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Nmda modulation

Andrei Tsentsevitsky, Leniz Nurullin, Evgeny Nikolsky, Artem Malomouzh
There is some evidence that glutamate (Glu) acts as a signaling molecule at vertebrate neuromuscular junctions where acetylcholine (ACh) serves as a neurotransmitter. In this study, performed on the cutaneous pectoris muscle of the frog Rana ridibunda, Glu receptor mechanisms that modulate ACh release processes were analyzed. Electrophysiological experiments showed that Glu reduces both spontaneous and evoked quantal secretion of ACh and synchronizes its release in response to electrical stimulation. Quisqualate, an agonist of ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptors and metabotropic Group I mGlu receptors, also exerted Glu-like inhibitory effects on the secretion of ACh but had no effect on the kinetics of quantal release...
October 22, 2016: Journal of Neuroscience Research
Mark Galizio, Brooke April, Melissa Deal, Andrew Hawkey, Danielle Panoz-Brown, Ashley Prichard, Katherine Bruce
The Odor Span Task is an incrementing non-matching-to-sample procedure that permits the study of behavior under the control of multiple stimuli. Rats are exposed to a series of odor stimuli and selection of new stimuli is reinforced. Successful performance thus requires remembering which stimuli have previously been presented during a given session. This procedure has been frequently used in neurobiological studies as a rodent model of working memory; however, only a few studies have examined the effects of drugs on performance in this task...
October 17, 2016: Journal of the Experimental Analysis of Behavior
Erik Nylander, Alfhild Grönbladh, Sofia Zelleroth, Shanti Diwakarla, Fred Nyberg, Mathias Hallberg
Human growth hormone (GH) displays promising protective effects in the central nervous system after damage caused by various insults. Current evidence suggests that these effects may involve N-methyl-D-aspartate (NMDA) receptor function, a receptor that also is believed to play a role in opioid-induced neurotoxicity. The aims of the present study were to examine the acute toxic effects of methadone, an opioid receptor agonist and NMDA receptor antagonist, as well as to evaluate the protective properties of recombinant human GH (rhGH) on methadone-induced toxicity...
October 13, 2016: Neuroscience
Guy Griebel, Philippe Pichat, Denis Boulay, Vanessa Naimoli, Lisa Potestio, Robert Featherstone, Sukhveen Sahni, Henry Defex, Christophe Desvignes, Franck Slowinski, Xavier Vigé, Olivier E Bergis, Rosy Sher, Raymond Kosley, Sathapana Kongsamut, Mark D Black, Geoffrey B Varty
Normalization of altered glutamate neurotransmission through activation of the mGluR2 has emerged as a new approach to treat schizophrenia. These studies describe a potent brain penetrant mGluR2 positive allosteric modulator (PAM), SAR218645. The compound behaves as a selective PAM of mGluR2 in recombinant and native receptor expression systems, increasing the affinity of glutamate at mGluR2 as inferred by competition and GTPγ(35)S binding assays. SAR218645 augmented the mGluR2-mediated response to glutamate in a rat recombinant mGluR2 forced-coupled Ca(2+) mobilization assay...
October 13, 2016: Scientific Reports
Marco Bacigaluppi, Gianluca Luigi Russo, Luca Peruzzotti-Jametti, Silvia Rossi, Stefano Sandrone, Erica Butti, Roberta De Ceglia, Andrea Bergamaschi, Caterina Motta, Mattia Gallizioli, Valeria Studer, Emanuela Colombo, Cinthia Farina, Giancarlo Comi, Letterio Salvatore Politi, Luca Muzio, Claudia Villani, Roberto William Invernizzi, Dirk Matthias Hermann, Diego Centonze, Gianvito Martino
: Ischemic stroke is the leading cause of disability, but effective therapies are currently widely lacking. Recovery from stroke is very much dependent on the possibility to develop treatments able to both halt the neurodegenerative process as well as to foster adaptive tissue plasticity. Here we show that ischemic mice treated with neural precursor cell (NPC) transplantation had on neurophysiological analysis, early after treatment, reduced presynaptic release of glutamate within the ipsilesional corticospinal tract (CST), and an enhanced NMDA-mediated excitatory transmission in the contralesional CST...
October 12, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Lisa Gasperini, Elisa Meneghetti, Giuseppe Legname, Federico Benetti
Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defined mechanisms. Prion protein, for instance, interacts with divalent cations via multiple metal-binding sites and it modulates several metal-dependent physiological functions, such as S-nitrosylation of NMDA receptors...
2016: Frontiers in Neuroscience
Ting Ting Zhao, Keon Sung Shin, Hyun Jin Park, Kyung Sook Kim, Kung Eun Lee, Yoon Jeong Cho, Myung Koo Lee
This study investigated the effects of (-)-sesamin on memory deficits induced by chronic electric footshock (EF)-induced stress in mice. Mice were treated with (-)-sesamin (25 and 50mg/kg, p.o., daily for 21day) prior to chronic EF stress (0.6mA, 1s every 5s for 3min, daily for 21day). Transfer retention latencies in the elevated plus maze test and N-methyl-d-aspartate (NMDA) receptor (type 1) phosphorylation in the hippocampus increased with chronic EF stress, and they were reduced by treatment with (-)-sesamin at both doses...
October 4, 2016: Neuroscience Letters
Keith L Shelton
Inhalants are a loosely organized category of abused compounds defined entirely by their common route of administration. Inhalants include volatile solvents, fuels, volatile anesthetics, gasses, and liquefied refrigerants, among others. They are ubiquitous in modern society as ingredients in a wide variety of household, commercial, and medical products. Persons of all ages abuse inhalants but the highest prevalence of abuse is in younger adolescents. Although inhalants have been shown to act upon a host of neurotransmitter receptors, the stimulus effects of the few inhalants which have been trained or tested in drug discrimination procedures suggest that their discriminative stimulus properties are mediated by a few key neurotransmitter receptor systems...
October 7, 2016: Current Topics in Behavioral Neurosciences
Birgit Rössner, Maximilian Klingler, Tanja Bulat, Ajinkya Sase, Andrea Zeilinger, Melanie Spitzwieser, Jana Aradska, Margit Cichna-Markl, Gert Lubec
AMPA receptors mediate most fast excitatory synaptic transmission in the brain. Highly dynamic AMPA receptors are subjected to trafficking, recycling, and/or degradation and replacement. Changes in AMPA receptor abundance is an important mechanism involved in learning and memory formation. Results obtained with the Morris water maze (MWM), a paradigm for testing spatial memory in rodent, correlate with hippocampal synaptic plasticity and NMDA function. Different phases of spatial learning like acquisition and retrieval involve AMPA receptors...
October 6, 2016: Amino Acids
Sudarat Nimitvilai, Chang You, Devinder S Arora, Maureen A McElvain, Bertha J Vandegrift, Mark S Brodie, John J Woodward
Drugs of abuse increase the activity of dopaminergic neurons of the ventral tegmental area (VTA), and output from the VTA is critical for both natural and drug-induced reward and reinforcement. Ethanol and the abused inhalant toluene both enhance VTA neuronal firing, but the mechanisms of this effect is not fully known. In this study, we used extracellular recordings to compare the actions of toluene and ethanol on DA VTA neurons. Both ethanol and toluene increased the firing rate of DA neurons, although toluene was ~100 times more potent than ethanol...
2016: Frontiers in Neuroscience
Meilin Tian, Shixin Ye
Allostery is essential to neuronal receptor function, but its transient nature poses a challenge for characterization. The N-terminal domains (NTDs) distinct from ligand binding domains are a major locus for allosteric regulation of NMDA receptors (NMDARs), where different modulatory binding sites have been observed. The inhibitor ifenprodil, and related phenylethanoamine compounds specifically targeting GluN1/GluN2B NMDARs have neuroprotective activity. However, whether they use differential structural pathways than the endogenous inhibitor Zn(2+) for regulation is unknown...
October 7, 2016: Scientific Reports
Devesh Mishra, Jose Ignacio Pena-Bravo, Kah-Chung Leong, Antonieta Lavin, Carmela M Reichel
World-wide methamphetamine (meth) use is increasing at a rapid rate; therefore, it has become increasingly important to understand the synaptic changes and neural mechanisms affected by drug exposure. In rodents, 6-h access to contingent meth results in an escalation of drug intake and impaired cognitive sequelae typically associated with changes within the corticostriatal circuitry. There is a dearth of knowledge regarding the underlying physiological changes within this circuit following meth self-administration...
October 5, 2016: Brain Structure & Function
Moritz Armbruster, Elizabeth Hanson, Chris G Dulla
: Excitatory amino acid transporters (EAATs) are abundantly expressed by astrocytes, rapidly remove glutamate from the extracellular environment, and restrict the temporal and spatial extent of glutamate signaling. Studies probing EAAT function suggest that their capacity to remove glutamate is large and does not saturate, even with substantial glutamate challenges. In contrast, we report that neuronal activity rapidly and reversibly modulates EAAT-dependent glutamate transport. To date, no physiological manipulation has shown changes in functional glutamate uptake in a nonpathological state...
October 5, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Andrei Rozov, Nail Burnashev
Suppression of NMDA receptor (NMDAR)-mediated currents by intracellular Ca(2+) has been described as a negative feedback loop in NMDAR modulation. In the time scale of tenths of milliseconds the depth of the suppression does not depend on the Ca(2+) source. It may be caused by Ca(2+) influx through voltage-gated calcium channels, NMDAR channels or release from intracellular stores. However, NMDARs are often co-expressed in synapses with Ca(2+)-permeable AMPA receptors (AMPARs). Due to significant differences in activation kinetics between these two types of glutamate receptors (GluRs), Ca(2+) entry through AMPARs precedes full activation of NMDARs, and therefore, might have an impact on the amplitude of NMDAR-mediated currents...
September 28, 2016: Cell Calcium
Danielle M Osborne, Kelsey E O'Leary, Dennis P Fitzgerald, Alvin J George, Michael M Vidal, Brian M Anderson, Ewan C McNay
AIMS/HYPOTHESIS: Recurrent hypoglycaemia is primarily caused by repeated over-administration of insulin to patients with diabetes. Although cognition is impaired during hypoglycaemia, restoration of euglycaemia after recurrent hypoglycaemia is associated with improved hippocampally mediated memory. Recurrent hypoglycaemia alters glucocorticoid secretion in response to hypoglycaemia; glucocorticoids are well established to regulate hippocampal processes, suggesting a possible mechanism for recurrent hypoglycaemia modulation of subsequent cognition...
September 29, 2016: Diabetologia
Andrea Cabrera-Pastor, Marta Llansola, Vicente Felipo
Extracellular protein kinases, including cAMP-dependent protein kinase (PKA), modulate neuronal functions including N-methyl-d-aspartate (NMDA) receptor-dependent long-term potentiation. NMDA receptor activation increases calcium, which binds to calmodulin and activates nitric oxide synthase (NOS), increasing nitric oxide (NO), which activates guanylate cyclase, increasing cGMP, which is released to the extracellular fluid, allowing analysis of this glutamate-NO-cGMP pathway in vivo by microdialysis. The function of this pathway is impaired in hyperammonemic rats...
October 5, 2016: ACS Chemical Neuroscience
Fa-Ping Tu, Jun-Xiang Li, Qiang Li, Ji Wang
BACKGROUND: Hepatic ischemia/reperfusion (hepatic I/R) has been found to induce cognitive dysfunction. The NR2B subunit of N-methyl-D-aspartate (NMDA) receptors is a major factor in memory and learning processes, and hydrogen sulfide (H2S) may modulate this NMDA receptor. Therefore, in this study, sodium hydrosulfide (NaHS, a donor of H2S) was administered in an animal model of hepatic I/R to investigate the effects of H2S on cognitive impairment and expression of NR2B. MATERIALS AND METHODS: NaHS (5 mg/kg) or normal saline was administered intraperitoneally once a day for 11 consecutive days, during which a rat model of 70% hepatic I/R was established on the fourth day...
October 2016: Journal of Surgical Research
Saigeet Eleti
BACKGROUND: Alzheimer's dementia is one of the most significant health burdens of the modern age in both industrialised and non-industrialised nations as it is a major cause of morbidity and functional impairment in the elderly. Currently there are no cures for progressive dementias, including Alzheimer's disease, and no treatments that would modify their progress. Intervention involves pharmacological treatment to temporarily relieve the symptoms, including three cholinesterase inhibitors and a noncompetitive NMDA antagonist, and the efficacy of these is widely debated...
September 2016: Psychiatria Danubina
Shujia Zhu, Eric Gouaux
Ionotropic glutamate receptors (iGluRs) transduce signals derived from release of the excitatory neurotransmitter glutamate from pre-synaptic neurons into excitation of post-synaptic neurons on a millisecond time-scale. In recent years, the elucidation of full-length iGluR structures of NMDA, AMPA and kainate receptors by X-ray crystallography and single particle cryo-electron microscopy has greatly enhanced our understanding of the interrelationships between receptor architecture and gating mechanism. Here we briefly review full-length iGluR structures and discuss the similarities and differences between NMDA receptors and non-NMDA iGluRs...
September 20, 2016: Neuropharmacology
Adriana Pinto de Freitas, Danielle Dias Pinto Ferreira, Arlete Fernandes, Robertta Silva Martins, Vladimir Pedro Peralva Borges-Martins, Matheus Figueiredo Sathler, Maurício Dos-Santos-Pereira, Roberto Paes-de-Carvalho, Elizabeth Giestal-de-Araujo, Ricardo Augusto de Melo Reis, Regina Celia Cussa Kubrusly
l-Glutamate and l-aspartate are the main excitatory amino acids (EAAs) in the Central Nervous System (CNS) and their uptake regulation is critical for the maintenance of the excitatory balance. Excitatory amino acid transporters (EAATs) are widely distributed among central neurons and glial cells. GLAST and GLT1 are expressed in glial cells, whereas excitatory amino acid transporter 3/excitatory amino acid carrier 1 (EAAT3/EAAC1) is neuronal. Different signaling pathways regulate glutamate uptake by modifying the activity and expression of EAATs...
September 20, 2016: Neuroscience
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