Effect of chronic social stress on delta-opioid receptor function in the rat.
Previous studies have shown that stressors modify endogenous opioid systems. However, the consequences of social stress on the function of endogenous opioid systems is not well documented. The present studies investigated the effect of rank and housing condition on response to SNC-80, a delta receptor agonist. Triad-housed rats were assessed for dominance status by their behavior and alteration in body weights. At 3 and 50 days, triad- and individually housed rats were injected with SNC-80 (35 mg/kg i.p.) or saline, and evaluated using a test battery consisting of open field behaviors, rectal temperature, analgesia, and air-puff-induced ultrasonic vocalizations. After 50 days of housing, plasma corticosterone, adrenal catecholamines, and the density of cyclic[D-penicillamine2-D-penicillamine2]enkephalin-stimu lat ed guanylyl 5'-[gamma[35S]thio]-triphosphate binding in the prefrontal cortex, the amygdala, nucleus accumbens, thalamus, arcuate, and median eminence were also determined. The first 24 h of triad housing resulted in loss of body weight in subdominant (betas and gammas) but not dominant alpha rats. SCN-80-induced hypothermia was smaller, and there was no depression of headpoke and locomotor behavior in the periphery and the center of the field of alpha rats, in contrast to subdominant and singly housed rats. Rank status did not influence SNC-80's analgesic effect or its inhibition of air-puff-induced ultrasonic vocalizations. Plasma corticosterone levels of alphas and gammas were lower compared with betas and singly housed rats. Agonist stimulation of delta receptor guanylyl 5'-[gamma[35S]thio]-triphosphate binding was lateralized in prefrontal cortex and amygdala, but not nucleus accumbens. Binding was highest in all brain areas of singly housed rats and lowest in the thalamus of beta and of gamma rats. Lateralized binding in amygdala, high locomotor activity, and sensory sensitivity correlated positively with greater sensitivity to SNC-80-induced depression in these measures. Higher binding in the right amygdala correlated with higher plasma corticosterone levels. These findings indicate that dominant rats displayed stimulant rather than depressant responses to delta-opioid activation. Therefore in rodents rank-related stress can alter responsiveness of the endogenous opioid system, and dominance can increase the excitatory effects of delta agonists. (+info)
Agonistic behaviour and biogenic amines in shore crabs Carcinus maenas.
To investigate the role of certain neurohormones in agonistic behaviour, fights were staged between pairs of size-matched male shore crabs Carcinus maenas, and blood samples were taken immediately after the contests had been resolved. Samples were also taken from these crabs at rest (before and after fighting) and after walking on a treadmill. A control group of crabs also had samples taken on each experimental day. Concentrations of tyramine, dopamine, octopamine, serotonin (5-HT) and norepinephrine were determined in each blood sample using a gas chromatography/mass spectrometry (GC-MS) system. Norepinephrine was not detectable in any of the samples, but the standards were recovered. Tyramine values were not significantly different between the control group and the fought group, so tyramine does not appear to be important in agonistic behaviour. A comparison between the control and fought groups shows that fighting had an effect on the concentrations of octopamine, dopamine and 5-HT, but exercise only had an effect on octopamine levels, which showed a reduction from resting values in both winners and losers. Resting and post-fight concentrations of octopamine, dopamine and 5-HT were higher in winners than in losers. 5-HT concentration increased in the blood of fought crabs from resting values, whereas dopamine concentration decreased. In winners, octopamine concentrations decreased from resting values, but in losers octopamine levels increased from resting concentrations. The escalatory behaviour or intensity of fighting performed by winners and losers was related to dopamine levels but not to those of octopamine or 5-HT. Therefore, there appears to be a link between relative concentrations of these three amines (dopamine, octopamine and 5-HT) and fighting ability; the effects are not simply a result of activity. The better competitors have higher concentrations of these three amines at rest and after fighting. (+info)
Antagonism and accommodation: interpreting the relationship between public health and medicine in the United States during the 20th century.
Throughout the course of the 20th century, many observers have noted important tensions and antipathies between public health and medicine. At the same time, reformers have often called for better engagement and collaboration between the 2 fields. This article examines the history of the relationship between medicine and public health to examine how they developed as separate and often conflicting professions. The historical character of this relationship can be understood only in the context of institutional developments in professional education, the rise of the biomedical model of disease, and the epidemiologic transition from infectious disease to the predominance of systemic chronic diseases. Many problems in the contemporary burden of disease pose opportunities for effective collaborations between population-based and clinical interventions. A stronger alliance between public health and medicine through accommodation to a reductionist biomedicine, however, threatens to subvert public health's historical commitment to understanding and addressing the social roots of disease. (+info)
Clinical trial of a feline pheromone analogue for feline urine marking.
Thirty-six cases of feline urine marking problem were collected through the cooperation of veterinary practitioners in the Kanto, Chubu, and Kansai areas in Japan, for an assessment of the clinical effect of treatment with a synthetic analogue of a feline cheek gland pheromone-like product. The mean frequency of urine marking was 14.2 times/week (median, 10; range, 1-77) at pre-treatment week (preW), and decreased significantly from the first week of treatment, dropping to 4.2 times/week (median, 2; range, 0-44) at the fourth week of treatment. This effect continued until the fourth week after cessation of treatment. These 36 cases were divided into 3 groups based on the effectiveness of treatment as demonstrated in the fourth week of treatment; 37% was categorized as the totally eliminated group (urine marking was not seen), 40% as the reduced group (the frequency of urine marking was equal to or less than 50% that of the preW), and 23% as the unchanged group (the frequency of urine marking was more than 50% that of the preW). Effectiveness of treatment in these groups was 38%, 24%, and 38% at the fourth week after the cessation of treatment, respectively. The decreasing rate of urine marking was compared between cats with and without intercat aggression, and it was revealed that the frequency of marking was sustained at high level in cats with intercat aggression. These results suggest that this pheromone treatment is as effective in Japan as has been reported in other countries for solving feline urine marking problems. (+info)
Bullying behaviors among US youth: prevalence and association with psychosocial adjustment.
CONTEXT: Although violence among US youth is a current major concern, bullying is infrequently addressed and no national data on the prevalence of bullying are available. OBJECTIVES: To measure the prevalence of bullying behaviors among US youth and to determine the association of bullying and being bullied with indicators of psychosocial adjustment, including problem behavior, school adjustment, social/emotional adjustment, and parenting. DESIGN, SETTING, AND PARTICIPANTS: Analysis of data from a representative sample of 15 686 students in grades 6 through 10 in public and private schools throughout the United States who completed the World Health Organization's Health Behaviour in School-aged Children survey during the spring of 1998. MAIN OUTCOME MEASURE: Self-report of involvement in bullying and being bullied by others. RESULTS: A total of 29.9% of the sample reported moderate or frequent involvement in bullying, as a bully (13.0%), one who was bullied (10.6%), or both (6.3%). Males were more likely than females to be both perpetrators and targets of bullying. The frequency of bullying was higher among 6th- through 8th-grade students than among 9th- and 10th-grade students. Perpetrating and experiencing bullying were associated with poorer psychosocial adjustment (P<.001); however, different patterns of association occurred among bullies, those bullied, and those who both bullied others and were bullied themselves. CONCLUSIONS: The prevalence of bullying among US youth is substantial. Given the concurrent behavioral and emotional difficulties associated with bullying, as well as the potential long-term negative outcomes for these youth, the issue of bullying merits serious attention, both for future research and preventive intervention. (+info)
Anti-bullying interventions at school: aspects of programme adaptation and critical issues for further programme development.
Recently, a growing interest in problems at school of peer aggression and victimization was observed. As a result, intervention strategies appropriate for this kind of problem were required. The Norwegian anti-bullying intervention that was developed and evaluated by Olweus (1992) in the region of Bergen was considered to be a good model for other countries to implement interventions against peer aggression within the school environment. It was therefore adapted to the educational settings of other countries. This paper aims to discuss the adaptation processes of the Bergen anti-bullying programme and to give guidelines to advance further programme development. For this, the DFE Sheffield Bullying Project (Smith and Sharp, 1994), the Anti-bullying Intervention in Toronto schools (Pepler et al., 1994) and the Flemish anti-bullying project (Stevens and Van Oost, 1994) were considered in the analyses. Discussion of the adaptation processes of the Bergen model programme revealed that the adapted interventions largely succeeded in incorporating the core components of the Bergen model programme, taking into account the characteristics of the implementation environment. This suggests that for bully/victim interventions, the dilemma of programme fidelity and programme adaptation could be solved adequately. However, from a health promotion perspective, some critical issues for programme improvement were observed. Three suggestions for change were made, indicating that anti-bullying actions at schools may benefit from: (i) a clear overview of the learning objectives, specified per target population; (ii) more attention to parental involvement and family interventions; and (iii) additional information about the adoption processes of the anti-bullying interventions within schools. (+info)
The evolution of bourgeois, parasitic, and cooperative reproductive behaviors in fishes.
Among vertebrate classes, fishes exhibit by far the greatest variability in competitive and cooperative behaviors in male reproduction. Scramble competition between reproductive males is one possibility. Another possibility occurs when resources, mates, or locations can be monopolized, in which case males may invest in primary access to fertilizations by adopting a "bourgeois" strategy, or they may employ alternative mating tactics to evade the reproductive monopoly of other males. Adaptations in morphology, physiology, and behavior to bourgeois and alternative phenotypes are highly divergent. Here I review the functional characteristics that differ between bourgeois and parasitic phenotypes, and discuss the variability of alternative reproductive tactics at the levels of plasticity, determination, and selection. Examples will illustrate the importance of ecology, and will suggest that variation in reproductive tactics is largely adaptive. Behavioral solutions to competition for mates and fertilizations often involve agonistic behavior and conflict, but also cooperation among competitors (e.g., when subordinate males pay a price to bourgeois males for gaining access to fertilizable eggs). Application of molecular genetic tools has helped to uncover intricate sexual and social relationships in various fish species, including species that display some of the most complex reproductive and social patterns known among the vertebrates. (+info)
Competition for space among sessile marine invertebrates: changes in HSP70 expression in two Pacific cnidarians.
The role of stress proteins-either constitutive (HSC) or inducible (HSP)-of the HSP70 family in intra- and interspecific competition for space was examined in two sessile Pacific cnidarians. Anthopleura elegantissima, an intertidal anemone, and Corynactis californica, a subtidal corallimorpharian, express HSP70 in the absence of apparent physical stress. HSP70 protein expression is concentrated in the tentacles of A. elegantissima when the animal is exposed to contact with other benthic organisms. Under the same conditions, however, HSP concentrations are similar in the body and tentacles of C. californica. When two different clones of A. elegantissima interact in the field, the outside polyps (warriors) express more HSP70 than the inside ones (2.4 versus 0.6 ng HSP70/microg Protein). When different C. californica clones interact, HSP70 expression in the outside and inside polyps is similar (1.5 versus 1.8 ng HSP70/microg P) and is fairly constant in the corallimorpharian in the different interspecific encounters. HSP70 expression is related to the different kinds of aggression encountered by both cnidarians. HSP70 expression may be involved in the recovery of tissues damaged by the allelochemical, cytotoxical, or corrosive substances produced by different enemies. C. californica clones appear prepared for war, as evidenced by the high constant expression of HSP70 in the polyps. A. elegantissima exhibits differential HSP70 expression depending on the identity of each neighboring intra- or interspecific sessile competitor. We propose that stress proteins can be used to quantify space competition or aggression among sessile marine invertebrates. (+info)