Search results for "aspartate"
showing 10 items of 195 documents
Changes in NMDA-receptor function in the first week following laser-induced lesions in rat visual cortex.
2011
Focal brain injuries are accompanied by processes of functional reorganization that partially compensate the functional loss. In a previous study, extracellular recordings at the border of a laser-induced lesion in the visual cortex of rats showed an enhanced synaptic plasticity, which was mediated by the activity of NR2B-contaning NMDA-receptors (NMDARs) shedding light on the potential cellular mechanisms underlying this reorganization. Given the potentially important contribution of NMDARs in processes of functional reorganization, in the present study, we used the same lesion model to further investigate lesion-induced changes in function and localization of NMDARs in the vicinity of the…
The role of N-methyl-D-asparate receptors in neurogenesis.
2006
The dentate gyrus continues to incorporate granule neurons during adulthood. Among the factors that we know modulate adult neurogenesis in the dentate gyrus, one of the first studied was the influence of excitatory amino-acids. These neurotransmitters, acting through NMDA receptors, are able to modulate both the proliferation of progenitor cells as well as the rate of neurogenesis in the adult dentate gyrus. However, the mechanisms by which these processes are influenced are not clearly known. Although there is no anatomical evidence of NMDA receptor expression in adult hippocampal progenitor cells or differentiating granule neurons, electrophysiological data and in vitro studies suggest th…
The neurochemistry of autism
2020
Autism spectrum disorder (ASD) refers to complex neurobehavioral and neurodevelopmental conditions characterized by impaired social interaction and communication, restricted and repetitive patterns of behavior or interests, and altered sensory processing. Environmental, immunological, genetic, and epigenetic factors are implicated in the pathophysiology of autism and provoke the occurrence of neuroanatomical and neurochemical events relatively early in the development of the central nervous system. Many neurochemical pathways are involved in determining ASD; however, how these complex networks interact and cause the onset of the core symptoms of autism remains unclear. Further studies on ne…
PRELIMINARY-OBSERVATIONS OF METABOLIC CHARACTERIZATION OF BILATERAL TEMPORAL EPILEPTIC FOCUS, USING PROTON MAGNETIC-RESONANCE SPECTROSCOPY - 3 CASES
1994
International audience; Abstract: The authors report the case of 3 patients with bilateral temporal lobe epilepsy demonstrated by EEG and sphenoidal electrodes. Two out of the 3 patients presented with childhood febrile convulsions. Their neurological and mental examination was normal. EEG showed spikes within the anterior part of the 2 temporal lobes. CT scan and MRI showed no atrophic lesion within the 2 temporal lobes. Proton magnetic resonance spectroscopy, performed within a cube of 8 cube-centimetres localized in the anterior part of the 2 temporal lobes showed a significant decrease of N-acetyl-aspartate in the 2 temporal lobes of the 3 cases, compared with controls matched with age,…
GABA-A Receptors Regulate Neocortical Neuronal Migration In Vitro and In Vivo
2006
The cortical migration process depends on a number of trophic factors and on the activation of different voltage- and ligand-gated channels. We investigated the role of gamma-aminobutyric acid (GABA) type A receptors in the neuronal migration process of the newborn rat parietal cortex in vivo and in vitro. Local in vivo application of the GABA-A antagonist bicuculline methiodide (BMI) or the agonist muscimol via cortical surface Elvax implants induced prominent alterations in the cortical architecture when compared with untreated or sham-operated controls. BMI- and muscimol-treated animals revealed heterotopic cell clusters in the upper layers and a complete loss of the cortical lamination …
Postsynaptic NO/cGMP Increases NMDA Receptor Currents via Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels in the Hippocampus
2013
The nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling cascade participates in the modulation of synaptic transmission. The effects of NO are mediated by the NO-sensitive cGMP-forming guanylyl cyclases (NO-GCs), which exist in 2 isoforms with indistinguishable regulatory properties. The lack of long-term potentiation (LTP) in knock-out (KO) mice deficient in either one of the NO-GC isoforms indicates the contribution of both NO-GCs to LTP. Recently, we showed that the NO-GC1 isoform is located presynaptically in glutamatergic neurons and increases the glutamate release via hyperpolarization-activated cyclic nucleotide (HCN)-gated channels in the hippocampus. Electrophysiologi…
Synaptopodin regulates denervation-induced homeostatic synaptic plasticity
2013
Synaptopodin (SP) is a marker and essential component of the spine apparatus (SA), an enigmatic cellular organelle composed of stacked smooth endoplasmic reticulum that has been linked to synaptic plasticity. However, SP/SA-mediated synaptic plasticity remains incompletely understood. To study the role of SP/SA in homeostatic synaptic plasticity we here used denervation-induced synaptic scaling of mouse dentate granule cells as a model system. This form of plasticity is of considerable interest in the context of neurological diseases that are associated with the loss of neurons and subsequent denervation of connected brain regions. In entorhino-hippocampal slice cultures prepared from SP-de…
Pathway-specificity in N-methyl-d-aspartate receptor-mediated synaptic inputs onto subplate neurons
2007
The subplate plays an important role in forming neuronal connections during early cortical development. We characterized by the use of whole-cell and cell-attached patch-clamp recordings in coronal brain slices from newborn mice (postnatal day [P] 0-3) the functional properties of two major pathways onto subplate neurons (SPn), the thalamocortical and the intra-subplate synaptic input. The two afferent pathways were stimulated extracellularly with bipolar electrodes placed in the thalamus and the subplate, respectively. Synaptically evoked and pharmacologically isolated N-methyl-d-aspartate receptor (NMDAR) -mediated responses with an onset latency of approximately 6 ms could be reliably re…
Atypical presentation of anti-N-methyl-D-aspartate receptor encephalitis: two case reports
2017
Abstract Background Anti-N-methyl-D-aspartate receptor encephalitis is a rare autoimmune disease characterized by severe neurological and psychiatric symptoms and a difficult diagnosis. The disease is often secondary to a neoplastic lesion, seldom diagnosed years later. Psychiatric symptoms are prevalent in adults; neurologic symptoms are more evident in children, who typically present primarily with neurological symptoms. To the best of our knowledge, the association with juvenile idiopathic arthritis has not been described. Case presentation We report the cases of two caucasian girls with an atypical presentation. The first patient was an 8-year-old girl with normal psychomotor developmen…
Memantine does not block antiaggressive effects of morphine in mice.
2002
The action of the noncompetitive N-methyl-D-aspartate (NMDA) receptor blocker memantine (5, 10, 20 and 40 mg/kg) was evaluated during social encounters in mice. Although a dose-dependent increase in locomotion was observed, only with the highest dose did it reach statistical significance. Aggressive behavior was decreased with 20 and 40 mg/kg of memantine, social contacts being increased only with 20 mg/kg. Subsequently, the effect of these memantine doses on the antiaggressive actions of morphine (10 mg/kg) was evaluated. None of the doses affected the antiaggressive action of morphine. As memantine administration produced an antiaggressive effect only at doses that affected locomotion, it…