Search results for "Ley"
showing 10 items of 1218 documents
The Polysialylated Form of the Neural Cell Adhesion Molecule (PSA-NCAM) Is Expressed in a Subpopulation of Mature Cortical Interneurons Characterized…
2010
Principal neurons in the adult cerebral cortex undergo synaptic, dendritic, and spine remodeling in response to different stimuli, and several reports have demonstrated that the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) participates in these plastic processes. However, there is only limited information on the expression of this molecule on interneurons and on its role in the structural plasticity of these cells. We have found that PSA-NCAM is expressed in mature interneurons widely distributed in all the extension of the cerebral cortex and have excluded the expression of this molecule in most principal cells. Although PSA-NCAM expression is generally considered a …
Effects of a single-dose hypertonic saline hydroxyethyl starch on cerebral blood flow, long-term outcome, neurogenesis, and neuronal survival after c…
2012
The beneficial effects of hypertonic saline on neuronal survival and on cerebral blood flow have been shown in several animal models of global and focal brain ischemia. Because of the potential benefits of hypertonic solutions, it is hypothesized that hydroxyethyl starch enhances cerebral blood flow and improves long-term outcome after cardiac arrest and cardiopulmonary resuscitation in an animal model.Laboratory animal study.University animal research laboratory.Fifty-nine male Sprague-Dawley rats.Rats were randomized to receive either 7.2% saline/6% hypertonic saline hydroxyethyl starch (4 mL/kg) or vehicle (NaCl 0.9 %) after 9 mins of asphyxic cardiac arrest and cardiopulmonary resuscita…
Effects of chronic fluoxetine treatment on the rat somatosensory cortex: Activation and induction of neuronal structural plasticity
2009
Recent hypotheses support the idea that disruption of normal neuronal plasticity mechanisms underlies depression and other psychiatric disorders, and that antidepressant treatment may counteract these changes. In a previous report we found that chronic fluoxetine treatment increases the expression of the polysialylated form of the neural cell adhesion molecule (PSA-NCAM), a molecule involved in neuronal structural plasticity, in the somatosensory cortex. In the present study we intended to find whether, in fact, cell activation and neuronal structural remodeling occur in parallel to changes in the expression of this molecule. Using immunohistochemistry, we found that chronic fluoxetine trea…
PSA-NCAM expression in the rat medial prefrontal cortex
2005
The rat medial prefrontal cortex, an area considered homologous to the human prefrontal cortex, is a region in which neuronal structural plasticity has been described during adulthood. Some plastic processes such as neurite outgrowth and synaptogenesis are known to be regulated by the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). Since PSA-NCAM is present in regions of the adult CNS which are undergoing structural remodeling, such as the hypothalamus or the hippocampus, we have analyzed the expression of this molecule in the medial prefrontal cortex of adult rats using immunohistochemistry. PSA-NCAM immunoreactivity was found both in cell bodies and in the neuropil of…
Nicotinamide exerts different acute effects on microcirculatory function and tissue oxygenation in rat tumors
1993
Abstract Purpose : Nicotinamide has been reported to preferentially radiosensitize tumor tissue, supposedly through a reduction in tumor hypoxia. This may occur as a result of nicotinamide-induced changes in tumor blood flow and therefore the present study was undertaken to evaluate the effect of nicotinamide on circulatory parameters in skeletal muscle and tumor tissue (subcutaneously-implanted DS-sarcomas) of the rat. Methods and Materials : Mean arterial blood pressure (measured in the common carotid artery using a pressure transducer) and red blood cell flux (as measured by laser Doppler flowmetry) were continuously monitored for 120 min following a single intraperitoneal application of…
Critical role of nitric oxide on nicotine-induced hyperactivation of dopaminergic nigrostriatal system: electrophysiological and neurochemical eviden…
2010
Nicotine, the main psychoactive ingredient in tobacco, stimulates dopamine (DA) function, increasing DA neuronal activity and DA release. DA is involved in both motor control and in the rewarding and reinforcing effects of nicotine; however, the complete understanding of its molecular mechanisms is yet to be attained. Substantial evidence indicates that the reinforcing properties of drugs of abuse, including nicotine, can be affected by the nitric oxide (NO) system, which may act by modulating central dopaminergic function. In this study, using single cell recordings in vivo coupled with microiontophoresis and microdialysis in freely moving animals, the role of NO signaling on the hyperacti…
Modulatory role of acetylcholine in the rat pineal gland
1998
Abstract The function of acetylcholine (ACh) in the mammalian pineal gland is unknown. To test the hypothesis that ACh exerts a modulatory role in this organ, in the present study electrophysiogical multiunit recordings were carried out in ex-vivo rat pineal glands superfused with different drugs. It was found that ACh (10 −7 M) as well as the cholinergic agonists oxotremorine (10 −7 M) and nicotine (10 −6 M) increased the discharge rates of most of the spontaneously active units and led to burst activity in previously regularly firing cells. It is concluded that ACh may play a modulatory role in the pineal by influencing the firing of a special population of pineal cells with perhaps recep…
Effects of chronic nicotine on the temporal structure of anxiety-related behavior in rats tested in hole-board.
2019
Abstract The present study aimed to assess the behavioral effects of chronic treatments of different doses of nicotine by using both quantitative and multivariate T-pattern analysis (TPA), which can reveal hidden behavioral structures, in Sprague-Dawley rats tested in the hole-board apparatus. To this purpose, nicotine ditartrate was administered at the doses of 0.1, 0.5 and 1 mg/kg i.p., three times per day, for 14 consecutive days. As to quantitative evaluations, we observed significant reductions in the mean durations and mean frequencies of walking, climbing, immobile-sniffing and rearing in comparison to control. A significant reduction of edge-sniff and head-dip mean frequencies was a…
Nicotine modulation of the lateral habenula/ventral tegmental area circuit dynamics: An electrophysiological study in rats
2022
Abstract Nicotine, the addictive component of tobacco, has bivalent rewarding and aversive properties. Recently, the lateral habenula (LHb), a structure that controls ventral tegmental area (VTA) dopamine (DA) function, has attracted attention as it is potentially involved in the aversive properties of drugs of abuse. Hitherto, the LHb-modulation of nicotine-induced VTA neuronal activity in vivo is unknown. Using standard single-extracellular recording in anesthetized rats, we observed that intravenous administration of nicotine hydrogen tartrate (25–800 μg/kg i.v.) caused a dose-dependent increase in the basal firing rate of the LHb neurons of nicotine-naive rats. This effect underwent com…
Regulation of α4β2α5 nicotinic acetylcholinergic receptors in rat cerebral cortex in early and late adolescence: Sex differences in response to chron…
2013
Chronic nicotine administration in animals, and smoking in humans, causes up-regulation of α4β2* neuronal nicotinic receptors (nAChRs), which has been hypothesized to contribute to the addictive actions of nicotine. We used a rat model to test whether such up-regulatory effects differ in adolescents versus adults, and in males versus females. Following chronic treatment with nicotine or saline via subcutaneous osmotic minipumps, we measured α4β2 and α4β2α5 nAChRs in cerebral cortex using [3H]epibatidine to label assembled nAChRs, and selective antibodies to measure the individual subunits via immunoprecipitation. For the first time, we provide a detailed characterization of the response of …