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Results 401 - 450 of 1835
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Vezmar Sandra - - 2003
Acute, subacute and chronic neurotoxicity have been observed after the administration of high-dose and/or intrathecal methotrexate (MTX). Acute toxicity is usually transient without permanent damage. Subacute and chronic toxicity are associated with changes in the brain and/or the spinal cord which may be progressive and even lead to coma and ...
Gargaglioni Luciane H - - 2003
The nucleus isthmi (NI) is a mesencephalic structure of the amphibian brain that has been reported to participate in CO(2) chemoreception and in the ventilatory response to hypoxia. In the present study, we assessed the role of glutamatergic transmission inside the NI on the hypoxic and hypercarbic drive to breathing. ...
Hong Yeon-Mi - - 2003
Calsenilin is a neuronal calcium binding protein that may function in calcium signaling and cell death. Kainic acid, an analog of the excitatory amino acid L-glutamate, produced excitotoxic cell death and induced the pathophysiology of status epilepticus. The expression of calsenilin was investigated in the mouse brain after kainic acid-induced ...
Maragos William F - - 2003
We have examined the neuroprotective efficacy of the mitochondrial uncoupler 2,4-dinitrophenol (DNP) in animals receiving striatal injections of the neurotoxin quinolinic acid. Animals administered DNP either 1 h before or 3 h following QA infusion developed lesions that were 25% smaller than control animals. Animals treated with the DNP analogue ...
Osorio-Rico Laura - - 2003
Kainic acid induces seizures and neurotoxicity in rats, produces changes in brain serotonin (5-HT), dopamine and noradrenaline metabolites among other changes in neurotransmitters. In this work, we investigated the changes in 5-HT turnover in brain regions from 84 rats intraperitoneally injected with kainic acid and a specific behavioural change, the ...
Bunch Lennart - - 2003
The design and synthesis of conformationally restricted analogues of alpha-amino acids is an often used strategy in medicinal chemistry research. Here we present the rational design, synthesis, and pharmacological evaluation of 2-azanorbornane-3-exo,5-endo-dicarboxylic acid (1), a novel conformationally restricted (S)-glutamic acid (Glu) analogue intended as a mimic of the folded Glu ...
Yamamoto Hiro-aki - - 2003
The effects of ganglioside GT1b or melatonin on damage to brain mitochondrial DNA (mtDNA) and seizures induced by kainic acid were investigated both in vivo and in vitro. An intraperitoneal (i.p.) injection of kainic acid (45 mg/kg) produced broad-spectrum limbic and severe sustained seizures in all of the treated mice. ...
De Sarro Giovambattista - - 2003
The anticonvulsant activities of some 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA)/kainate receptor antagonists, noncompetitive (2,3-benzodiazepines) and a competitive 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)-quinoxaline (NBQX), were compared in different experimental seizure models. In particular, compounds were evaluated against audiogenic seizure in DBA/2 mice, maximal electroshock seizure (MES) test and various chemoconvulsant models; both groups showed a protective action ...
Misu Yoshimi - - 2003
Historically, 3,4-dihydroxyphenylalanine (DOPA) has been believed to be an inert amino acid that alleviates the symptoms of Parkinson's disease by its conversion to dopamine via the enzyme aromatic L-amino acid decarboxylase. In contrast to this generally accepted idea, we propose that DOPA itself is a neurotransmitter and/or neuromodulator, in addition ...
Kim Hyoung-Chun - - 2003
The effects of dextromethorphan (DM), and its major metabolite dextrorphan (DX) on kainic acid-induced seizures in mice were examined. Intracerebroventricular DM or DX (5 or 10 microg/0.5 microl) pretreatment significantly attenuated seizures induced by kainic acid (0.07 microg/0.07 microl) in a dose-related manner. DM or DX pretreatment significantly attenuated kainic ...
Wang Jin - - 2003
Unilateral microinjection of Angiotensin-(1-7)[Ang-(1-7)] into the rostral ventrolateral medulla (RVLM) of anesthetized rats caused an increase in mean arterial pressure (MAP) accompanied by an increased release of excitatory amino acid (EAA) glutamate. In contrast, microinjection of Ang779, a selective antagonist of Ang-(1-7) receptor, into the RVLM caused a decrease in ...
Pszczolkowski Maciej A - - 2003
Calcium and glutamate receptor (GluR) agonists affect apple leaf consumption by neonates of the apple pest, the codling moth, Cydia pomonella (L.) Initial apple leaf consumption was advanced by the presence of trans-1-amino-(1S,3R)-cyclopentanedicarboxylic acid (trans-ACPD), but not by calcium chloride or N-methyl-D-aspartate (NMDA). However, during the 3 h following hatch, ...
O'Neal Patrick D - - 2003
The release of excitatory amino acids (EAAs) from injured neurons has been associated with secondary injury following head trauma. The development of a rapid and sensitive method for the quantification of EAAs may provide a means for clinical management of patients affected by head trauma. We explore the potential application ...
Ferhat Lotfi - - 2003
We have previously shown that, in HEK 293 cells, overexpression of acidic calponin, an actin-binding protein, induces remodeling of actin filaments, leading to a change in cell morphology. In addition, this protein is found in dendritic spines of adult hippocampal neurons. We hypothesized that this protein plays a role in ...
Bartolini Barbara - - 2003
Indole-3-pyruvic acid (IPA) undergoes in solutions to the keto-enol tautomerism, which appears responsible of its pharmacological effects, as only the enol tautomer is an easy target for oxygen free-radicals and can be transformed directly to kynurenic acid (KYNA). Contrary to expectations, the IPA enol tautomer is rather stable in mammalian ...
Verdaguer E - - 2003
The mechanisms underlying selective neuronal cell death in kainic acid-mediated neurodegeneration are not fully understood. We have recently demonstrated that in cerebellar granule neurons, kainic acid induces the expression of proteins associated with cell-cycle progression. In the present study we show that 3-amino thioacridone (3-ATA), a selective cyclin-dependent kinase 4 ...
Lapin I P - - 2003
The following NEKY have been studied: 1-kynurenine (KYN), 3-hydroxyKYN (3HKYN), kynurenic (KYNA), anthranilic (ANT), 3-hydroxyANT (3HANT), quinolinic (QUIN), picolinic (PICA), xanthurenic (XAN), nicotinic (NIC) acids, 3-indole-pyruvate (IPA), nicotinamide (NAM). NEKY antagonize the central effects of precursors of serotonin (tryptophan and 5-HTP), and tryptamine as well. Seizures induced by central administration ...
Qu Hong - - 2003
Limbic seizures were induced in rats by intraperitoneal injection of the glutamate receptor agonist kainic acid, followed, 24h later by injection of [1-13C]glucose and [1,2-13C]acetate. Analyses of forebrain extracts were performed using 13C magnetic resonance spectroscopy and HPLC. A significant increase in label derived from [1,2-13C]acetate was observed in glutamine ...
Hori N - - 2002
Electrical activity was recorded from motoneurons in adult mouse cervical spinal cord (C4-8) slices. Motoneurons showed almost no response to ionophoretic application of N-methyl-D-aspartic acid (NMDA) in both control and Mg(2+)-free media, but very sensitive to kainate (KA) and amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). Bath perfusion of KA, AMPA or glucose/O(2) free ...
Cho Jaeyoung - - 2002
A phosphatase and tensin homolog (PTEN) has been known to play multiple biological roles. However, role of PTEN in astrocyte activation is not clear yet. In the present study, the expression pattern of PTEN in the process of reactive gliosis was immunohistochemically examined in intracerebroventricular (i.c.v.) injected kainic acid mouse ...
Brown Julia - - 2002
P2Y receptor pharmacology is hampered by a lack of subtype selective antagonists. However, a recent study evaluated series of compounds, structurally related to the dye reactive blue 2, for their antagonist selectivity at P2X vs. P2Y receptors. Acid blue 129, acid blue 80, acid blue 25 and acid violet 34 ...
Manzini Ivan - - 2002
We report on responses of olfactory receptor neurons (ORNs) upon application of amino acids and forskolin using a novel slice preparation of the olfactory epithelium of Xenopus laevis tadpoles. Responses were measured using the patch-clamp technique. Both amino acids and forskolin proved to be potent stimuli. Interestingly, a number of ...
Zsizsik B K - - 2002
The dinoflagellate Lingulodinium polyedrum (syn. Gonyaulax polyedra) was used as a model organism for studying the effects of high and low physiological oxidative stress on the formation of kynurenic and xanthurenic acids from kynurenine and 3-hydroxykynurenine. Cell were incubated with the precursors and exposed to light (high physiological stress due ...
O'Shea R D - - 2002
1. Glutamate transporters (also known as excitatory amino acid transporters or EAAT) are solely responsible for the removal of the excitatory neurotransmitter l-glutamate (Glu) from the extracellular space and, thus, permit normal transmission, as well as preventing cell death due to the excessive activation of Glu receptors. 2. Five subtypes ...
Wolosker Herman - - 2002
D-Amino acids have been known to be present in bacteria for more than 50 years, but only recently they were identified in mammals. The occurrence of D-amino acids in mammals challenge classic concepts in biology in which only L-amino acids would be present or thought to play important roles. Recent ...
Lo Wan-Chen - - 2002
Carbon monoxide (CO) has been identified as an endogenous biological messenger in the brain. Heme oxygenase catalyzes the metabolism of heme to biliverdin and CO. Recent studies have demonstrated that CO is involved in central cardiovascular regulation and modulates the baroreflex in the nucleus tractus solitarii of rats. The purpose ...
Fukumoto Shen-ichiro - - 2002
To elucidate the role of the perirhinal cortex (PRC) in experimental epilepsy, the effects of the lesion of the PRC on kainic acid (KA)-induced limbic seizure were investigated. The PRC lesion was made by means of ibotenic acid (IBO) microinjection. The electroencephalogram in the PRC-lesioned rats demonstrated suppression of the ...
Kuffler D P - - 2002
Cellular mechanisms underlying defense reactions induced by noxious heat and acids were studied in frogs (Rana pipiens) by measuring whole cell membrane currents in cultured dorsal root ganglion (DRG) neurons. Seventy-eight of 82 DRG neurons exposed to 3-s ramps of increasing temperature to 48 degrees C exhibited an inward current ...
Moloney Mark G - - 2002
Recent developments in the understanding of the molecular function of memory and other CNS-mediated processes have arisen from the multidisciplinary interplay of excitatory amino acid synthesis and medicinal chemistry, X-ray crystallographic structural protein analysis, molecular biology, pharmacology and physiology. This review seeks to place recent synthetic developments of EAA analogues ...
Luchowski Piotr - - 2002
The aim of the present study was to evaluate the effect of mitochondrial inhibitors, 1-methyl-4-phenylpyridinium (MPP(+)) and 3-nitropropionic acid (3-NPA), on the brain production of endogenous glutamate antagonist, kynurenic acid (KYNA). MPP(+) and 3-NPA dose-dependently impaired the synthesis of KYNA in rat cortical slices. Enzymatic studies revealed that MPP(+) inhibits ...
D'Aniello Antimo - - 2002
Recently we demonstrated that N-methyl-D-aspartic acid (NMDA) is present as an endogenous compound in the nervous tissues and endocrine glands of the rat where it plays a role in the regulation of the luteinizing hormone, growth hormone, and prolactin (FASEB J. 14 (2000) 699; Endocrinology 141 (2000) 3861). Based on ...
Yue Wang - - 2002
AIM: To investigate the effects and mechanism of succinic acid on pentylenetetrazol (PTZ) chemical kindling and amygdala electrical kindling in rats. METHODS: PTZ chemical kindling and amygdala electrical kindling models were established in rats. The effects of succinic acid on the behavior and afterdischarge of kindled rats were observed. The ...
Shin Rick S - - 2002
A neurochemical basis for many of the epilepsies has long been suspected to result from an imbalance between excitatory and inhibitory neurotransmitter mechanisms. Data supporting changes in extrasynaptic amino acid levels during epileptogenesis, however, remain controversial. In the present study, we used in vivo microdialysis to measure the levels of ...
Tutka Piotr - - 2002
The influence of molsidomine, a donor of nitric oxide (NO), L-arginine, a substrate for NO synthesis, and N(G)-nitro-L-arginine (NNA), an inhibitor of NO synthase, on the protective activity of CGP 40116, GYKI 52466, MK-801, and riluzole against electroconvulsions was studied in mice. Molsidomine (100 mg kg(-1); i.p.) potentiated the protective ...
Rejdak Robert - - 2002
BACKGROUND: Kynurenic acid (KYNA) is the only known endogenous glutamate receptor antagonist and neuroprotectant. After showing the presence of KYNA and its synthesising enzymes in the adult rat retina, we examined developmental changes of KYNA content in both vascularised rat and avascular chicken retinas. METHODS: Retinas from Brown Norway rats ...
Kekesi Gabriella - - 2002
Kynurenic acid as an endogenous ligand antagonizes all types of ionotropic glutamate receptors, with preferential affinity for the glycine-binding site of the N-methyl-D-aspartate (NMDA) receptor. The purpose of the present study was to investigate the antinociceptive potency of continuously administered kynurenic acid on carrageenan-induced thermal hyperalgesia by means of a ...
Galvan-Arzate Sonia - - 2002
The effects of diethylpropion (DEP), an amphetamine derivative and a well-known anorectic agent, on different neurochemical and behavioral markers of toxicity in rats were evaluated. Animals received a daily dose of DEP (5 mg/kg po) for 15 days, and all tests were performed 24 hours after the last DEP administration. ...
Yamada Yasuhito - - 2002
To elucidate the possible roles of the caudate-putamen (CP) on the development of amygdala (AM) kindling and AM-kindled seizures, the bilateral CP were destroyed by intra-CP injection of ibotenic acid (0.5 or 1.0 microg per side) before the AM kindling or after completion of the AM kindling. Prior destruction of ...
Engelmann Mario - - 2002
The effect of direct intrahypothalamic nitric oxide (NO) administration on the release of selected amino acids in the hypothalamic supraoptic nucleus (SON) with and without concomitant forced swimming was investigated. Adult male Wistar rats were chronically fitted with U-shaped microdialysis probes in the SON and forced to swim for 10-min ...
Ravindranath Vijayalakshmi - - 2002
beta-N-Oxalyl amino-L-alanine (L-BOAA); synonym beta-N-oxalyl-alpha,beta-diaminopropionic acid (beta-ODAP) is a naturally occurring non-protein amino acid present in the chickling pea from the plant Lathyrus sativus grown in drought prone areas. Ingestion of L-BOAA as a staple diet results in a progressive neurodegenerative condition, neurolathyrism, a form of motor neuron disease which ...
Mignani Serge - - 2002
Excessive release of glutamate, a potent excitatory neurotransmitter, is thought to play an important role in a variety of acute and chronic neurological disorders, suggesting that excitatory amino acid antagonists may have broad therapeutic potential in neurology. Here, we describe the synthesis, pharmacological properties and neuroprotective activity of 9-carboxymethyl-imidazo-[1-2a]indeno[1-2e]pyrazin-4-one-2-carboxylic acid ...
Hashimoto Kimiko - - 2002
Kainoid amino acids are agonists of the AMPA/kainate receptors and exhibit highly potent neuroexcitatory activity. From the results of extensive structure--activity relationship studies, we previously postulated that the C4-substituent of the kainoid amino acids interacts with an allosteric site of the glutamate receptor with electron-donating character. In order to investigate ...
Xu Yan-Jun - - 2002
BACKGROUND: Lysophosphatidic acid, a bioactive phospholipid, is mainly released from the activated platelets. The concentration of lysophosphatidic acid in serum is elevated under conditions such as ischemia, hypertension, and thrombosis; however, its effect on cardiac function, as well as the mechanisms of its action, have not been fully understood. METHODS ...
Mohanan P V - - 2002
The effects of kainic acid on mitochondria DNA (mtDNA) or lipid peroxidation in mice brain and, preventive effects of melatonin against its effects were investigated in vivo. Broad-spectrum limbic and severe sustained seizures were observed in all mice when kainic acid (45 mg/kg) was injected intraperitoneally (ip) to eight mice. ...
Lipschitz David L - - 2002
The olfactory epithelium (OE) of zebrafish is populated with ciliated and microvillar olfactory sensory neurons (OSNs). Whether distinct classes of odorants specifically activate either of these unique populations of OSNs is unknown. Previously we demonstrated that zebrafish OSNs could be labeled in an activity-dependent fashion by amino acid but not ...
Batueva I V - - 2002
Studies were performed on spinal neurons from lampreys isolated by an enzymatic/mechanical method using pronase. The effects of 100 microM serotonin (5-HT) on membrane potential oscillations induced by a variety of excitatory amino acids were studied. 5-HT was found to depolarize branched cells (presumptive motoneurons and interneurons) by 2-6 mV ...
Owji A A - - 2002
High concentrations of glucagon-like peptide-1 (7-36) amide (GLP-1) and its specific receptor (GLP-1R) have been found in the rat hypothalamus. In this study the actions of GLP-1 and its related peptides, exendin-4 (GLP-1R agonist), exendin (9-39) (GLP-1R antagonist) and GLP-1 (9-36) amide (the major GLP-1 metabolite) on levels of serotonin ...
Behan W M H - - 2002
1. Quinolinic acid may be an important endogenous excitotoxin, but its concentrations in brain are low. We have therefore attempted to determine whether its neurotoxicity can be increased by the simultaneous presence of free radicals. 2. Quinolinic acid was injected into the hippocampus of anaesthetized rats at doses of 40 ...
Rossato Janine I - - 2002
Ebselen (EBS) is a seleno-organic compound with glutathione peroxidase-like activity which is neuroprotective in acute stroke ischemia. In this study, we investigated the effect of EBS on quinolinic acid (QA)-induced neurotoxicity. EBS inhibited QA-induced production of thiobarbituric acid reactive species (TBARS) by striatal homogenates in vitro with an IC(50) of ...
Tirapelli Carlos R - - 2002
ent-kaurenoic acid (KA) isolated from Viguiera robusta was tested for activity on vascular smooth muscle contactility. Cumulative concentration-response curves were obtained for a stepwise increase (10(-10)-10(-05) mol/l) in the concentration of phenylephrine (Phe), a selective alpha(1)-adrenergic agonist. The effects in the presence of KA (0.2, 2.0 and 20.0 microg/ml), and ...
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