channel: Structural and Functional Studies of GluR2 and Quisqualate

Metabotropic glutamate receptor (mGluR) modulation of voltage-gated Ca2+ channels was examined in isolated deep layer frontoparietal cortical neurons under conditions designed to isolate calcium- independent modulatory pathways. Trans-1-aminocyclopentane-1,3- dicarboxylate (t-ACPD), a nonspecific mGluR agonist, produced rapid and reversible inhibition of Ca2+ channels. This effect was mimicked by agonists for group I and group II, but not group III, mGluRs. Effects of group I and II agonists often were observed in the same neurons, but separate subgroups of neurons were unresponsive to the group I agonist quisqualate or the group II agonist 2-(2,3-dicarboxycyclopropyl) glycine (DCG-IV). Inhibition by quisqualate and DCG-IV was nonocclusive in neurons responding to both agonists. These agonists thus appear to act on different mGluRs. The mGluR antagonist alpha-methyl-4- carboxylphenylglycine attenuated inhibition by t-ACPD, quisqualate, and DCG-IV. Inhibition by quisqualate and DCG-IV was ...

Glutamate activates a number of different receptor-channel complexes, each of which may contribute to generation of excitatory postsynaptic potentials in the mammalian central nervous system. The rapid application of the selective glutamate agonist, quisqualate, activates a large rapidly inactivating current (3 to 8 milliseconds), which is mediated by a neuronal ionic channel with high unitary conductance (35 picosiemens). The current through this channel shows pharmacologic characteristics similar to those observed for the fast excitatory postsynaptic current (EPSC); it reverses near 0 millivolts and shows no significant voltage dependence. The amplitude of the current through this channel is many times larger than that through the other non-NMDA (N-methyl-D-aspartate) channels. These results suggest that this high-conductance quisqualate-activated channel may mediate the fast EPSC in the mammalian central nervous system. ...

Selective stimulation of excitatory amino acid receptor subtypes and the survival of cerebellar granule cells in culture: effect of kainic acid. ...

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Ion channels coupled to NMDA, kainate and AMPA receptors are the target of pharmacological regulation by a variety of drugs and ions. While these channels are all nonselectively permeated by Na+ and K+ ions, the NMDA receptor-channel complex contains a number of pharmacological sites distinct from t …

The changes in excitatory amino acid receptor ligand binding induced by transient cerebral ischemia were studied in the rat hippocampal subfields. Ten minutes of ischemia was induced by common carotid artery occlusion combined with hypotension, and the animals were allowed variable periods of recovery ranging from 1 day to 4 weeks. The binding of 3H-AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) to quisqualate receptors, 3H-kainic acid (KA) to kainate receptors, and 3H-glutamate to N-methyl-D-aspartate (NMDA) receptors as determined by quantitative autoradiography. One week following ischemia the CA1 region of the hippocampus displayed a severe (90%) dendrosomatic lesion with preservation of presynaptic terminals. This was associated with a 60% decrease in AMPA binding and a 25% decrease in glutamate binding to NMDA receptors. At 4 weeks postischemia, both AMPA and NMDA sites were greatly reduced. Although the dentate gyrus granule cells are resistant to an ischemic insult of ...

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10561-01-0 - UQDJZHBCEVUVNR-OWBHPGMISA-N - 3,5-Pyrazolidinedione, 4-(3-chloro-2-butenyl)-1,2-diphenyl- - Similar structures search, synonyms, formulas, resource links, and other chemical information.

TY - JOUR. T1 - Noncompetitive excitatory amino acid receptor antagonists. AU - Lodge, David. AU - Johnson, Kenneth M.. PY - 1990. Y1 - 1990. N2 - In the first article in this series, Watkins, Krogsgaard-Larsen and Honoré outlined the structure-activity requirements at the receptor sites for excitatory amino acids in the mammalian CNS. The postsynaptic depolarizing actions of glutamate are thought to be mediated by NMDA, AMPA and kainate receptors. Here David Lodge and Kenneth M. Johnson review some of the recent developments in the pharmacology of other means by which the function of these receptors may be modulated. Divalent cations, phencyclidine-like drugs, glycine analogues and polyamines all modulate NMDA receptors whereas barbiturates and some arthropod toxins reduce channel responses to non-NMDA receptor agonists. Modes of action and implications for physiology and pathophysiology are discussed.. AB - In the first article in this series, Watkins, Krogsgaard-Larsen and Honoré outlined ...

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2S-(2 alpha,3 beta,4 beta))-2-Carboxy-4-(1-methylethenyl)-3-pyrrolidineacetic acid. Ascaricide obtained from the red alga Digenea simplex. It is a potent excitatory amino acid agonist at some types of excitatory amino acid receptors and has been used to discriminate among receptor types. Like many excitatory amino acid agonists it can cause neurotoxicity and has been used experimentally for that purpose ...

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