Search results for "agonistic behavior"
showing 9 items of 19 documents
Differential sensitivity to the effects of nicotine and bupropion in adolescent and adult male OF1 mice during social interaction tests.
2008
Few studies have compared the action of both nicotine (NIC) and bupropion (BUP), an antidepressant used to treat NIC dependence, on social and aggressive behavior at different ages. This study aims to determine whether these drugs produce differential effects in adolescent (postnatal day: 36–37) and adult (postnatal day: 65–66) mice that have been housed individually for 2 weeks in order to induce aggressive behavior. Mice received BUP (40, 20, or 10 mg/kg), NIC (1, 0.5, and 0.25 mg/kg as base), or vehicle earlier to a social interaction test. BUP (40 mg/kg) decreased social investigation and increased nonsocial exploration in both adolescent and adult mice. The same effects were also obser…
Haloperidol does not antagonize the effects of stress on aggressive behaviour in mice.
1990
The possibility that antipsychotic drugs antagonize the behavioural effects of stress on agonistic behaviour has been explored. Male mice of the OF.1 strain were subjected to the following treatments: 1) Immobilization stress (ten or twenty minutes in duration), 2) haloperidol (three doses) and 3) immobilization stress (ten minutes) plus haloperidol. Individually housed experimental animals confronted standard opponents (anosmic animals) in ten-minute encounters in a neutral cage. Encounters were videotaped and behaviour evaluated, assigning times allocated by subjects to eleven broad behavioural categories. The data show that stress markedly decreases attack behaviour, but haloperidol does…
Rewarding effects of 3,4-methylenedioxymethamphetamine (“Ecstasy”) in dominant and subordinate OF-1 mice in the place preference conditioning paradigm
2006
We tested the ability of 3,4-methylenedioxymethamphetamine (MDMA) to induce conditioned place preference (CPP) in dominant and subordinate OF-1 mice subjected to cohabitation and repeated sessions of agonistic confrontation, as well as in non-confronted mice. We selected doses of MDMA (2, 6, 10 mg/kg) previously reported to induce CPP in mice and we measured expression of c-Fos evoked by the treatments in non-confronted mice. MDMA induced c-Fos protein in several corticolimbic regions involved in drug-induced reward. Mice were exposed to brief sessions of agonistic confrontation on 5 consecutive days. Determinations of circulating hormones and drug conditioning tests were carried out on com…
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…
Development of tolerance to the antiaggressive effects of morphine
2001
Many reports have demonstrated that there is a development of tolerance to many effects produced by morphine. This study was conducted with the aim of determining whether the antiaggressive actions of morphine develop tolerance after chronic administration. Acute morphine administration produced antiaggressive effects which disappeared after chronic (7 days) treatment in isolated mice. An increase in non-social exploration was observed, representing morphine-induced hyperactivity, after acute treatment, which was not present after chronic administration. In conclusion, there is a development of tolerance to the antiaggressive and motor effects of morphine. Language: en
Environmental lighting and muricidal behaviour in the male Wistar rat.
1990
Effects of different conditions of environmental lighting on the appearance of the muricidal behaviour in male Wistar rats have been studied. The animals were kept under different conditions of environmental lighting: 1) natural day light alternated with the dark of the night; 2) sodium, continuous light emitted by a sodium steam lamp; 3) neon, continuous light emitted by fluorescent neon tubes. The continuous sodium steam light increased the percentage of animals becoming muricide when compared to animals bred in a natural environment with a normal succession of day-night lighting. On the contrary, this percentage decreased if the rats of the same group are exposed to continuous light emit…
Studies on effects of tamoxifen (ICI 46474) on agonistic encounters between pairs of intact mice.
1988
The anti-estrogen tamoxifen (Tam), which has been shown to dramatically suppress offensive behavior in male rats without markedly influencing other aspects of the social encounter, was tested for its effectiveness in mice. TO strain albino mice were given control injections or 50 or 100 micrograms of Tam for 4 or 8 days. Subsequently, mice were tested in pairs (for a particular dose and treatment duration) in which both animals received Tam, one animal received Tam and one saline, or both animals received saline control injections. Ten-minute videotaped encounters were analyzed in terms of total times allocated to nonsocial investigation, social investigation, offense, defense, sexual activ…
Antiaggressive and motor effects of haloperidol show different temporal patterns in the development of tolerance.
1993
Abstract The study of the temporal course of tolerance development was used as a means to separate different aspects of the action of haloperidol on social behavior. Agonistic behavior was studied in isolated male mice that confronted standard opponents (anosmic and grouped conspecifics) in a neutral area. The aggressive and motor behaviors of the experimental animals were evaluated 30 min or 24 h either after a single injection of haloperidol (0.4 mg/kg) or following the last of a series of 15 or 30 injections. When animals were evaluated 30 min after the haloperidol injection, no tolerance to the antiaggressive effects was evident. The action on immobility, on the contrary, showed a clear…
Changes in the structure of the agonistic behavior of mice produced by D-amphetamine.
1997
The effects of three acute doses of D-amphetamine (0.25, 1.5 and 3 mg/kg) were studied in a model of isolation-induced aggression in male mice. An ethopharmacological analysis of the encounters was carried out, which studied the frequency, total and mean duration of different behavioral categories, including the temporal distribution of attacks and the duration of inter-attack intervals. The results show a reduction in the total and mean duration of the Attack category and an increase in motor activity manifested by longer durations, both total and mean, of Non Social Exploration and shorter Immobility. The temporal analysis of Attack revealed an increase in the number of very short (< 15 s…