Search results for "Synaptic plasticity"
showing 10 items of 132 documents
Proneurotrophin Binding to P75 Neurotrophin Receptor (P75ntr) Is Essential for Brain Lesion Formation and Functional Impairment after Experimental Tr…
2015
Traumatic brain injury (TBI) initiates an excessive mediator release of e.g. neurotrophins, which promote neuronal survival, differentiation, and modulate synaptic plasticity. Paradoxically, mature forms of neurotrophins promote neuronal survival, whereas unprocessed forms of neurotrophins induce cell death through p75 neurotrophin receptor (p75NTR) signaling. p75NTR is widely expressed during synaptogenesis and is subsequently downregulated in adulthood. Repair mechanisms after acute cerebral insults can reactivate its expression. Therefore, the influence of p75NTR on secondary brain damage was addressed. mRNA levels of p75NTR and its ligands were quantified in brain tissue up to 7 days af…
Proteomic signature of the Dravet syndrome in the genetic Scn1a-A1783V mouse model.
2021
Abstract Background Dravet syndrome is a rare, severe pediatric epileptic encephalopathy associated with intellectual and motor disabilities. Proteomic profiling in a mouse model of Dravet syndrome can provide information about the molecular consequences of the genetic deficiency and about pathophysiological mechanisms developing during the disease course. Methods A knock-in mouse model of Dravet syndrome with Scn1a haploinsufficiency was used for whole proteome, seizure, and behavioral analysis. Hippocampal tissue was dissected from two- (prior to epilepsy manifestation) and four- (following epilepsy manifestation) week-old male mice and analyzed using LC-MS/MS with label-free quantificati…
Short-term adaptation of conditioned fear responses through endocannabinoid signaling in the central amygdala
2010
International audience; Both, the cannabinoid receptor type 1 (CB1) and the central nucleus of the amygdala (CeA) are known to play crucial roles in the processing of fear and anxiety, whereby they appear to be especially involved in the control of fear states. However, in contrast to many other brain regions including the cortical subregions of the amygdala, the existence of CB1 in the CeA remains enigmatic. Here we show that CB1 is expressed in the CeA of mice and that CB1 in the CeA mediates short-term synaptic plasticity, namely depolarization-induced suppression of excitation (DSE) and inhibition (DSI). Moreover, the CB1 antagonist AM251 increased both excitatory and inhibitory postsyn…
Mouse photoreceptor synaptic ribbons lose and regain material in response to illumination changes
2004
Abstract Chemical synapses equipped with ribbons are tonically active, high-output synapses. The ribbons may play a role in the trafficking of synaptic vesicles. Recent findings in retinal rod cells of BALB/c mice indicate that ribbons are large and smooth in the dark phase, and, due to the formation and release of protrusions, small during the light phase. As a consequence of these changes, ribbons may traffick fewer vesicles in the light than in the dark phases. The aim of the present study was to find out whether the above ribbon changes in this mouse strain are strictly illumination-dependent and which signalling processes may be involved. Here, we show that ribbons form protrusions and…
Hippocampal ripple-contingent training accelerates trace eyeblink conditioning and retards extinction in rabbits.
2010
There are at least two distinct oscillatory states of the hippocampus that are related to distinct behavioral patterns. Theta (4–12 Hz) oscillation has been suggested to indicate selective attention during which the animal concentrates on some features of the environment while suppressing reactivity to others. In contrast, sharp-wave ripples (∼200 Hz) can be seen in a state in which the hippocampus is at its most responsive to any kind of afferent stimulation. In addition, external stimulation tends to evoke and reset theta oscillation, the phase of which has been shown to modulate synaptic plasticity in the hippocampus. Theoretically, training on a hippocampus-dependent learning task conti…
Role of mTOR-regulated autophagy in spine pruning defects and memory impairments induced by binge-like ethanol treatment in adolescent mice.
2021
Abstract Adolescence is a brain maturation developmental period during which remodeling and changes in synaptic plasticity and neural connectivity take place in some brain regions. Different mechanism participates in adolescent brain maturation, including autophagy that plays a role in synaptic development and plasticity. Alcohol is a neurotoxic compound and its abuse in adolescence induces neuroinflammation, synaptic and myelin alterations, neural damage and behavioral impairments. Changes in synaptic plasticity and its regulation by mTOR have also been suggested to play a role in the behavioral dysfunction of binge ethanol drinking in adolescence. Therefore, by considering the critical ro…
Behavioural parameters in aged rats are related to LTP and gene expression of ChAT and NMDA-NR2 subunits in the striatum.
2004
Striatal parameters were assessed for their relevance to age-related behavioural decline. Forty aged rats (28-30 months) were tested in the water maze and open field. Of these, seven superior and seven inferior learners were compared with each other in terms of levels of in vitro short- and long-term potentiation (STP and LTP), and gene expression of choline acetyltransferase (ChAT) as well as of the NMDA-NR2A-C subunits assessed by quantitative RT-PCR. Results revealed that the superior as compared with the inferior learners had higher levels of ChAT mRNA in the striatum. For the superior group, ChAT mRNA was correlated with escape on to the cued platform in the water maze, whereas level o…
Carnitine congener mildronate protects against stress- and haloperidol-induced impairment in memory and brain protein expression in rats.
2014
The present study investigates the efficacy of mildronate, a carnitine congener, to protect stress and haloperidol-induced impairment of memory in rats and the expression of brain protein biomarkers involved in synaptic plasticity, such as brain-derived neurotrophic factor (BDNF), acetylcholine esterase and glutamate decarboxylase 67 (GAD67). Two amnesia models were used: 2h immobilization stress and 3-week haloperidol treatment. Stress caused memory impairment in the passive avoidance test and induced a significant 2-fold BDNF elevation in hippocampal and striatal tissues that was completely inhibited by mildronate. Mildronate decreased the level of GAD67 (but not acetylcholine esterase) e…
Platelet-activating factor contributes to the induction of long-term potentiation in the rat somatosensory cortex in vitro
2007
The contribution of platelet-activating factor (PAF) to the induction of neocortical LTP was examined in rat brain slices containing the primary somatosensory cortex (SI). Field potentials evoked by single pulse stimulation in cortical layer IV were recorded from layer II/III. In control experiments, tetanic high frequency stimulation (HFS) resulted in input-specific, NMDA receptor-dependent LTP (21.1+/-3.2%; mean+/-SEM; n=15; P0.001). BN-52021 (5 microM), an antagonist at the extracellular PAF receptor, weakened the HFS-induced LTP to 12.4+/-2.7% (n=11; P0.05). In contrast, HFS-induced LTP was significantly enhanced to 29.4+/-2.3% (n=11; P0.05) when brain slices were superfused with ACSF c…
Alterations in the Hippocampal Endocannabinoid System in Diet-Induced Obese Mice
2010
The endocannabinoid (eCB) system plays central roles in the regulation of food intake and energy expenditure. Its alteration in activity contributes to the development and maintenance of obesity. Stimulation of the cannabinoid receptor type 1 (CB1receptor) increases feeding, enhances reward aspects of eating, and promotes lipogenesis, whereas its blockade decreases appetite, sustains weight loss, increases insulin sensitivity, and alleviates dysregulation of lipid metabolism. The hypothesis has been put forward that the eCB system is overactive in obesity. Hippocampal circuits are not directly involved in the neuronal control of food intake and appetite, but they play important roles in hed…