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Results for “Exploratory Behavior”

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At least 613 records · Page 34Linked to original sources

PubMed1979

Effects of 6-hydroxydopamine and 6-hydroxydopa on development of behavior.

Rats treated at birth with 6-hydroxydopamine (6-OHDA) (60 microgram/g, IP) or 6-hydroxydopa (6-OHDOPA X2) (60 microgram/g, IP at birth and 48 hr later) exhibited increases in general activity throughout the initial 5 weeks after birth, with peak activity occurring around 20 days postnatally. Activity changes in the 6-OHDOPAx2 group appeared to be due to increased exploratory behavior (ambulation, climbing, rearing, sniffing), while the 6-OHDA changes appeared to be due to the increased self-directed behavior (eating, grooming, scratching). Despite these behavioral differences there was no obvious difference between treated groups in norepinephrine (NE) levels in the various brain regions, i.e., all treatments resulted in a reduction in neocortical and hippocampal NE and an elevation in cerebellar NE. These findings suggest that noradrenergic neurons may be altered to different degrees by each agent in more discrete brain regions than were tested, or that other neurotransmitter systems may be more selectively altered by either of the drug treatments. Because striatal dopamine was unaltered in any of the groups, however, there is reason to question a previously suggested link between minimal brain dysfunction (MBD) and dopamine depletion in the neonatal brain.

Aging↗

PubMed2005

Effect of lead exposure on dopaminergic transmission in the rat brain.

Lead is a neurotoxicant with known behavioral and neurochemical effects. In this study we attempted to relate the behavioral effects of lead to neurotransmission. Oral administration of 1000 ppm of lead acetate to young rats for 30 days caused a reduction in locomotor activity and stereotypic exploratory behavior during a 20 min testing period. This locomotor hypoactivity induced by lead was accompanied by a reduction in stereotypic behavior (sniffing, lickings, biting and grooming). These outcomes suggested that lead might interfere with catecholaminergic and particularly dopaminergic neurotransmission. Therefore, we examined the effect of the lead acetate on the uptake of dopamine in striatal synaptosomal preparations. The collected data showed a clear inhibition of the uptake of 3H-DA with an IC50 of 3.5 x 10(-5)M. This inhibition of the uptake of dopamine suggests that the behavioral effects of lead may be involved in dopaminergic neurotransmission.

Administration, Oral↗

PubMed2000

Effects of chronic kombucha ingestion on open-field behaviors, longevity, appetitive behaviors, and organs in c57-bl/6 mice: a pilot study.

Kombucha is a lightly fermented tea beverage popularly consumed as a self-prescribed folk-remedy for numerous ailments. Kombucha is claimed to enhance cognition, aid weight loss, and prolong life. This pilot study reports longevity, general health, and open-field exploratory behavioral outcomes from a 3-y longitudinal study of 64 C57-BL/6 mice (males and females), half of which chronically drank kombucha, and all of which experienced natural mortality. Compared by MANOVA to controls, mice that drank kombucha showed greater vertical exploration (P = 0.001) and a sex-interactive effect in novel object manipulation (P = 0.049). MANOVA of kombucha-drinking mice compared to controls detected differences in appetitive behaviors (food consumption, P < 0.001; beverage consumption, P = 0. 008), and gross body weight (P < 0.001). Appetitive behaviors changed with the addition of voluntary exercise on a running wheel, with differing patterns of change noted for males and females. Both male and female mice who drank kombucha lived longer than controls (P < 0.001), with the greatest variability among the male mice (sex interactive effect, P < 0.001). Comparable effects and mechanisms in humans remain uncertain, as do health safety issues, because serious health problems and fatalities have been reported and attributed to drinking kombucha.

Animals↗

PubMed1998

Behavioral effects of neuropeptide E-I (NEI) in the female rat: interactions with alpha-MSH, MCH and dopamine.

The behavioral and neurochemical effects of NEI, and its interaction with alpha-MSH or MCH were investigated in the ventromedial nucleus (VMN) and medial preoptic area (MPOA) in female rats (bilateral administration, 100 ng in 0.5 microliter/side). NEI in the VMN (but not in the MPOA) stimulated exploratory behavior, increased anxiety and reduced dopamine and DOPAC release. The behavioral effects were antagonized by alpha-MSH. NEI stimulated female sexual receptivity in the MPOA. In the VMN, NEI did not have any effect on sexual activity, but partially antagonized the stimulatory effect of MCH. These results show that NEI in the hypothalamus participates in the regulation of behavior, possibly through dopaminergic mediation.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1982

Environmental effects on the ontogeny of exploratory and escape behaviors of Mongolian gerbils.

Mongolian gerbils reared in standard laboratory cages and gerbils reared in cages containing a burrowlike shelter did not differ in their rate of development of escape responses to sudden visual stimulation. The presence of shelter in the rearing environment did, however, markedly slow the development of adult-like patterns of exploration. Reduced exposure to illumination, experienced by shelter-reared subjects, proved responsible for this retardation of development. The effect of shelter-rearing on the development of exploratory behavior is interpreted as demonstrating an environmentally induced maintenance of an adaptive juvenile pattern of behavior.

Aging↗

PubMed2005

Lesions of the Edinger-Westphal nucleus alter food and water consumption.

The Edinger-Westphal nucleus (EW) produces several neuropeptides, including urocortin 1 and cocaine-amphetamine-regulated transcript, which regulate feeding, energy balance, and anxiety. Additionally, the EW projects to feeding and anxiety-regulatory brain areas. The authors tested the effect of lesions of the EW on the consumption of food, water and flavored solutions, metabolic indices, and exploratory behavior on the elevated plus maze in male C57BL/6J mice. EW lesion significantly reduced basal and deprivation-induced food and fluid consumption compared with sham and placement controls, but it did not alter behavior on the elevated plus maze. EW lesion had no effect on indices of basal metabolic activity, including plasma glucose level and body temperature. These effects suggest that the peptidergic neurons of the EW regulate food consumption.

Animals↗

PubMed2000

[Strain-specific response in mice to the neonatal administration of ACTH(4-10) fragment: behavior, neurochemistry, and brain morphology].

Neonatal injection of the ACTH4-10 fragment (5 micrograms daily for five days) caused genotype-dependent changes in concentrations of some monoaminergic neuromediators and their metabolites in hippocampus and brain stem of adult CBA and 101/HY mice. The catecholaminergic neurons increased in number in hypothalamic zona incerta of adult 101/HY mice. Neonatal injection of the peptide caused also genotype-dependent changes in the exploratory behavior of adult animals. Sound sensitivity was reduced in the 101/HY mice, whereas no sensitivity was revealed in both control and experimental groups of the CBA mice. The effects discovered were suggested to be caused by changes in neuronal differentiation.

Acoustic Stimulation↗

PubMed2004

Neurochemical and behavioral effects of the intrahippocampal co-injection of beta-amyloid protein1-40 and ibotenic acid in rats.

The present study was designed to investigate the effects of the intrahippocampal co-injection of beta-amyloid protein1-40 (Abeta(1-40)) with ibotenic acid (Ibo) on learning and memory in normal and aging model rats, and to explore the mechanism underlying the effects of the co-injection. The normal and aging rats were bilaterally injected Abeta(1-40) (4 microg for each side) with Ibo (2 microg for each side) into the hippocampus. Two weeks after the intrahippocampal injection, the exploratory behavior and learning-memory ability of the rats were tested by using open field, Y-maze and passive avoidance task. And the changes of membrane fluidity in hippocampal mitochondria, the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) in hippocampus were also examined. The co-injection of Abeta(1-40) with Ibo induced tested rats a remarkable decrease in the explorative behaviors and a significant decline in learning-memory ability (P < 0.01). The neurochemical changes induced by the co-injection included a significant decrease in membrane fluidity of hippocampal mitochondria (P < 0.01), a significant decrease in the activity of SOD (P < 0.01), as well as a remarkable increase in the content of MDA (P < 0.01). The results suggest that co-injection of Abeta(1-40) with Ibo may induce an increase of hippocampal damage by peroxidation and a serious deficit in the learning and memory of the rats. The results also suggest that the co-injection of Abeta(1-40) with Ibo may provide a useful animal model for the Alzheimer's disease (AD) research.

Aging↗

PubMed1984

Evaluation of a proposed hamster separation model of depression.

Phodopus sungorus, the Siberian dwarf hamster, exhibits a number of reproducible and quantifiable behavioral changes when the members of a male-female pair bond are separated. Preliminary evaluation of the syndrome revealed a significant increase in body weight, decrease in social interaction, and decrease in exploratory behaviors, which occurred predominantly in separated males. Some, but not all, of the behavioral effects of separation are reversed by the tricyclic antidepressant, imipramine. Separation of pair-bonded Siberian dwarf hamsters may provide a new animal model for depression, incorporating the practical advantages of a rodent model with the conceptual advantages of a naturalistic life event precipitant.

Animals↗

PubMed1994

Behavioral and anatomical deficits in mice homozygous for a modified beta-amyloid precursor protein gene.

The beta-amyloid precursor protein (beta APP) gene of the mouse was disrupted by inserting into exon 2 a cassette containing a neomycin resistance gene and a putative transcription termination sequence. Contrary to expectation, brain and other tissues from mice homozygous for the insertion still contained beta APP-specific RNA, albeit at a level 5- to 10-fold lower than wild type and lacking the disrupted exon, which had been spliced out. The brain contained shortened beta APP-specific protein at a low level. Mutant mice were severely impaired in spatial learning and exploratory behavior and showed increased incidence of agenesis of the corpus callosum.

Amyloid beta-Protein Precursor↗

PubMed1982

Phencyclidine retards autoshaping at a dose which does not suppress the required response.

Four groups of five food-deprived hooded Long-Evans rats were injected subcutaneously with saline (vehicle) or 2, 4 or 8 mg phencyclidine (PCP) hydrochloride/kg fifteen minutes before being placed for the first time into operant chambers modified to detect exploratory behaviors. Rearing was found to be more sensitive to disruption by phencyclidine than was unconditioned level touching (a measure of floor-level exploratory activities). In an autoshaping session immediately following, the group of animals given the low dose of PCP made as many lever-touch responses as the group given saline, but consumed fewer of the food pellets delivered. In addition, none of the animals in the low-dose group showed within-session shortening of the latency to respond which was observed in four of five control animals. The two other groups given higher doses of PCP demonstrated dose-related decrements in responding as well as a reduction in food pellet consumption during the first session of autoshaping. Over the next two daily autoshaping sessions, performance improved in those groups initially suppressed. Performance converged in all group by the third autoshaping session.

Animals↗

PubMed1994

Sex-dimorphic psychomotor activation after perinatal exposure to (-)-delta 9-tetrahydrocannabinol. An ontogenic study in Wistar rats.

The ontogeny and the adult expression of motor behaviors were studied in male and female rats born from mothers exposed to delta 9-tetrahydrocannabinol (THC, 5 mg/kg) during gestation and lactation. Perinatal exposure to THC increased both rearing and locomotor activities in males and females at immature preweanling ages (P-15 and P-20). These effects disappeared after ceasing THC exposure (postweaning ages), but they were observed again in adult (P-70) females. The effects appeared as persistently high motor activity in familiar environments, disappearing the characteristic habituation profile in locomotor and exploratory behaviors. In novel environment condition tests, adult (P-70) THC-exposed females, but not males, exhibited lower locomotor activity in the socio-sexual approach test, and an increase in the emergence latency in the dark-light emergence test. Additionally, animals of both sexes exposed to THC showed a increase in the time spent grooming measured in novelty conditions. These findings suggest that perinatal exposure to THC affects both the development and the adult expression of motor behaviors and it resulted in a sex-dimorphic psychomotor activation very similar to that observed after perinatal exposure to other drugs of abuse. A possible role of THC-induced pituitary-adrenal (PA) axis activation was also evaluated by measuring plasma corticosterone levels in adult animals perinatally exposed: THC-exposed females exhibit a clear increase of this adrenal hormone, whereas THC-exposed males displayed lower levels of this hormone.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1992

Behavioral and neurochemical indices of barrel cortex-basal ganglia interaction.

Previous experiments from our laboratory have shown a wide variety of time-dependent lateralized changes in behavior and nigrostriatal function following unilateral manipulation of the mystacial vibrissae of rats. The present experiment investigated the effects of unilateral radiofrequency lesion of the cortical vibrissae representation (the barrel fields) in light of these results. We measured lateralized changes in behavior as well as tissue monoamines in neostriatum and substantia nigra, between 1 and 16 days post-lesion. Short-term asymmetries in exploratory behavior (thigmotactic scanning) and neostriatal serotonin metabolism that lasted up to day 6 were seen. In substantia nigra, time-related asymmetries in dopamine concentrations were found with higher ipsilateral values on day 3 and higher contralateral values on day 6. After day 6, the animals had recovered from these acute effects and thereafter, neostriatal dopamine metabolism became asymmetrical. Also during this time, they showed a directional bias in spontaneous and apomorphine-induced turning. Finally, neostriatal serotonin was bilaterally elevated on day 16. These results parallel some of the effects previously seen following unilateral removal of the vibrissae, indicating that the barrel cortex is a critical link in the functional interaction between the vibrissae and basal ganglia.

Animals↗

PubMed1988

Effects of lateral and medial septal lesions on various activity and reactivity measures in rats.

Roles of the lateral and medial septum in the regulation of activity, reactivity and open field behavior in rats were examined in the present study. Effects of lateral, medial and combined lateral and medial septal lesions were studied, respectively. Our results indicate that lateral septal lesions significantly decreased locomotor activity and tended to decrease rearing response. While it also markedly increased movement time in the activity monitor, stereotyped behavior and tactile startle amplitude. The most significant findings with medial septal lesions were decreased activity, especially in the center area of an open field and decreased exploratory behavior in rats. For most behavioral measures, effects of combined lateral and medial septal lesions were similar to that of medial septal lesions alone except that it augmented startle response with a different response pattern compared to that of lateral septal lesions alone. The locomotion patterns of these animals also revealed some qualitative difference in their behavior. These results are further discussed in the scope of anatomical, neurochemical and pharmacological differentiations of the septum complex.

Animals↗

PubMed2004

Time window of fibroblast growth factor-18-mediated neuroprotection after occlusion of the middle cerebral artery in rats.

To assess the time window for fibroblast growth factor-18 (FGF18)-mediated neuroprotection, FGF18 was administered by intravenous infusion at various times after transient occlusion of the middle cerebral artery (MCAO) in rats. Vehicle or FGF18 (100 microg x kg(-1) x h(-1)) was infused at 0.25, 0.5, 1.0, 2.0, 4.0, or 8.0 hours after MCAO with infarct volumes and behavioral deficits measured at 24.0 hours after MCAO. A separate group of animals received the infusions 24 hours after MCAO with endpoints measured at 48 hours after MCAO. Infusion of FGF18 reduced infarct volumes and improved scores in tests of reference and working memory, motor ability, and exploratory behavior. FGF18 was most efficacious when infused within 2 hours after MCAO. Significant reductions in infarct volumes and reductions in deficits of reference memory and motor activity were also observed with FGF18 infused 24 hours after MCAO. Measurements taken at infusion times before 2 hours after MCAO showed that regional cerebral blood flow was increased by FGF18. Administration of vehicle or FGF18 had no significant effect on mean arterial blood pressure, heart rate, brain temperature, blood pH, Pco2, or Po2. These results demonstrate that FGF18 is an effective neuroprotective agent when administered early after transient MCAO in rats. Efficacy observed with infusions at later times suggests an expanded time window for FGF18-mediated neuroprotection.

Animals↗

PubMed1996

Schistosoma mansoni: influence of infection on mouse behavior.

Schistosoma mansoni infection in humans and animals induces abnormal neurobehavioral responses following granuloma formation. In mice, granulomas in the liver are observed 8 weeks after infection, while after 15-20 weeks, the presence of eggs and granulomas in the brain has been reported. In this study, outbred CD-1 female mice were infected with S. mansoni and examined in several behavioral tests (open field, novel object investigation, black/white box, and hot plate) 8 and 15 weeks after infection. The detected effects of schistosome infection were a reduction of body weight in 8-week infected mice, marked changes in exploration/activity, rearing, and wall-rearing in 8- and 15-week infected mice, an enhancement of sniffing and grooming in 8-week infected mice, and finally an increase in the threshold of pain response to the hot plate in 15-week infected mice. The results of the present study indicate that S. mansoni infection markedly alters exploratory behavior of mice, affecting particularly the vertical movements of the animals, and suggests that the differences in behavioral abnormalities between 8- and 15-week infected mice might be associated with modifications in the levels of nerve growth factor and cytokines induced by granulomas.

Analysis of Variance↗

PubMed2004

Maternal separation alters maternal care, but has minor effects on behavior and brain opioid peptides in adult offspring.

The aim of the study was to investigate the effect of repeated maternal separation (MS; 4 hr per day) during postnatal Days 1 to 15 on emotionality and voluntary ethanol intake in adult male and female Wistar rat offspring relative to controls exposed to a brief (5-min) daily handling procedure. Brain immunoreactive opioid peptide levels and plasma levels of corticosterone also were measured. There were mainly no alterations in any of the tested behaviors (i.e., fleeing and freezing responses, exploratory behavior, spontaneous and amphetamine-induced locomotor activity and competitive behavior), ethanol intake, or immunoreactive opioid peptide levels in MS offspring, either in males or females, compared to their respective controls nor were there any differences in plasma corticosterone between groups. In addition, the dams' retrieval behavior of the pups also was studied, showing that MS dams spent more time in the nest with the pups after the 4-hr separation period compared to control dams. With respect to the used protocol of the MS procedure in the present study, our results do not provide support for the suggestion that this procedure is a relevant model for studying development of psychopathology and vulnerability to drug abuse.

Animals↗

PubMed1999

Chronic administration of propranolol impairs inhibitory avoidance retention in mice.

Adrenergic systems are importantly involved in memory storage processes. As such, agents that alter adrenergic receptors, such as "beta-blockers," also alter memory storage. However, the anxiety literature cautions that beta-adrenergic receptor antagonists, such as propranolol, may have different behavioral effects with acute vs chronic dosing. The effects of chronic propranolol specifically on memory modulation are unknown. This study was designed to evaluate the effects of chronic propranolol on retention for an aversive task, in which there is endogenous adrenergic activation. Adult male ICR mice were given daily injections of one of four doses of propranolol (2, 4, 8, and 12 mg/kg) or 0.9% NaCl vehicle for 15 days prior to, and continuing during, behavioral tests of exploration and retention. Exploratory behavior, as an index of anxiety level, was measured in a conventional elevated plus-maze, whereas retention of an aversive experience was measured in a step-through inhibitory avoidance apparatus. Sensitivity to aversive footshock was also evaluated. Compared to controls, propranolol-treated mice showed a dose-dependent decrease in retention for the inhibitory avoidance task, but no effect on anxiety on the plus-maze or on footshock sensitivity. Taken together with results from previous studies, it is apparent that propranolol can have different behavioral effects when administered acutely vs chronically, and its chronic effects significantly impair memory storage processes. Since these drugs are typically used chronically, and often in older adults, they could contribute to functional memory impairments.

Adrenergic beta-Antagonists↗