Search results for "nicotine"
showing 10 items of 145 documents
A specific anti-aggressive effect of repeatedly administered lobeline.
2002
The effects of chronic treatments with nicotinic agonists on agonistic encounters have received little attention. The effects of repeated (for 10 days) SC administration of (-)-lobeline (9.3, 18.6 and 37.2 micromol/kg) and (-)-nicotine (0.93, 1.86 and 3.72 micromol/kg) were evaluated using the mouse isolation-induced aggression model. Individually housed OF1 male mice served as experimental animals and were confronted by 'standard opponents'. Each mouse was tested only once on the last day of the repeated drug treatment. Videotaped agonistic encounters were analysed estimating the times allocated to 11 behavioural categories. Repeated treatment with the highest dose of lobeline diminished a…
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 housing and nicotine on shuttle-box avoidance in male NMRI mice
2005
The present study aimed to evaluate whether housing condition could interact with nicotine administration in influencing the acquisition of a two-way active avoidance task. Male NMRI mice were either group- or individually housed for 30 days and, after this period, evaluated both in the actimeter and, 24h later, in the elevated plus-maze. On the basis of the percentage of time spent in the open arms of the plus-maze, both group- and individually housed mice were sub-classified into three groups with high, moderate or low anxiety baseline levels. Effects of nicotine on the acquisition of the two-way active avoidance task was assessed in each of these groups of mice using an automated shuttle…
Nicotinic and muscarinic modulation of 5-hydroxytryptamine (5-HT) release from porcine and canine small intestine
1992
Strips of porcine and canine small intestine were incubated in vitro and the release of 5-hydroxytryptamine (5-HT) was determined by HPLC with electrochemical detection. The spontaneous outflow of 5-HT from the porcine and canine small intestine largely reflects calcium-dependent 5-HT secretion from enterochromaffin cells which are under a spontaneous neuronal, excitatory input as indicated by the inhibitory effect (30-40%) of tetrodotoxin. In both species, nicotine enhanced the release of 5-HT in a concentration-dependent manner by a maximum of about 50% at 100 microM. This effect was blocked by the nicotine receptor antagonist hexamethonium, but not by the subtype-selective nicotine 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…
Acute intermittent nicotine treatment induces fibroblast growth factor-2 in the subventricular zone of the adult rat brain and enhances neuronal prec…
2007
Abstract Over the past years, evidence has accumulated that stem cells are present in the adult brain, and generate neurons and/or glia from two active germinal zones: the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. This study shows that acute intermittent nicotine treatment significantly enhances neuronal precursor cell proliferation in the SVZ of adult rat brain, but not in the SGZ of the hippocampus, and pre-treatment with mecamylamine, a nonselective nAChR antagonist, blocks the enhanced precursor proliferation by nicotine. This effect is supported by up-regulation of fibroblast growth factor-2 (FGF-2) mRNA …
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…
Spatial learning in male mice with different levels of aggressiveness: effects of housing conditions and nicotine administration
2003
The main aim of the present investigation was to evaluate the possible modulation of spatial learning ability by housing conditions and level of aggressiveness in mice, also testing whether differences in locomotion and anxiety could influence this relationship. Additionally, we have examined effects of nicotine in the acquisition and retention of a spatial learning task in groups of mice differing in these variables. NMRI male mice were either group-housed or individually housed for 30 days and then classified into mice with short (SAL) and long (LAL) attack latency after a pre-screening agonistic encounter. Locomotor activity and baseline levels of anxiety of these groups were evaluated i…
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 …
Nicotinic drugs and postganglionic sympathetic transmission
1970
1. Isolated rabbit hearts with the sympathetic nerves attached were perfused with Tyrode solution. The noradrenaline output into the perfusate was measured fluorimetrioally. 2. When the niootinic autoinhibition produced by infusions of nicotine, DMPP, or acetylcholine (in the presence of atropine) was fully developed, the output of noradrenaline evoked by electrical stimulation of the postganglionic sympathetic nerves was not depressed. 3. Acetylcholine in the presence of atropine produced a transitory facilitation of the noradrenaline output evoked by sympathetic nerve stimulation. 4. Prolonged infusion of DMPP caused an adrenergic neurone block which was not observed after nicotine, or ac…