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At least 523 records · Page 29Linked to original sources
PubMed1997

Cholecystokinin receptors mediate the development of a preference for the mother by newly born lambs.

The aim of this study was to investigate the effect of selective cholecystokinin (CCK) antagonists on the development of a preference for the mother by newly born lambs. At birth lambs received an injection of the CCK-A antagonist devazepide (0.01 or 0.1 mg/kg), the CCK-B antagonist PD135158 (0.01 or 0.1 mg/kg), or saline for the controls (1 ml/kg). No major side effects were observed in the first 4 postnatal hours except that lambs receiving PD135158 displayed more exploratory behavior towards the maternal body than lambs from the other groups. When tested in a 2-choice test situation at 24 hr of age, lambs treated with PD135158 or saline spent significantly more time near their dams than near the alien ewes, whereas lambs treated with devazepide did not show any discrimination. The effect of devazepide persisted at 48 hr of age. The use of a CCK-A antagonist, but not a CCK-B antagonist, was concluded to prevent the formation of a preferential relationship between the lamb and its mother, most probably by impairing neonatal learning.

Animals↗
PubMed1982

Attention and habituation: odor preferences, long-term memory, and multiple sensory cues of novel stimuli.

Investigation of and habituation to novel stimuli are part of exploratory behavior of rodents. They are necessary for assessing the environment in seeking food and sexual partners and in avoiding predators. Male and female gerbils were tested in the stimulus-elicited investigation paradigm in order to address several questions on three issues: (a) Gerbils initially showed preferences for odors of strange male bedding and for odors of home cage bedding and then habituated. There was no preference between these two odors, although they could be discriminated. The complex odor stimulus elicited more response than any of the components tested. (b) Memory of an object or of an odor was demonstrated up to 4 wk later. (c) Sensory deprivation by blinding, anosmizing, or removing somatosensation of the upper snout made only small differences in investigation. The removal of any two of these sensory inputs produced more interference with the response, but all of the gerbils investigated the stimulus. It is concluded that attention to novelty and habituation after repeated exposure are very robust behaviors and are mediated through multiple sensory channels.

Animals↗
PubMed1982

A rat model of psychopathology for use in exercise science.

Exploratory behavior, defecation, urination, and a subjective psychophysical rating system were evaluated in a series of four experiments designed to assess rat psychopathology. In every case, individual rats were studied for 5-min periods in an open field consisting of 49 7.5-inch squares. We find that the open-field test can be scored in a highly objective manner (r = 0.93-0.98) by two observers. The reproducibility (r = 0.79-0.85) of the assessment using total squares traversed is not improved using any of the other parameters evaluated. Use of total squares alone was also found to be in agreement with a subjective behavioral rating procedure (r = 0.96-0.98). Fifty percent of overall variability occurs in a rat's first trial. Therefore, the average of total squares traversed on the second and third (not necessarily consecutive) days provides a reliable and objective index of a rat's emotional status. Using this criterion, we find that a random group of 30 adult, male Sprague-Dawley rats exhibit a range of psychopathologies. We propose that this method of assessment provides a rat model of emotionality which should theoretically be modifiable by experimental paradigms involving exercise and pharmacological or dietary intervention.

Animals↗
PubMed2006

Targeted in vivo expression of nicotinic acetylcholine receptors in mouse brain using lentiviral expression vectors.

Nicotinic acetylcholine receptors (nAChRs) in the brain exhibit diverse functional properties and ubiquitous distribution. Yet, except for providing a receptor for the exogenously applied nicotine of tobacco products, their role in the normal functioning of the brain has remained elusive. We have used a lentiviral expression vector to re-express the beta2 subunit specifically in the ventral tegmental area (VTA) of beta2-/- mice. The viral vector efficiently expresses beta2- subunit protein leading to new nAChR-binding sites. VTA neurons transduced by the lentiviral vector are responsive to intravenous nicotine when analyzed using in vivo electrophysiology. Nicotine-induced dopamine release from the nucleus accumbens (NuAcc) was also restored in re-expressing beta2-/- mice. Intra-VTA injection of nicotine was found to be reinforcing in both wild-type and beta2-subunit re-expressing beta2-/- mice, but not in beta2-/- mice. Furthermore, in the absence of applied nicotine, the spontaneous slow exploratory behavior of the mice was restored, whereas fast navigation did not change. This latter behavioral analysis suggests a role for beta2* nAChR, specifically expressed in the VTA, in mammalian cognitive function.

Animals↗
PubMed2000

Personality types and suicidal behavior: an exploratory study.

This study used cluster analysis to explore prominent personality traits among a sample of suicidal psychiatric patients (n = 86), with a goal of identifying distinct clusters based on descriptive personality traits as measured by the Millon Clinical Multiaxial Inventory-II (MCMI-II). Three clusters were identified, accounting for 97% of study participants with available data. Additional analyses were conducted to explore differences and similarities among the three groups. The three clusters were comparable with respect to symptomatology (i.e., depression, anxiety, hopelessness), psychiatric diagnoses, and negative life stress, suggesting that cluster differences were not due to severity of disturbance (i.e., symptom severity) or diagnosis. Although all three clusters evidenced prominent negativistic and avoidant traits and two of the clusters showed prominent borderline traits, each was characterized by a distinct trait with implications for interpersonal functioning. Results are discussed in terms of implications for treatment and future research, particularly the importance of the therapeutic relationship with suicidal patients.

Adult↗
PubMedDate not supplied

Prenatal diazepam: chronic anxiety and deficits in brain receptors in mature rat progeny.

Pregnant rats were treated with daily doses (5.0 to 7.5 mg/kg, SC) of the benzodiazepine (BDZ) receptor agonist, diazepam (DZ) between day 15 through day 20 of gestation, i.e., during ontogenesis of BDZ receptors in an attempt to alter their development. In the radial arm maze, 6 months old rat progeny showed behavioral anomalies and deficient exploratory behavior. One plausible interpretation of their poor performance is a deficit in short-term spatial "working memory." However, a more detailed evaluation of their behavior suggests a chronic state of hyperarousal/anxiety and thus, poor focus of attention on the task at hand. In addition, the number of brain BDZ receptors in the thalamus, at the age of one year, was significantly reduced. Hence, prenatal exposure to DZ has enduring and detrimental effects on brain function.

Animals↗
PubMed1997

Prenatal stress induces high anxiety and postnatal handling induces low anxiety in adult offspring: correlation with stress-induced corticosterone secretion.

It is well known that the hypothalamo-pituitary-adrenal (HPA) axis is altered by early environmental experiences, particularly in the perinatal period. This may be one mechanism by which the environment changes the physiology of the animal such that individual differences in adult adaptative capabilities, such as behavioral reactivity and memory performance, are observable. To determine the origin of these behavioral individual differences, we have investigated whether the long-term influence of prenatal and postnatal experiences on emotional and cognitive behaviors in adult rats are correlated with changes in HPA activity. To this end, prenatal stress of rat dams during the last week of gestation and postnatal daily handling of rat pups during the first 3 weeks of life were used as two environmental manipulations. The behavioral reactivity of the adult offspring in response to novelty was evaluated using four different parameters: the number of visits to different arms in a Y-maze, the distance covered in an open field, the time spent in the corners of the open field, and the time spent in the open arms of an elevated plus-maze. Cognitive performance was assessed using a water maze and a two-trial memory test. Adult prenatally stressed rats showed high anxiety-like behavior, expressed as an escape behavior to novelty correlated with high secretion of corticosterone in response to stress, whereas adult handled rats exhibited low anxiety-like behavior, expressed as high exploratory behavior correlated with low secretion of corticosterone in response to stress. On the other hand, neither prenatal stress nor handling changed spatial learning or memory performance. Taken together, these results suggest that individual differences in adult emotional status may be governed by early environmental factors; however, perinatal experiences are not effective in influencing adult memory capacity.

Analysis of Variance↗
PubMed1993

Different behavioral profiles of the non-peptide substance P (NK1) antagonists CP-96,345 and RP 67580 in Swiss albino mice in the black-and-white box.

The non-peptide NK1 antagonists, RP 67580, and (2S,3S)-CP-96,345, the NK1 receptor-selective enantiomer of the racemic compound, were tested in Swiss albino mice in the black-and-white box behavioral paradigm. Both qualitatively and quantitatively, (2S,3S)-CP-96,345 produced the same behavioral effects as the racemic compound. In contrast, RP 67580 decreased exploratory behavior only in the white section, whereas crossings and rearings in the black section were not changed. In addition, RP 67580 decreased transitions. While the observed changes induced by CP-96,345 are caused by sedation and motor impairment, the effects of RP 67580 might be due to sedation plus an additional anxiogenic effect.

Animals↗
PubMed1996

'Quality of life' after therapy in rats with myocardial infarction: dissociation between hemodynamic and behavioral improvement.

Rats with myocardial infarction provide a clinically relevant model for hemodynamic and survival studies. Moreover, behavioral changes in this model, i.e. increased anxiety and reduced interest in environment and social interactions, mimic aspects of the reduced quality of life of patients. In the present study, we investigated whether pharmacological treatment that is known to improve hemodynamics and prognosis could also affect the behavioral changes associated with quality of life. Rats with 3-week-old infarcts were treated with intermittent dobutamine (1 mg/kg i.p., twice daily) or captopril (2 milligrams in drinking water). After 2 weeks of treatment, when from previous studies hemodynamics are expected to be restored, behavioral tests were performed. In the free exploration test, which primarily evaluates exploratory behavior, dobutamine normalized the reduced interest in the environment. In the standard open field and social interaction tests, which also include an anxiety component, the beneficial effects of dobutamine were not observed. In contrast, captopril normalized all behavioral changes that indicated increased anxiety. In conclusion, the expected similar hemodynamic improvement with dobutamine and captopril treatment resulted in improvement of different aspects of the changed behavior of rats with myocardial infarction, indicating that there is no direct relationship between hemodynamics and quality of life. The behavioral tests used, in combination with our previously described functional hemodynamic measurements, could provide a new basis for evaluating the effects of therapy on hemodynamic function as well as the quality of life.

Animals↗
PubMed2003

A heparin derived oligosaccharide normalizes the fear response of old Brown Norway rats.

Old animals exhibit impaired spatial learning and an exaggerated response to stress. It was predicted that the heparin derived oligosaccharide (HDO), C3, would reverse these age-related deficits. Young (4-5 months) and old (19-20 months) Brown Norway male rats ingested C3 (25 mg/kg per day, p.o.) or vehicle (drinking water) daily for 42-44 days. Two weeks after the initiation of drug treatment, the rats were examined using a series of behavioral tests. The old control rats evidenced: (1) increased neophobia and reduced exploratory behavior in a novel open field (OF); and (2) exaggerated freezing during the acquisition and retention of a conditioned response (CR) to a Pavlovian light-shock pairing ("foreground" conditioning). C3 treatment attenuated or reversed this age-related impairment of emotional behavior. Analysis of spatial learning using the Morris water maze (MWM), and of CR formation to the place in which the foreground conditioning was conducted ("background" conditioning) during context dependent fear conditioning (CDFC) did not reveal major age or drug effects on memory processes. It is hypothesized that C3 repairs damage to the extracellular matrix (ECM) that occurs during the aging process and thereby normalizes age-related exacerbated fear behaviors without affecting mnestic processes.

Aging↗
PubMed1985

Suppression of corticosterone synthesis alters the behavior of hippocampally lesioned rats.

The suppression of corticosterone synthesis with metyrapone (25 mg/kg) reduced the hyperactivity and altered the exploratory activity of hippocampally lesioned animals (HPC) in the open field to the level of cortical and sham controls (Experiment 1). In a second experiment, corticosterone (600 micrograms/kg) pretreatment 2 h, but not 1 h, before metyrapone partially restored the hyperactivity of HPC animals that had been decreased by the corticosteroid-suppressant drug. Alterations in exploratory behavior induced by metyrapone were also prevented by corticosterone pretreatment. The results suggest that the suppression of corticosterone in hippocampally lesioned animals produces a normalization of behavior that can be prevented by pretreatment with corticosterone.

Animals↗
PubMedDate not supplied

[Rapid tolerance to ethanol and high voluntary alcohol consumption in mice selected for brain weight].

Mice of two strains selected for small and large brain weight (SB and LB, respectively) had free access to 10% alcohol and water within three months. At the end of this period, they consumed alcohol in daily dose of 6.9 +/- 0.9 and 7.5 +/- 0.8 g/kg, respectively. After a period of imposed three-day abstinence, the alcohol consumption by the mice of these strains increased by 68.6 and 49.3%, respectively. Exploratory behavior of independent groups of mice from these strains was studied in the closed cross-maze. The animals were injected with ethanol (2.4 g/kg, i.p.) or vehicle twice with a weekly interval. In SB mice, the first ethanol administration increased the total time of maze exploration and the number of stereotyped visits. The second ethanol administration did not increase the time of exploration but increased the number of stereotyped visits even to the greater extent. The latter indicates the development of rapid tolerance and sensitization of these behaviors to the drug, respectively. The ethanol administration inhibited exploratory patrolling behavior and defecations. In LB mice, both the first and second ethanol administrations increased the number of stereotyped visits and decreased the exploration time and the number of defecations. The results do not support the psychomotor stimulant hypothesis of alcohol addiction. It is proposed that SB and LB mice may serve as models for Cloninger's types 1 and 2 alcoholics and may be useful for investigation of neuropharmacological mechanisms of stimulatory and inhibitory effects of ethanol.

Alcohol Drinking↗
PubMed1986

Effect of skimmianine on animal behavior.

Skimmianine, a component of Rutaceae plants, was found to have a significant inhibitory effect on spontaneous motor activity, exploratory behavior, cataleptogenic activity, conditioned avoidance response and long-term isolation-induced fighting of animals. A mild antimethamphetamine activity was also observed. Its neuroleptic activity was less potent than that of chlorpromazine.

Aggression↗
PubMed1994

[Postoperative behavior of gastrectomized rats in an open field after Roux-Y-reconstruction with and without pouch].

In a series of experimental studies on rat behavior following reconstructive surgery after gastrectomy the effects of Roux-Y-Pouch-technique (RY-P) as compared to Roux-Y (RY) alone were observed. 12 rats with RY-P and 13 rats with RY were tested on days 100-105 post surgery using the Open-Field-test paradigm. Feeding behavior and weight were additionally controlled. Data analysis of repeated measurement design (ANOVA) revealed significant group x time-interaction between type of reconstruction and exploratory behaviors (p < .01). Moreover, RY-P rats consumed more food (p < .001), had higher weight gain (p < .01), and tended to more normal defecation. Overall, results favour the more physiological type of reconstruction.

Anastomosis, Roux-en-Y↗
PubMed1989

Behavioral responses to novelty and structural variation of the hippocampus in mice. I. Quantitative-genetic analysis of behavior in the open-field.

As a first step towards a multivariate quantitative-genetic analysis of covariations between heritable variation in hippocampal structure and mouse behavior, a univariate analysis of the genetic architecture of behavioral responses to novelty is presented. For several components of exploratory behavior considerable amounts of genetic variation were found and an evolutionary history of stabilizing selection for intermediate levels of exploration was inferred. Comparison of these results with those from a previous study indicated that even a relatively small diallel cross, involving 4-5 inbred strains, may provide useful genetic information on a specific sample of animals. Larger numbers of strains are needed to provide precise estimates of genetic parameters in a population.

Animals↗
PubMed1975

Effects of the lesion of the postcommissural part of the septum on the behavior of the rat.

The effects of the lesion of the postcommissural part of the septum on behavior of the rat has been studied. Results may be summarized as follows. An increase in the exploratory behavior in the open field which decreases rapidly; a decrease in the number of defecations in this test and a decrease in time leaving a dark environment for exploration. In the shuttle box test, no facilitation of the acquisition, but a permanent and quite significant increase in the intertrial activity has been found. We conclude that the lesions tend to decrease the emotivity of the subjects. An interpretation on the basis of the species -- specific defensive reactions explains the transitory and permanent effects of the lesions on the spontaneous activity.

Aggression↗