Ethopharmacological studies of the effects of β-carbolines and benzodiazepines on murine aggression

The behavioral profiles generated by a benzodiazepine (BDZ) agonist (diazepam), an “inverse” agonist (β-carboline-3-carboxylate ethyl ester, βC-3-CEE), and dihydro-(DHβCs) and tetrahydro-β-carbolines (THβCs) were investigated on aggressive isolated mice using a computerized ethopharmacological technique. Augmentation of intraspecific sociability with a concurrent reduction of aggression are characteristic features of diazepam's effects, whereas βC-3-CEE exerts the opposite effects. βC-3-CEE countered the prosocial activity of diazepam and had intrinsic activities on intraspecific behaviour. Some DHβCs (harmalol and 6-methoxy-harmalan) and THβCs (1-methyl-6-hydroxy-THβC and tetrahydronorharmane) may exacerbate aggression at low (BDZ-negative) doses (1 mg/kg), and inhibit such behavior at higher (serotonin-positive) doses (10-15 mg/kg). The ethological profiles of DHβCs were different from the profiles of THβCs. Differences in ethological profiles of βC-3-CEE, DHβCs, and THβCs seem to reflect the neurochemical (mainly BDZ-and serotonergic) properties of these substances.     

Role of female aggression in prevention of infanticidal behavior in male common voles,Microtus arvalis (Pallas, 1779)

Infanticidal behavior of male common voles (Microtus arvalis) was investigated in relation to the age of unfamiliar pups. Sires from 18 pairs were removed after parturition of their offspring and replaced by unfamiliar males at different ages of the neonates. In group 1, containing six females with their offspring, the new male was introduced into the females' cages on day 1 after the parturition. In group 2 the new male was introduced on day 5 after parturition and in group 3 on day 9 after parturition. The male was removed after 3 days and the neonates recounted. Male common voles killed up to 100% of the neonates in litters containing neonates younger than 9 days by rapid bites to the head of the neonates (groups 1 and 2, mortality rates of 0.86 and 0.38). However, with older pups, a mortality rate of 0.06 was observed while 33% of the intruder males showed signs of injuries (group 3). These findings show that infanticidal behavior of male common voles represents one factor of pup mortality. The results are discussed in relation to changes in the degree of maternal aggression and in the context of the social system of the common vole for solving the conflict between postpartum estrous mating and infanticidal behavior of male common voles. Aggr. Behav. 23:293–298, 1997. © 1997 Wiley-Liss, Inc.     

Pre-breeding aggression in male and female three-spined sticklebacks (gasterosteus aculeatus)

The reactions of 34 female and 32 male three-spined sticklebacks to a conspecific were observed in the month before the breeding season. Factor analysis indicated that the organization of the response in the two sexes was very similar; in both cases, axes labelled “aggression,” “threat,” “curiosity,” and “sex” emerged, with male fish having significantly higher scores on the first factor and females on the second. Any theory of the causes of aggression in sticklebacks should accommodate these facts.     

Effects of neonatal treatment with cyproterone acetate on aggressive behavior induced by footshock in adult male rats

High levels of androgens are required to organize aggressive behavior in adult male rats. Footshock-induced aggression was tested in Wistar rats allocated to one of three experimental groups: control (oil-injected) males (M), males neonatally injected with the antiandrogen cyproterone acetate (CA), and males treated as in the CA group but gonadectomized just before puberty (CAG). An antiaggressive effect of CA in those adult male rats neonatally treated with this compound was found. Neonatal exposure to cyproterone acetate exerts an antiandrogenic effect over the expression of shock-induced aggressive behavior. The behavioral effects of CA were not countered by adult treatment with testosterone propionate.     

肌肉上瘾综合征:一种新型的心理障碍?

肌肉上瘾综合征是指个体对于缺乏大块肌肉的错误认知的先占观念,是近二十年来西方学者的研究热点之一。已有研究从肌肉上瘾的诊断和测量,与体象障碍等心理障碍和行为异常的关系,以及形成机制等方面进行了深入的研究。然而,目前关于其临床诊断、产生机制等方面还存在争议。肌肉上瘾综合征在我国,甚至是亚洲尚缺乏足够的关注度。肌肉上瘾综合征的诊断依据、病征的文化差异、共患疾病、形成机制等将成为今后研究的焦点问题。     

Offensive and defensive bite-target topographies in attacks by lactating rats

The attacks by resident lactating Wistar rats on sexually naive conspecifics of both sexes were examined. Male and female intruders were equally attacked in terms of frequency and number of bites, but the topographies of biting seen in these encounters were different. Similarly to male-male agonistic interactions, females were attacked in a fashion which avoided bites to the head and snout (“offensive” attack), whereas males were frequently bitten on such vulnerable regions (“defensive” attack). This dichotomy in bite pattern suggests that different motivations and functions underlay maternal aggression in these situations. The defensive attack on males may be a deterrent to infanticide since only male intruders counterattack lactating females and kill their pups. The attack on females may be concerned with resource competition.     

Analysis of the targets and tactics of conspecific attack and predatory attack in northern grasshopper mice onychomys leucogaster

Comparisons of tactics of fighting between species are often difficult to make since the body targets attacked may differ. Thus it becomes difficult to assess whether differences in fighting tactics are due to species-specific differences in the tactics themselves or due to the different targets attacked. A solution to this problem is to analyse the tactics of a species that attacks different targets under different circumstances. In this way, differences in tactics can be more readily attributed to differences in targets. In this study, resident male northern grasshopper mice (Onychomys leucogaster) were tested against intruding male conspecifics and against laboratory mice (Mus musculus domesticus). Conspecifics were mainly bitten on the lower dorsum, whereas prey were bitten and killed by bites to the nape of the neck. Therefore, it was possible to analyze the tactics of attack by grasshopper mice when attacking different body targets. For example, in order to defend the lower dorsum and the nape, both intruding conspecifics and prey adopted an upright defensive posture. Resident grasshopper mice used the lateral attack tactic to gain access to the lower flanks but not the nape. This illustrates that the lateral attack tactic is not merely a tactic suitable for overcoming the upright defense tactic, but is used in this context only when the target attacked is on the opponent's posterior dorsum. Such withinpecies comparison enables the identification of the contextual rules which govern the use of fighting tactics. © 1992 Wiley-Liss, Inc.     

Effects of acute administration of nicotine and lobeline on agonistic encounters in male mice

The effects of acute administration of two nicotinic ligands, (‐)‐nicotine and (‐)‐lobeline were examined on isolation‐induced aggression in mice. Individually housed male mice confronted anosmic “standard opponents” in a neutral arena 10 min after drug administration. Encounters were videotaped and evaluated using an ethologically based analysis facilitating estimation of time allocated to 11 broad behavioral categories. Nicotine did not have significant effects on threat or attack but significantly diminished time allocated to digging. The lowest dose of lobeline significantly diminished attack and induced a slight increase of immobility without significantly diminishing other behaviors with motor components. The intermediate and highest dose of lobeline reduced time allocated to all behaviors with motor components. It is concluded that these two nicotinic agonists produce different behavioral profiles during agonistic encounters in mice but that this test may not facilitate assessing the impact of such drugs on irritability. Aggr. Behav. 26:376–385, 2000. © 2000 Wiley‐Liss, Inc.     

A developmental-genetic analysis of aggressive behavior in mice: IV. Genotype-environment interaction

To assess the extent of plasticity in behavioral development after directional selection for aggressive behavior, male mice were reared and tested in selected social rearing and testing conditions. After four generations of selective breeding, the lines differed in all attack measures when tested in a dyadic assessment following isolation rearing. Line-specific effects of isolation vs. group rearing were demonstrated, and longitudinal studies showed the ontogenetic pattern of difference between lines to be substantially changed by conditions of rearing and testing. The social-interactional processes that might produce the developmental genotype-environment interaction were investigated. Line-specific interaction patterns within long-established sibling groups predicted aggressive behavior in cross-situational dyadic assessments. Group rearing attenuated most line differences in aggressive measures, but the high-aggressive line was more likely than the low-aggressive line to persist in attacking over consecutive days of observation. Cross-fostering in early development did not significantly change adult aggressive behavior. Some implications of a developmental-genetic approach to the study of social interactions are discussed.     

Theological and Ethical Reflections on Men and Violence: Toward a New Understanding of Masculinity

Abstract

This paper explores the reasons why men express violence against women, children and other men, suggesting that men's violence represents one of the darkest features of masculinity. The way men are socialized and conditioned requires and produces violent behaviors that are destructive to men themselves as well as to women, children, and the earth. The author proposes the need to re-envision masculinity to enable men and women to create communities in which people are encouraged to participate in ‘adventurous partnering for peace’.