Search results for " Glutamate"

Modelling the spatial and temporal constrains of the GABAergic influence on neuronal excitability

2021

GABA (γ-amino butyric acid) is an inhibitory neurotransmitter in the adult brain that can mediate depolarizing responses during development or after neuropathological insults. Under which conditions GABAergic membrane depolarizations are sufficient to impose excitatory effects is hard to predict, as shunting inhibition and GABAergic effects on spatiotemporal filtering of excitatory inputs must be considered. To evaluate at which reversal potential a net excitatory effect was imposed by GABA (EGABAThr), we performed a detailed in-silico study using simple neuronal topologies and distinct spatiotemporal relations between GABAergic and glutamatergic inputs. These simulations revealed for GABAe…

Novel modes of rhythmic burst firing at cognitively-relevant frequencies in thalamocortical neurons.

2008

It is now widely accepted that certain types of cognitive functions are intimately related to synchronized neuronal oscillations at both low (alpha/theta) (4-7/8-13 Hz) and high (beta/gamma) (18-35/30-70 Hz) frequencies. The thalamus is a key participant in many of these oscillations, yet the cellular mechanisms by which this participation occurs are poorly understood. Here we describe how, under appropriate conditions, thalamocortical (TC) neurons from different nuclei can exhibit a wide array of largely unrecognised intrinsic oscillatory activities at a range of cognitively-relevant frequencies. For example, both metabotropic glutamate receptor (mGluR) and muscarinic Ach receptor (mAchR) …

Neuroactive compounds produced by bacteria from the marine sponge Halichondria panicea: activation of the neuronal NMDA receptor

1998

Abstract Previous studies revealed that the marine sponge Halichondria panicea habors symbiotic- and commensalic bacteria ( Althoff et al., 1998 . Marine Biol. 130, 529–536). In the present study the hypothesis was tested whether some of those bacteria synthesize neuroactive compounds. For the first time the effect of bacterial bioactive compounds on the neuronal ionotropic glutamate receptors [iGluR], subtype N -methyl- d -aspartate (NMDA) receptor, was checked. In cortical neurons from rats as cell system the supernatant of two bacterial cultures isolated from H. panicea proved to agonize the NMDA receptor. The response of the NMDA receptor to the bioactive compounds was determined by mea…

Role of central glutamate receptors, nitric oxide and soluble guanylyl cyclase in the inhibition by endotoxin of rat gastric acid secretion

2000

1. This study examines the role of a central pathway involving glutamate receptors, nitric oxide (NO) and cyclic GMP in the acute inhibitory effects of low doses of peripheral endotoxin on pentagastrin-stimulated acid production. 2. Vagotomy or intracisternal (i.c.) microinjections of the NO-inhibitor, N(G)-nitro-L-arginine methyl esther (L-NAME; 200 microg rat(-1)) restored acid secretory responses in endotoxin (10 microg kg(-1), i.v.)-treated rats. 3. The acid-inhibitory effect of i.v. endotoxin (10 microg kg(-1), i.v.) was prevented by prior i.c. administration of the NMDA receptor antagonists, dizocilpine maleate (MK-801; 10 nmol rat(-1)) and D-2-amino-5-phosphono-valeric acid (AP-5; 20…

Calcium dependence of the evoked arginine vasopressin release by electrical stimulation and by L-glutamate.

1989

l-Glutamate receptor binding in bovine retina

1982

Using a centrifugation technique saturable specific [ 3 H]glutamate binding in bovine retina could be demonstrated. Scatchard analysis revealed only one population of binding sites with a dissociation constant of about 3 μ m and a maximal number of binding sites of about 0·2 pmol/mg retinal protein. Several glutamic acid analogues inhibit specific [ 3 H]glutamate binding in bovine retina with half-maximal inhibitory concentrations similar to those reported in other areas of the CNS. Specific [ 3 H]glutamate binding and sodium dependent synaptosomal uptake of glutamate are largely concentrated in the P2 fraction of bovine retina homogenates consisting of conventionally sized synaptosomes. Th…

Excitotoxin-induced changes in transglutaminase during differentiation of cerebellar granule cells

2002

Excitotoxicity induced by NMDA receptor stimulation is able to increase the activity of many enzymes involved in neuronal cell death. Primary cultures of rat cerebellar granule cells were used to elucidate the role of transglutaminase reaction in the excitotoxic cell response, and to evaluate the role of glutamate receptors in cell survival and degeneration. Granule neurons, maintained in vitro for two weeks, were exposed to NMDA at different stages of differentiation. Following NMDA receptor activation, increases in transglutaminase activity were observed in cell cultures. The levels of enzyme activity were higher in cells at 5 days in vitro than in those at 8-9 or 13-14 days in vitro. Mor…

The Concise Guide To Pharmacology 2021/22: G Protein-Coupled Receptors

2021

The Concise Guide to PHARMACOLOGY 2021/22 is the fifth in this series of biennial publications. The Concise Guide provides concise overviews, mostly in tabular format, of the key properties of nearly 1900 human drug targets with an emphasis on selective pharmacology (where available), plus links to the open access knowledgebase source of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. Although the Concise Guide constitutes over 500 pages, the material presented is substantially reduced compared to information and links presented on the website. It provides a permanent, citable, point-in-time record that will s…

Age-dependent regulation of antioxidant genes by p38α MAPK in the liver

2018

p38α is a redox sensitive MAPK activated by pro-inflammatory cytokines and environmental, genotoxic and endoplasmic reticulum stresses. The aim of this work was to assess whether p38α controls the antioxidant defense in the liver, and if so, to elucidate the mechanism(s) involved and the age-related changes. For this purpose, we used liver-specific p38α-deficient mice at two different ages: young-mice (4 months-old) and old-mice (24 months-old). The liver of young p38α knock-out mice exhibited a decrease in GSH levels and an increase in GSSG/GSH ratio and malondialdehyde levels. However, old mice deficient in p38α had higher hepatic GSH levels and lower GSSG/GSH ratio than young p38α knock-…

Binuclear Cu2+ complex mediated discrimination between L-glutamate and L-aspartate in water.

2005

L-Glutamate and L-aspartate selectivity is achieved by the action of two Cu2+ metal ions rightly disposed in a cyclophanetype macrocyclic framework; electrochemical sensing of glutamate has been achieved by adsorption of the copper complexes on graphite electrodes. Verdejo Viu, Begoña, Begona.Verdejo@uv.es ; Domenech Carbo, Antonio, Antonio.Domenech@uv.es ; Jimenez Garcia, Hermas Rafael, Hermas.Jimenez@uv.es ; Soriano Soto, Concepción, Concepcion.Soriano@uv.es ; Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es