Search results for "exploratory behavior"
showing 10 items of 101 documents
High novelty-seeking predicts greater sensitivity to the conditioned rewarding effects of cocaine
2011
Novelty-seeking in rodents, defined as enhanced specific exploration of novel situations, is considered to predict the response of animals to drugs of abuse and, thus, identify "drug-vulnerable" individuals. The main objective of this work was to determine the capacity of two animal models-the novel object recognition task and the novel environment test-for evaluating to what extent novelty-seeking can predict greater sensitivity to the rewarding properties of cocaine in young adult (PND 56) and adolescent (PND 35) OF1 mice of both sexes. Conditioned place preference, a useful tool for evaluating the sensitivity of individuals to the incentive properties of addictive drugs, was induced with…
Behavioral impact of experience based on environmental enrichment: Influence of age and duration of exposure in male NMRI mice
2020
Prior studies have suggested that short periods of exposure to environmental enrichment (EE) in rodents induce physiological and behavioral effects. In the present study, our aim was to evaluate if the impact of experiences based on EE could be modulated by the age of onset and the developmental period of exposure. NMRI male mice (n = 64) were exposed to EE or standard environment (SE) and behavioral changes (anxiety, exploration, memory and social interaction) were evaluated. Groups compared were: (a) SE: exposure to SE on post-natal day (PND) 28 and lasting 6 months; (b) EE-6: exposure to EE on PND 28 and lasting 6 months; (c) EE-4: exposure to EE on PND 91 and lasting 4 months; (d) EE-2:…
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…
Attraction to male pheromones and sexual behaviour show different regulatory mechanisms in female mice.
2004
In rodents, female sexual behaviour is under hormonal control. The attraction females show for male-derived nonvolatile chemicals (pheromones) can be regarded as the first step of this behaviour, but it is unknown whether this attraction is also modulated by sexual steroids. To test this possibility, ovariectomized adult female mice with no experience of chemical signals from adult males were randomly assigned to four groups that received oil (control), progesterone, estradiol (E) or estradiol+progesterone (E+P) injections, respectively. Females were then tested for their attraction to male-soiled bedding and, subsequently, for their proceptive behaviour when confronted to adult males. Fema…
Effects of fluoxetine on behavioral deficits evoked by chronic social stress in rats.
2006
Recently, we described an advanced model of chronic social stress in male rats based on the resident intruder paradigm. In this model, rats subjected to daily social stress for 5 weeks showed behavioral changes resembling anhedonia and motivational deficits in humans. In the present study, male Wistar rats were subjected to 5 weeks of daily social defeat by an aggressive conspecific and concomitant treatment with the antidepressant drug fluoxetine (10 mg/kg) after the first week of stress. Compared with controls, rats exposed to chronic stress had significantly reduced locomotor and exploratory activity (rearing and sniffing) and diminished preference for sucrose solution. These effects wer…
Prenatal cocaine alters later responses to morphine in adult male mice.
2006
Mice prenatally exposed to cocaine (25 mg/kg), physiological saline or non-treated during the last 6 days of pregnancy were evaluated as adults for the rewarding properties of 2 mg/kg of morphine, using the conditioned place preference (CPP) procedure. Likewise, isolated animals underwent a social interaction test with conspecifics after receiving the same morphine dose. Unlike control or animals pre-treated with saline, subjects prenatally treated with cocaine did not develop CPP with this dose of morphine. Only cocaine-exposed animals showed increased threat, avoidance and fleeing during the social encounter. No differences in motor effects of morphine were observed. Analysis of monoamine…
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…
The effects of different basal levels of anxiety on the behavioral shift analyzed in the central platform of the elevated plus maze.
2015
The aim of the present research was to study the effects of different basal levels of anxiety on the behavioral shift studied in the central platform of the elevated plus maze. To this purpose, quantitative and multivariate analyses, the latter based on transition matrix elaboration, were carried out on Wistar and on DA/Han rats the latter belonging to a strain characterized by different reactivity to anxiogenic stimuli. Wistar rats spent 74.11 ± 5.11 s in the central platform, whereas DA/Han significantly more: 127.08 ± 9.87. Per cent distributions evidenced a clear-cut difference in walking activities (46.25% in Wistar, 28.4% in DA/Han rats) and in the sniffing activities (45.82% in Wista…
The novelty-seeking phenotype modulates the long-lasting effects of adolescent MDMA exposure.
2015
Exposure to drugs such as ethanol or cocaine during adolescence induces alterations in the central nervous system that are modulated by the novelty-seeking trait. Our aim was to evaluate the influence of this trait on the long-term effects of MDMA administration during adolescence on spontaneous behavior and conditioned rewarding effects in adulthood. Adolescent mice were classified as high or low novelty seekers (HNS or LNS) according to the hole-board test and received either MDMA (0, 10 or 20mg/kg PND 33-42) or saline. Three weeks later, having entered adulthood (PND>68), one set of mice performed the elevated plus maze and social interaction tests, while another set performed the condit…
Cerebral embolic ischemia in rats: correlation of stroke severity and functional deficit as important outcome parameter.
2006
The embolic MCA occlusion model in rats is used for recanalisation studies in acute stroke. In addition to the determination of lesion size, the assessment of functional outcome may improve the value of this model. Male Wistar rats were submitted to MCA clot embolism or sham surgery. In order to achieve a larger variety of lesion volume, 2 subgroups (each 7 animals) were subjected to differently sized emboli (30 and 40 mm). Follow-up period was 6 days. Outcome assessment consisted of a test battery including parallel bar crossing, observation of behaviour in an open field and an 8-arm maze and a neurological score with ten different sensorimotor and coordinative items. Animals were perfusio…