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PubMed2005

Serotonin type 3 receptors stimulate offensive aggression in Syrian hamsters.

Hamsters repeatedly exposed to cocaine during adolescence display high levels of offensive aggression compared to saline-treated littermates. The escalated offensive phenotype observed in adolescent cocaine-treated animals is modulated by serotonin (5-HT) signaling and can be suppressed by inhibiting 5-HT type 3 receptors, suggesting that these receptors might play an important role in the aggression-stimulating effects of adolescent cocaine exposure. The current study examined this hypothesis and extended earlier studies investigating the relationship between 5HT(3) receptor neural signaling and the offensive response patterns of aggressive, adolescent cocaine-treated animals compared to non-aggressive, saline-treated littermates. Adolescent cocaine-treated hamsters and saline-treated littermates were tested for offensive aggression after the administration of either the 5-HT(3) antagonist 3-tropanylindole-3-carboxylate methiodide (tropisetron) or the 5-HT(3) agonist 1-(m-chlorophenyl)-biguanide hydrochloride (mCPBG). Tropisetron significantly reduced the high levels of offensive responding observed in adolescent cocaine-treated animals, whereas treatment with the 5-HT(3) receptor agonist mCPBG failed to affect the escalated offensive response. Conversely, tropisetron failed to affect very low, baseline levels of aggressive responding seen in adolescent saline-treated animals, while 5-HT(3) receptor activation via mCPBG triggered highly escalated levels of offensive aggression in these animals. Together, these data support a stimulatory role for 5-HT(3) neural signaling in offensive aggression.

Age Factors↗
PubMed1981

Stereoselective effects of opiate agonists and antagonists on ingestive behavior in rats.

In male Sprague Dawley rats, the (-)-isomer of the opiate antagonist GPA 1843 (beta-9-methyl-5-phenyl-2-allyl-2'-hydroxy-6, 7-benzomorphan) produced dose-related decreases in nocturnal feeding and of hyperphagias induced by 2-deoxy-D-glucose (2-DG; 400 mg/kg) and 24 hr food deprivation (FD). The hyperphagia induced by insulin (10 U/kg) was not significantly decreased by GPA 1843. In contrast, comparable doses of the (+)-stereoisomer, GPA 1847, had no effect on nocturnal, 2-DG or FD hyperphagia. In addition, hyperphagia and hyperdipsia were observed following administration of the opiate agonist levorphanol, but not its stereoisomer, dextrorphan. Thus, the effects of these agents on consummatory behavior are mediated by a stereospecific interaction with opiate receptors, which further indicates that endogenous opiate peptides are involved in the expression of these opiate-related hyperphagias.

Animals↗
PubMed1986

Food hoarding and ingestion in the deer mouse, Peromyscus maniculatus: selective responses to mu and kappa opiate agonists.

The feeding behavior of the deer mouse, Peromyscus maniculatus, includes food hoarding as well as ingestion. Administration of the prototypical mu opiate agonist, morphine sulfate, 1-20 mg/kg, produced over three hours a significant dose-dependent stimulation of hoarding by free feeding deer mice. The specific kappa opiate agonist, U-50,488H, 0.10-10 mg/kg, markedly increased ingestion without having any augmentatory effects on hoarding. The mixed mu and kappa opiate agonist, ketocyclazocine hydrochloride, 1-10 mg/kg, as well as various combinations of morphine sulfate and U-50,488H, augmented both hoarding and ingestion. Food restriction for 24 hr caused a significant, naloxone (1.0 mg/kg) reversible, increase in food intake. Food deprivation also modified the hoarding and ingestion responses of the deer mice to the mu and kappa opiate agonists, reducing the relative amounts of food that were hoarded. These results indicate that mu and kappa opioid systems are differentially involved in the mediation of various aspects of feeding. This also suggests that environmental factors, such as food restriction, can modify the relative roles of mu and kappa opioid systems in the expression of feeding behavior.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1977

Single unit recording in the midbrain of rats during shock-elicited fighting behavior.

Single unit activity was recorded extracellularly from the midbrain of rats during fighting behavior and during non-fighting control manipulations. Fighting behavior was elicited by footshock or startle stimuli or occurred spontaneously as a result of prior footshock presentations. Seven cells were found in the midbrain reticular formation and central gray which displayed maximum firing rates during fighting behavior. These cells also fired to a limited extent to some of the control manipulations, particularly contralateral vibrissae stimulation. These cells fired phasically during fighting behavior and their firing was correlated with either the approach or paw-strike of the opponent animal or to the response of the recording animal to a tactic of the opponent animal. However, no specific movement or sensory event reliably predicted the firing of these cells during fight sequences. Cells located in other midbrain areas, such as the deep tectum or the area of the red nucleus, also responded during fighting behavior. However, the discharge of these cells was correlated with specific body movements or sensory events. The activity during fighting was similar in rate and pattern to activity during control manipulations whenever similar movements or sensory stimulation were produced. Cells were also found which did not discharge during fighting behavior although they fired under a variety of other conditions.

Action Potentials↗
PubMed1982

beta-Glucuronidase activation of latent aggression-promoting cues in mouse bladder urine.

The present study was designed to investigate the chemical properties of the aggression-promoting cues present in bladder urine of male mice. The results of the first experiment confirmed earlier work by demonstrating the presence of an aggression-promoting chemosignal in bladder urine. In Experiment 2, behavioral assays were separately performed on the organic and aqueous layers of bladder urine obtained by repeated dichloromethane extractions. Only the combined organic layers of the initial three extractions demonstrated behavioral activity. A fourth extraction showed no behavioral activity for both organic and aqueous layers. However, the findings of Experiment 3 showed that incubation of the aqueous layer from the third CH2Cl2 extraction in beta-glucuronidase can free additional aggression-promoting cues into a subsequent CH2Cl2 extraction. It is concluded that two forms of the aggression-promoting chemosignal are present in bladder urine. One is lipophilic and behaviorally active, whereas the other is conjugated, possessing latent chemosignal properties.

Aggression↗
PubMed1993

Intermale aggression in mice: does hour of castration after birth influence adult behavior?

In the mouse, perinatally present testicular androgens promote the development of the propensity for adult intermale aggression. In the newborn male mouse plasma testosterone more than doubles during the first 2 h after birth and then falls rapidly to remain relatively low for the remainder of the 24-h period after birth. To study whether this surge in plasma testosterone influences aggressiveness we castrated some male mice within 1 h after birth i.e., before the surge. We castrated other males between 1.5-6 h after birth, or 1, 6, or 12 days after birth. Males were given testosterone as adults and tested for aggression for 5 weeks. Males castrated within 1 h after birth were not clearly different from males castrated 1.5-6 h after birth with respect to aggressive behavior, although males in both groups were substantially less aggressive than males castrated later in life. Thus, the perinatal surge in plasma testosterone in the mouse does not appear to make a unique contribution to the organization of mechanisms for intermale aggression. Rather, this surge is probably the initial stimulus that begins the postnatal process by which testicular hormones promote the development of the potential for adult aggressive behavior. This process appears to be complete by 6 days after birth.

Aggression↗
PubMed1994

Control of territorial aggression in a changing environment.

A sedentary population of song sparrows, Melospiza melodia morphna, in western Washington State shows year-round territoriality but in different contexts. During the breeding season (March-August), all defend multiple purpose territories as monogamous pairs, or alone, but only about 30% of individuals remain on the same territory during the nonbreeding season (September-February). During the breeding season, territorial behavior is tightly correlated with circulating levels of luteinizing hormone (LH) and testosterone, but identical behaviors during the nonbreeding season appear to be expressed independently of gonadal hormones. First summer males establish territories with basal plasma levels of LH and testosterone. Castrated male song sparrows defend territories equally well as intact males in autumn and continue to do so even through onset of the breeding season. It can therefore be questioned whether testosterone has any role in activation of territorial behavior in this species. Experiments in which testosterone levels were manipulated indicate that testosterone does not simply activate territorial behavior but enhances "persistence" of aggression during the breeding season. It is suggested that although territorial behavior may be expressed year-round, the context, neural, and hormonal bases of territoriality may change dramatically.

Aggression↗
PubMed2000

Abusive behavior is barrier to high-reliability health care systems, culture of patient safety.

Addressing abusive behavior in the medical workplace presents an important opportunity to deliver on the national commitment to improve patient safety. Fundamentally, the issue of patient safety and the issue of abusive behavior in the workplace are both about harm. Undiagnosed and untreated, abusive behavior is a barrier to creating high reliability service delivery systems that ensure patient safety. Health care managers and clinicians need to improve their awareness, knowledge, and understanding of the issue of workplace abuse. The available research suggests there is a high prevalence of workplace abuse in medicine. Both administrators at the blunt end and clinicians at the sharp end should consider learning new approaches to defining and treating the problem of workplace abuse. Eliminating abusive behavior has positive implications for preventing and controlling medical injury and improving organizational performance.

Agonistic Behavior↗
PubMed2005

GABA receptor agonists in the medial preoptic area and maternal behavior in lactating rats.

We studied the effects of injecting agonists of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) muscimol (GABA-A receptor agonist) and baclofen (GABA-B receptor agonist) in the medial preoptic area (MPOA) and neighboring brain regions, the bed nucleus of the stria terminalis (BNST), and lateral preoptic area (LPO) on maternal behavior. Lactating female rats were implanted with bilateral cannulae in the MPOA/BNST on day 1 postpartum. On day 5, a maternal behavior test was conducted in the home cage after females received injections of muscimol or baclofen (0, 12.5, 50 or 200 ng per side). On day 7, after MPOA/BNST injections, a second maternal behavior test was conducted with pups placed at the end of a T-runway projecting from the home cage. Finally, after injections on day 9 maternal aggression, olfaction, and locomotor behavior were tested. The GABA receptor agonists injected in the MPOA/BNST produced dose-dependent deficits in all components of maternal behavior, including maternal aggression, except licking. Muscimol produced deficits in the active component, nest building at lower doses than baclofen, both agonists produced deficits in retrieving, while baclofen produced deficits in passive components (hovering and crouching over pups) at lower doses than muscimol. Both GABA receptor agonists increased locomotor activity and reduced olfactory responsiveness but these were only correlated with deficits in retrieving and crouching in baclofen-treated females.

Analysis of Variance↗
PubMed2002

A specific anti-aggressive effect of repeatedly administered lobeline.

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 attack behaviour without significantly increasing immobility or changing any other behavioural category involving motor activity. In contrast, nicotine did not significantly alter time allocated to any behavioural category.

Aggression↗
PubMed1994

Behavioral and hormonal responses of male song sparrows to estradiol-treated females during the non-breeding season.

Previous studies on several species have shown that behavior of female vertebrates given estradiol implants to maintain sexual receptivity resulted in elevated levels of testosterone in males and even delayed termination of breeding in their otherwise untreated mates. However, the efficacy of such treatment in the non-breeding season was unclear. In this study, female song sparrows, Melospiza melodia morphna, given implants of estradiol in autumn showed elevated sexual behavior--especially "chitters," a loud, female-specific vocalization used mostly during the breeding season. Males in autumn appeared to ignore the sexual behavior of these females, showed no difference in response to simulated territorial intrusion, and had basal circulating levels of testosterone when compared with males tested in an area of control females. However, by late winter (February) males in the area where females were treated with estradiol had elevated levels of testosterone compared to control males and those of both groups sampled in autumn. These data indicate that sexual behavior of females, experimentally induced by estradiol implants, failed to increase sexual and territorial behavior in males during the autumn. On the other hand, reproductive behavior of females did appear to accelerate the vernal increase in testosterone concentrations in blood of males.

Aggression↗
PubMed2001

Vasopressin and aggression in cross-fostered California mice (Peromyscus californicus) and white-footed mice (Peromyscus leucopus).

To examine how developmental experiences alter neural pathways associated with adult social behavior, we cross-fostered pups between the more aggressive and monogamous California mouse (Peromyscus californicus) and the less aggressive and polygamous white-footed mouse (P. leucopus). Cross-fostered males became more like their foster parents when tested as adults. Male white-footed mice became more aggressive only in an aggression test in a neutral arena, whereas the territorial California mice became less aggressive in resident-intruder aggression test, as measured by attack latency. Only the species that displayed a change in resident-intruder aggression showed a change in arginine vasopressin (AVP) levels: cross-fostered California mice had significantly lower levels of AVP-immunoreactive (AVP-ir) staining than controls in the bed nucleus of the stria terminalis (BNST) and the supraoptic nucleus (SON) and a nonsignificant trend toward lower levels in the medial amygdala (MA). Neither species showed changes in AVP-ir staining in a control area, the paraventricular nucleus (PVN). The changes in AVP-ir staining in the BNST and SON may not be caused by stress because cross-fostering was not associated with changes in adult plasma concentrations of two steroid hormones, corticosterone and testosterone, that have been associated with stress-related alterations in AVP pathways. These results suggest that manipulating the early parental environment can directly alter both a neurotransmitter system and species-typical patterns of social behavior, but that these effects may vary between species and under different social contexts.

Aggression↗
PubMedDate not supplied

Effects of prenatal AZT on mouse neurobehavioral development and passive avoidance learning.

Recent evidence has shown that perinatal administration of zidovudine (AZT) to HIV-infected mothers reduces the risk of maternal-infant transmission of the virus. Treatment of pregnant seropositive women with AZT is becoming a common medical practice, despite the paucity of information about the potential neurotoxic/behavioral-teratogenic effects of AZT on the developing organism. The aim of the present study is to evaluate in mice the short-, medium-, and long-term effects of prenatal exposure to AZT on neurobehavioral development. Pregnant mice were given 0.2, 0.4, and 2.0 mg/ml AZT in drinking water from day 10 of gestation to delivery. Offspring's viability was severely affected in the 2.0 mg/ml AZT group. Thus, behavioral analysis was carried out in offspring of 0.2 and 0.4 mg/ml AZT-treated females only. Some limited but significant alterations were found, such as stunted body weight, delayed appearance of the pole-grasping reflex, and a slight impairment in the acquisition phase of a passive avoidance response. Moreover, sexual differences in some items of the social behavior repertoire appeared to be affected by AZT treatment.

Agonistic Behavior↗
PubMed1990

Neonatal 6-hydroxydopamine alters the behavior of enriched-impoverished rats in a novel test environment.

The hypothesis that neonatal norepinephrine (NE) depletion lessens the behavioral consequences of differential housing was tested. Male Wistar rats were injected with 6-hydroxydopamine (6-OHDA) or vehicle twice within 24 hr of birth, weaned at 25 days, and reared under either impoverished (IC) or enriched conditions (EC) for 30 days. In 3 experiments, rats were tested in the Morris water maze, the colony-intruder test, and 2 tests of dominance. 6-OHDA treatment reduced cortical and hypothalamic NE concentrations and increased brainstem NE concentrations. EC housing increased cortical dopamine (DA). Behavioral differences caused by postweaning enrichment-isolation were reduced by neonatal NE depletion, primarily in early test trials. The authors conclude that forebrain NE afferents from the locus coeruleus are important for housing-related behavioral changes and responsivity to novel testing environments.

Agonistic Behavior↗
PubMed1994

Overexpression of transforming growth factor alpha in transgenic mice alters nonreproductive, sex-related behavioral differences: interaction with gonadal hormones.

Sexually dimorphic differences in voluntary sodium intake, locomotor activity, immobility in the swim test, and aggressive behavior were found to be altered in transgenic CD-1 mice that overexpressed transforming growth factor alpha (TGF alpha). In contrast to nontransgenic CD-1 mice, immobility in the swim test was longer and sodium intake higher in the male TGF alpha mice than in the female TGF alpha mice. These findings indicate that the male TGF alpha mice exhibited feminization of some behaviors. Furthermore, the male TGF alpha mice were highly aggressive. Castration reversed the behavioral effects in the adult male transgenic mice, but ovariectomy did not reverse the behavioral effects in the adult female transgenic mice. Thus the feminizing effect of TGF alpha on some nonreproductive behaviors and increased aggressive behavior in male mice may be mediated through an interaction between this growth factor and gonadal hormones.

Affect↗
PubMed2001

Short-term stability and prospective correlates of bullying in middle-school students: an examination of potential demographic, psychosocial, and environmental influences.

Stability and change of bullying over a four-month interval was examined in 516 middle school students (grades 6-8). The stability coefficient was .65 for the entire sample. There was a significant increase in bullying behavior from Time 1 to Time 2 for 6th grade students; no significant change in bullying was found among 7th or 8th graders. For 6th graders, a greater confidence in using non-violent strategies was associated with less bullying at Time 2, while beliefs supportive of violence and misconduct, less positive adult influences, and more negative peer influences were associated with greater likelihood of bullying at Time 2. Higher levels of impulsivity, anger, and depression were also associated with greater levels of bullying over time. Several explanations for the increase in bullying behaviors among 6th graders are discussed and linked to intervention efforts.

Adolescent↗
PubMed1992

Behavioral, endocrine, and immunological correlates of immigration by an aggressive male into a natural primate group.

A very aggressive young adult male entered one of three long-term study groups of yellow baboons. Papio cynocephalus, approximately 3 weeks after an immobilization project began. The immigrant male's rate of agonistic encounters was appreciably higher than average, and these interactions disproportionately involved adult females as targets. Basal cortisol concentrations were higher and total lymphocyte counts lower for individuals immobilized during the immigration situation than for other individuals; these effects were greater for females than for males. Among animals whose endocrine data were obtained during the immigration period, some were specific targets of the immigrant male's aggression and others were not. Lymphocyte counts were significantly lower for those individuals who were victims of the male's aggression than for noninvolved individuals; a nonsignificant tendency toward higher basal cortisol concentrations for victims was observed as well. The immigrant male himself had a high basal cortisol concentration, a low lymphocyte count, and a testosterone concentration that was triple the average for adult males and almost double the second highest value in the population.

Aggression↗