Search results for "neuron"

Focal Cortical Lesions Induce Bidirectional Changes in the Excitability of Fast Spiking and Non Fast Spiking Cortical Interneurons

2014

A physiological brain function requires neuronal networks to operate within a well-defined range of activity. Indeed, alterations in neuronal excitability have been associated with several pathological conditions, ranging from epilepsy to neuropsychiatric disorders. Changes in inhibitory transmission are known to play a key role in the development of hyperexcitability. However it is largely unknown whether specific interneuronal subpopulations contribute differentially to such pathological condition. In the present study we investigated functional alterations of inhibitory interneurons embedded in a hyperexcitable cortical circuit at the border of chronically induced focal lesions in mouse …

Semilunar Granule Cells Are the Primary Source of the Perisomatic Excitatory Innervation onto Parvalbumin-Expressing Interneurons in the Dentate Gyrus

2020

AbstractWe analyzed the origin and relevance of the perisomatic excitatory inputs on the parvalbumin interneurons of the granule cell layer in mouse. Confocal analysis of the glutamatergic innervation showed that it represents ∼50% of the perisomatic synapses that parvalbumin cells receive. This excitatory input may originate from granule cell collaterals, the mossy cells, or even supramammillary nucleus. First, we assessed the input from the mossy cells on parvalbumin interneurons. Axon terminals of mossy cells were visualized by their calretinin content. Using multicolor confocal microscopy, we observed that less than 10% of perisomatic excitatory innervation of parvalbumin cells could or…

In Vivo Reprogramming for Brain and Spinal Cord Repair.

2015

AbstractCell reprogramming technologies have enabled the generation of various specific cell types including neurons from readily accessible patient cells, such as skin fibroblasts, providing an intriguing novel cell source for autologous cell transplantation. However, cell transplantation faces several difficult hurdles such as cell production and purification, long-term survival, and functional integration after transplantation. Recently,in vivoreprogramming, which makes use of endogenous cells for regeneration purpose, emerged as a new approach to circumvent cell transplantation. There has been evidence forin vivoreprogramming in the mouse pancreas, heart, and brain and spinal cord with …

Study of the population of immature neurons in the adult piriform cortex layer II

2019

Physiological studies indicate that the piriform or primary olfactory cortex of adult mammals exhibits a high degree of synaptic plasticity. Interestingly, a subpopulation of cells in the layer II of the adult piriform cortex expresses neurodevelopmental markers, such as the polysialylated form of neural cell adhesion molecule (PSA-NCAM) or doublecortin (DCX). This study analyzes the nature, origin, and potential function of these poorly understood cells in mice. As previously described in rats, most of the PSANCAM expressing cells in layer II could be morphologically classified as tangled cells and only a small proportion of larger cells could be considered semilunar-pyramidal transitional…

Pharmacological activation of CB2 receptors counteracts the deleterious effect of ethanol on cell proliferation in the main neurogenic zones of the a…

2015

Chronic alcohol exposure reduces endocannabinoid activity and disrupts adult neurogenesis in rodents, which results in structural and functional alterations. Cannabinoid receptor agonists promote adult neural progenitor cell (NPC) proliferation. We evaluated the protective effects of the selective CB1 receptor agonist ACEA, the selective CB2 receptor agonist JWH133 and the fatty-acid amide-hydrolase (FAAH) inhibitor URB597, which enhances endocannabinoid receptor activity, on NPC proliferation in rats with forced consumption of ethanol (10%) or sucrose liquid diets for 2 weeks. We performed immunohistochemical and stereological analyses of cells expressing the mitotic phosphorylation of his…

Effect of some illegal drug in sport (AAS) on neuron-like cells (PC12)

2011

Statins and the squalene synthase inhibitor zaragozic acid stimulate the non-amyloidogenic pathway of amyloid-beta protein precursor processing by su…

2010

Cholesterol-lowering drugs such as statins influence the proteolytic processing of the amyloid-beta protein precursor (AbetaPP) and are reported to stimulate the activity of alpha-secretase, the major preventive secretase of Alzheimer's disease. Statins can increase the alpha-secretase activity by their cholesterol-lowering properties as well as by impairment of isoprenoids synthesis. In the present study, we elucidate the contribution of these pathways in alpha-secretase activation. We demonstrate that zaragozic acid, a potent inhibitor of squalene synthase which blocks cholesterol synthesis but allows synthesis of isoprenoids, also stimulates alpha-secretase activity. Treatment of human n…

Central functional response to the novel peptide cannabinoid, hemopressin.

2013

Hemopressin is the first peptide ligand to be described for the CB₁ cannabinoid receptor. Hemopressin acts as an inverse agonist in vivo and can cross the blood-brain barrier to both inhibit appetite and induce antinociception. Despite being highly effective, synthetic CB₁ inverse agonists are limited therapeutically due to unwanted, over dampening of central reward pathways. However, hemopressin appears to have its effect on appetite by affecting satiety rather than reward, suggesting an alternative mode of action which might avoid adverse side effects. Here, to resolve the neuronal circuitry mediating hemopressin's actions, we have combined blood-oxygen-level-dependent, pharmacological-ch…

Intérêt du growth differentiation factor 15 (GDF15) comme biomarqueur pronostique après la survenue d'un Accident Vasculaire Cérébral ischémique (AVC)

2018

Introduction Le GDF15 est un biomarqueur de mauvais pronostic dans certaines pathologies cardiovasculaires comme le syndrome coronarien aigu. Son interet dans le domaine de AVC n’a ete que peu etudie a ce jour. Objectifs Notre travail consistait a l’evaluation des taux de GDF15 chez des patients hospitalises a la phase aigue d’un AVC ischemique traites par fibrinolyse et/ou thrombectomie. L’objectif principal etait d’evaluer l’association entre les taux de GDF15 et la recuperation fonctionnelle a 3 mois. Methodes Au total, 174 patients ont ete inclus entre le 16/01 et le 30/09/2017. Le consentement etait recueilli oralement. Des prelevements biologiques ont ete realises a l’admission du pat…

Impact of t-PA administration on brain BDNF levels in physiological conditions and in circulating BDNF levels in ischemic conditions : Human and anim…

2014

Our objective was to test the hypothesis that the beneficial effect of the administration of the recombinant form of tissue plasminogen activator (rt-PA) in ischemic stroke patient not only results from its fibrinolytic activity but also from its ability to increase brain-derived neurotrophic factor (BDNF) in the brain. To this end, we conducted an initial study to evaluate the effect of rt-PA on brain BDNF levels in healthy animals. In a second study, we investigated the effect of rt-PA on serum BDNF levels in ischemic stroke patients and in animals subjected to permanent focal cerebral ischemia. Blood samples were obtained from patient on admission (D0), D1, D7 and D90 after stroke and in…