Search results for "HIPPOCAMPUS"
showing 10 items of 622 documents
Role of interleukin-6 and soluble IL-6 receptor in region-specific induction of astrocytic differentiation and neurotrophin expression.
1999
Increasing evidence supports an essential role for interleukin-6 (IL-6) in the development, differentiation, as well as de- and re-generation of neurons in the central nervous system (CNS). Both IL-6 and its specific receptor (IL-6R) are expressed on neurons and glial cells including astrocytes. In this study, we have analyzed the responses of primary rat astrocytes of various brain regions to IL-6 with respect to morphological changes and neurotrophin expression. Since IL-6 alone failed to initiate effects on astrocytes, we have examined whether the soluble IL-6R (sIL-6R) can modulate the responsiveness of to IL-6 in these cells. For this purpose, we used a highly active fusion protein of …
Age-related changes in the regulation of transcription factor NF-kappa B in rat brain.
1997
Aging process involves an increase in stress at cellular level. We studied whether aging affects the regulation of stress responsive transcription factor NF-kappa B in brain samples of Wistar rats. Hippocampus, cerebellum, and temporal and frontal lobes of cortex were studied. We observed a significant up-regulation in the constitutive, nucleus-located NF-kappa B binding activity in 30-month-old Wistar rats compared to young and 18-month-old rats. The increase was most prominent in cerebellum and in frontal cortex, but age-related changes did not occur in hippocampus. Inducible, cytoplasmic NF-kappa B binding activity was not affected by aging in any of the samples studied. Western blot ass…
Nicotine-induced FGF-2 mRNA in rat brain is preserved during aging
2004
Indirect trophic actions of nicotine on brain during aging are suggested from observations describing nicotine as a cognitive enhancer, increasing vigilance and improving learning and memory, and both in vitro and in vivo models have demonstrated neuroprotective effects of nAChR agonists. Previously, we have reported that an acute intermittent (-)nicotine treatment significantly increases fibroblast growth factor-2 (FGF-2) mRNA and protein in several brain regions of rat brain. The present study was designed to analyse if nicotine-induced FGF-2 expression in the rat brain was preserved during aging. Using in situ hybridization and quantitative RNase protection assay the present paper report…
Minireview: Nicotinic Acetylcholine Receptors on Hippocampal Neurons: Distribution on the Neuronal Surface and Modulation of Receptor Activity
1997
The recent development of a technique that uses infrared microscopy for the visualization of well-defined areas on the surface of neurons, and a computerized system of micromanipulators led to the discovery that functional nicotinic acetylcholine receptors (nAChRs) are expressed at higher density on the dendrites than on the soma of rat hippocampal neurons. The finding that the expression of alpha-bungarotoxin-sensitive, alpha 7-bearing, nAChRs and dihydro-beta-erythroidine-sensitive, alpha 4 beta 2 nAChRs tends to increase along the dendritic length suggests that these receptors may be highly involved in the integration of synaptic functions in hippocampal neurons. The present report also …
Antidepressants are functional antagonists at the serotonin type 3 (5-HT3) receptor
2003
Antidepressants are commonly supposed to enhance serotonergic and/or noradrenergic neurotransmission by inhibition of neurotransmitter reuptake through binding to the respective neurotransmitter transporters or through inhibition of the monoamine oxidase. Using the concentration-clamp technique and measurements of intracellular Ca2+, we demonstrate that different classes of antidepressants act as functional antagonists at the human 5-HT3A receptor stably expressed in HEK 293 cells and at endogenous 5-HT3 receptors of rat hippocampal neurons and N1E-115 neuroblastoma cells. The tricyclic antidepressants desipramine, imipramine, and trimipramine, the serotonin reuptake inhibitor fluoxetine, t…
The role of neurosteoids sulphate in a spatial and object recognition learning task
2012
The term “neuroactive steroid” refers to steroids that have rapid modulatory effects on ligand-gated ion channels via non-genomic mechanism. Specifically, neurosteroids can alter neuronal excitability via the cell surface interacting with specific neurotransmitter receptors. The neurosteroid pregnenolone sulphate (PREGS) has been described as negative modulator of GABAA receptor and positive modulator of NMDA receptor, affecting cognition as well as emotionality. The present study was aimed to assess the effects of the acute administration of PREGS (10 mg/Kg, s. c.) on rats cognitive functions using a novel task, the Can test. This task explores, under reinforcement, the spatial/visual cues…
Timoleonte e i centri indigeni della Sicilia centrale. L’apporto dell’evidenza numismatica
2011
The studies that in the 1960s developed the theme of the "revival of the Timoleontian age" in the inland centers of central-southern Sicily were based on the erroneous attribution to the Timoleontian age of the Syracusan coin series with the head of Athena/hippocampus and the head of Athena/ star between two dolphins, which determined the generic chronological lowering of the materials and archaeological structures with which the coins were associated and the consequent assignment of many archaeological evidences to the second half of the fourth century BC. The reinterpretation of the numismatic evidence from the hinterland of Sicily proposed in this study offers new interpretative perspect…
Segmentation automatique et analyse de forme d'hippocampes humains dans l'étude de la maladie d'Alzheimer
2011
The aim of this thesis is to investigate the shape change in hippocampus due to the atrophy in Alzheimer’s disease (AD). To this end, specific algorithms and methodologies were developed to segment the hippocampus from structural magnetic resonance (MR) images and model variations in its shape. We use a multi-atlas based segmentation propagation approach for the segmentation of hippocampus which has been shown to obtain accurate parcellation of brain structures. We developed a supervised method to build a population specific atlas database, by propagating the parcellations from a smaller generic atlas database. Well segmented images are inspected and added to the set of atlases, such that t…
Reservoir computing model of prefrontal cortex creates novel combinations of previous navigation sequences from hippocampal place-cell replay with sp…
2019
As rats learn to search for multiple sources of food or water in a complex environment, they generate increasingly efficient trajectories between reward sites. Such spatial navigation capacity involves the replay of hippocampal place-cells during awake states, generating small sequences of spatially related place-cell activity that we call “snippets”. These snippets occur primarily during sharp-wave-ripples (SWRs). Here we focus on the role of such replay events, as the animal is learning a traveling salesperson task (TSP) across multiple trials. We hypothesize that snippet replay generates synthetic data that can substantially expand and restructure the experience available and make learni…
Correction: Indomethacin blocks the increased conditioned rewarding effects of cocaine induced by repeated social defeat
2019
It is well established that repeated social defeat stress can induce negative long-term consequences such as increased anxiety-like behavior and enhances the reinforcing effect of psychostimulants in rodents. In the current study, we evaluated how the immune system may play a role in these long-term effects of stress. A total of 148 OF1 mice were divided into different experimental groups according to stress condition (exploration or social defeat) and pre-treatment (saline, 5 or 10 mg/kg of the anti-inflammatory indomethacin) before each social defeat or exploration episode. Three weeks after the last social defeat, anxiety was evaluated using an elevated plus maze paradigm. After this tes…