Search results for "aspartate"
showing 10 items of 195 documents
N-Acetylaspartate/Creatine and Choline/Creatine Ratios in the Thalami, Insular Cortex and White Matter as Markers of Hypertension and Cognitive Impai…
2008
International audience; Abstract: Our objective was to investigate the influence of hypertension on N-acetylaspartate (NAA) and choline (Cho) ratios in brain tissues in a community-dwelling elderly population. Brain flexibility was also evaluated with regard to the same metabolite ratios. Proton magnetic resonance spectroscopy (MRS) and the Trail Making Test (TMT) were performed in 80 subjects (75.7 +/- 4 years old) from the Three-City Study. Fifty-eight participants had hypertension. The NAA/creatine (Cr) and Cho/Cr ratios were obtained in the insular cortex, the thalami and the deep periventricular white matter. In addition, the B-A score of the TMT was evaluated. Uniand multi-variate ana…
Cannabinoid modulation of hippocampal long-term memory is mediated by mTOR signaling.
2009
Cognitive impairment is one of the most important negative consequences associated with cannabis consumption. We found that CB1 cannabinoid receptor (CB1R) activation transiently modulated the mammalian target of rapamycin (mTOR)/p70S6K pathway and the protein synthesis machinery in the mouse hippocampus, which correlated with the amnesic properties of delta9-tetrahydrocannabinol (THC). In addition, non-amnesic doses of either the mTOR blocker rapamycin or the protein synthesis inhibitor anisomycin abrogated the amnesic-like effects of THC, pointing to a mechanism involving new protein synthesis. Moreover, using pharmacological and genetic tools, we found that THC long-term memory deficits …
A population of prenatally generated cells in the rat paleocortex maintains an immature neuronal phenotype into adulthood.
2008
New neurons in the adult brain transiently express molecules related to neuronal development, such as the polysialylated form of neural cell adhesion molecule, or doublecortin (DCX). These molecules are also expressed by a cell population in the rat paleocortex layer II, whose origin, phenotype, and function are not clearly understood. We have classified most of these cells as a new cell type termed tangled cell. Some cells with the morphology of semilunar-pyramidal transitional neurons were also found among this population, as well as some scarce cells resembling semilunar, pyramidal. and fusiform neurons. We have found that none of these cells in layer II express markers of glial cells, m…
PSA-NCAM expression in the piriform cortex of the adult rat. Modulation by NMDA receptor antagonist administration.
2002
Administration of NMDA receptor antagonists upregulates the expression of the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) in the adult hippocampus. Since the piriform cortex is also populated by PSA-NCAM immunoreactive neurons during adulthood, we sought to characterize them in detail and to test whether NMDA receptor antagonists also modulate PSA-NCAM in this cortical region. PSA-NCAM immunoreactivity is located mainly in layer II, where many neurogliaform and some pyramidal-semilunar transitional neurons are labeled. Many large neurons in layer III and endopiriform nucleus also express PSA-NCAM. Interestingly, some small labeled cells resembling migratory neuroblas…
Acute effects of antidepressant drugs on long-term potentiation (LTP) in rat hippocampal slices.
1991
The actions of three clinically effective antidepressant drugs with different pharmacological profiles were investigated in the CA1 area of rat hippocampal slices. Imipramine and (+) or (-)-oxaprotiline had negligible effects on population spikes evoked by stratum radiatum stimulation, but reduced postsynaptic excitability in low Ca high Mg medium after an exposure of more than 15 min. Imipramine and (+)-oxaprotiline at 10 mumol/l enhanced long-term potentiation (LTP) when a lower stimulation strength was applied while (+)-oxaprotiline reduced LTP when a higher stimulus amplitude was used to evoke population spikes. (-)-oxaprotiline (levoprotiline) had a similar effect which was, however, n…
Neuroprotective effect of ceftriaxone on the penumbra in a rat venous ischemia model.
2012
Glutamate transporter-1 (GLT-1) maintains low concentrations of extracellular glutamate by removing glutamate from the extracellular space. It is controversial, however, whether upregulation of GLT-1 is neuroprotective under all ischemic/hypoxic conditions. Recently, a neuroprotective effect of preconditioning with a β-lactam antibiotic ceftriaxone (CTX) that increases expression of GLT-1 has been reported in animal models of focal ischemia. On the other hand, it is said that CTX does not play a neuroprotective role in an in vitro study. Thus, we examined the effect of CTX on ischemic injury in a rat model of two-vein occlusion (2VO). This model mimics venous ischemia during, e.g. tumor sur…
Neural overexcitation and implication of NMDA and AMPA receptors in a mouse model of temporal lobe epilepsy implying zinc chelation.
2006
Summary: Purpose: Zinc chelation with diethyldithiocarbamate (DEDTC) during nondamaging kainic acid administration enhances excitotoxicity to the level of cell damage. The objective of this work was to study the developing of the lesion in this model of temporal lobe epilepsy and the implications of the different types of glutamate receptors. Methods: The antagonist of the N-methyl-d-aspartate (NMDA) receptor MK-801, and the antagonist of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor GYKI52466, were used concomitantly with intraperitoneal administration of kainic acid (15 mg/kg) followed by DEDTC (150 mg/kg) in mouse. The animals were killed at different times from 4 …
Age as a Confounding Factor for the Accurate Non-Invasive Diagnosis of Advanced NAFLD Fibrosis
2017
OBJECTIVES Non-invasive fibrosis scores are widely used to identify/exclude advanced fibrosis in patients with non-alcoholic fatty liver disease (NAFLD). However, these scores were principally developed and validated in patients aged between 35 and 65 years of age. The objective of this study was to assess the effect of age on the performance of non-invasive fibrosis tests in NAFLD. METHODS Patients were recruited from European specialist hepatology clinics. The cohort was divided into five age-based groups: ≤35 (n=74), 36-45 (n=96), 46-55 (n=197), 56-64 (n=191), and ≥65 years (n=76), and the performance of the aspartate aminotransferase (AST)/alanine transaminase (ALT) ratio, fibrosis 4 (F…
A repetitive intracortical microstimulation pattern induces long-lasting synaptic depression in brain slices of the rat primary somatosensory cortex.
2000
Repetitive intracortical microstimulation (ICMS) applied to the rat primary somatosensory cortex (SI) in vivo was reported to induce reorganization of receptive fields and cortical maps. The present study was designed to exam- ine the effect of such an ICMS pattern applied to layer IV of brain slices containing SI on the efficacy of synaptic in- put to layer II/III. Effects of ICMS on the synaptic strength was quantified for the first synaptic component ( s1) of cor- tical field potentials (FPs) recorded from layer II/III of SI. FPs were evoked by stimulation in layer IV. The pattern of ICMS was identical to that used in vivo. However, stimula- tion intensity had to be raised to induce an a…
Prenatal exposure to the CB1 receptor agonist WIN 55,212-2 causes learning disruption associated with impaired cortical NMDA receptor function and em…
2005
The aim of this study was to investigate whether prenatal exposure to the cannabinoid CB1 receptor agonist WIN 55,212-2 (WIN) at a daily dose devoid of overt signs of toxicity and/or gross malformations (0.5 mg/kg, gestation days 5-20), influences cortical glutamatergic neurotransmission, learning and emotional reactivity in rat offspring. Basal and K+-evoked extracellular glutamate levels were significantly lower in cortical cell cultures obtained from pups exposed to WIN during gestation with respect to those measured in cultures obtained from neonates born from vehicle-treated dams. The addition of NMDA to cortical cell cultures from neonates born from vehicle-treated dams concentration-…