Search results for "disease model"

Experimental Models of Autoimmune Hepatitis

1991

Effects of several degrees of chronic social defeat stress on emotional and spatial memory in CD1 mice

2015

In the present study, the effects of several degrees of CSDS (Chronic Social Defeat Stress) on emotional and spatial memory in mice were evaluated in separate experiments. Male CD1 mice were randomly assigned to four experimental groups (n=10-12) for each experiment: NS (non-stressed), S5, S10 and S20 (5, 10 and 20 sessions of CSDS, respectively). The S groups underwent the corresponding number of agonistic encounters (10min each) over a 20-day period. 24h after the last session of CSDS, mice performed the inhibitory avoidance (Experiment 1) or the Morris water maze test (Experiment 2). In both experiments, animals were also evaluated in the elevated plus maze for 5min to obtain complementa…

'Up-regulation of histone acetylation induced by social defeat mediates the conditioned rewarding effects of cocaine

2016

Social defeat (SD) induces a long-lasting increase in the rewarding effects of psychostimulants measured using the self-administration and conditioned place procedures (CPP). However, little is known about the epigenetic changes induced by social stress and about their role in the increased response to the rewarding effects of psychostimulants. Considering that histone acetylation regulates transcriptional activity and contributes to drug-induced behavioral changes, we addressed the hypothesis that SD induces transcriptional changes by histone modifications associated with the acquisition of place conditioning. After a fourth defeat, H3(K9) acetylation was decreased in the hippocampus, whil…

Inhibitory avoidance learning in CD1 mice: Effects of chronic social defeat stress

2015

Chronic social defeat stress (CSDS) is an animal model widely used to determine the neurobiological mechanisms of stress and its associated pathologies. In this study, the effects of CSDS on inhibitory avoidance (IA) were evaluated in post-pubertal and adult male CD1 mice, instead of the C57BL/6J strain used in the CSDS standard protocol. CSDS consisted of daily 5-min (experiments 1 and 2) or 10-min (experiment 3) agonistic encounters on 21 consecutive days. Twenty four hours after the last session of CSDS, all the mice were tested for IA. They were also evaluated in an elevated plus-maze, obtaining complementary measures of locomotor activity and emotionality. In experiments 1 and 2, IA le…

Enhanced habit-based learning and decreased neurogenesis in the adult hippocampus in a murine model of chronic social stress

2009

Abstract Stress can induce preferential engagement of habit learning mediated by the basal ganglia, relative to learning that involves complex spatial associations contributed by the hippocampal formation. We explored in mice the influence that chronic episodes of social stress exert on the selection of cognitive/spatial vs. habit-based learning strategies. Male mice were exposed to repeated episodes of social confrontation and were categorized as dominant, subordinate or undetermined according to quantitative ethologically relevant parameters of aggression. Mice were then trained in a conditional discrimination task in the T-maze in the presence of allocentric cues until five correct choic…

Cognitive and behavioural effects induced by social stress plus MDMA administration in mice

2017

Adverse life experiences such as social stress may make an individual more vulnerable to drug addiction and mental disorders associated with drug consumption. The present work aimed to evaluate the effects of stress induced by acute social defeat combined with the administration of 3,4-methylenedioxymethamphetamine (MDMA) on depression-like behaviour, memory function and motor response to drug in late adolescent male mice. Two groups of mice were exposed to social defeat (SD) during four encounters with an aggressive co-specific, which took place on alternate days. Immediately after defeat, animals were treated with saline or MDMA 10mg/kg (SD+SAL and SD+MDMA). In control groups, mice were p…

Dual roles of Aβ in proliferative processes in an amyloidogenic model of Alzheimer’s disease

2017

Alzheimer’s disease is a major neurodegenerative disorder that leads to severe cognitive deficits in the elderly population. Over the past two decades, multiple studies have focused on elucidating the causative factors underlying memory defects in Alzheimer’s patients. In this regard, new evidence linking Alzheimer’s disease-related pathology and neuronal stem cells suggests that hippocampal neurogenesis impairment is an important factor underlying these cognitive deficits. However, because of conflicting results, the impact of Aβ pathology on neurogenesis/gliogenesis remains unclear. Here, we investigated the effect of Aβ on neuronal and glial proliferation by using an APP/PS1 transgenic m…

Spontaneous Epileptic Manifestations in a DCX Knockdown Model of Human Double Cortex

2010

Previous reports indicate that in utero knockdown of doublecortin (DCX) results in the genesis of a subcortical heterotopia reminiscent of the doublecortex observed in female patients with DCX mutations. It has also been shown that these rats display an increased susceptibility to convulsant agents and increased cortical neurons excitability; but it is presently unknown whether they display spontaneous seizures. Furthermore, the link between the size of heterotopia and the clinical manifestation remained to be elucidated. Using video--electrocorticogram recordings, we now report that DCX knockdown induces frequent spontaneous seizures commonly associated with myoclonic jerks in adult rats. …

Chronic cocaine exposure impairs progenitor proliferation but spares survival and maturation of neural precursors in adult rat dentate gyrus

2006

Recent observations indicate that drugs of abuse, including alcohol and opiates, impair adult neurogenesis in the hippocampus. We have studied in rats the impact of cocaine treatment (20 mg/kg, daily, i.p.) on cell proliferation, survival and maturation following short-term (8-day) and long-term (24-day) exposure. Using 5'-bromo-2-deoxyuridine (BrdU) and Ki-67 as mitotic markers at the end of the drug treatments, we found that both short- and long-term cocaine exposures significantly reduced cell proliferation in the dentate gyrus (DG) of the hippocampus. By labelling mitotic cells with BrdU pulses before or during the early stages of the drug treatment, we determined that long-term cocaine…

Subventricular Zone-Derived Neuroblasts Migrate and Differentiate into Mature Neurons in the Post-Stroke Adult Striatum

2006

Recent studies have revealed that the adult mammalian brain has the capacity to regenerate some neurons after various insults. However, the precise mechanism of insult-induced neurogenesis has not been demonstrated. In the normal brain, GFAP-expressing cells in the subventricular zone (SVZ) of the lateral ventricles include a neurogenic cell population that gives rise to olfactory bulb neurons only. Herein, we report evidence that, after a stroke, these cells are capable of producing new neurons outside the olfactory bulbs. SVZ GFAP-expressing cells labeled by a cell-type-specific viral infection method were found to generate neuroblasts that migrated toward the injured striatum after middl…