Functional dichotomy within the vomeronasal system: distinct zones of neuronal activity in the accessory olfactory bulb correlate with sex-specific behaviors.
(25/2225)
Chemosensory neurons in the vomeronasal organ (VNO) detect pheromones that elicit social and reproductive behaviors in most terrestrial vertebrates. Vomeronasal receptor neurons are chemoarchitecturally divided into two populations based on their position in the VNO, the type of G-protein subunit expressed, the family of putative pheromone receptor expressed, and termination site of their axons in the accessory olfactory bulb (AOB). To investigate the functional implications of these two segregated VNO-AOB pathways, we stimulated mice with pheromonal cues associated with different behavioral contexts and examined cellular activation patterns in the AOB. Exposure of ICR male mice to BALB/c males resulted in aggressive behavior, accompanied by a VNO-dependent increase in c-fos immunoreactivity in a cluster of cells located almost exclusively in the caudal AOB in both strains. This caudal cluster of activated cells did not appear to require the overt display of aggressive behavior because it was present in both the dominant and submissive males and could be evoked when the stimulus animal was anesthetized. In contrast, exposure of an ICR male to an ICR female in diestrus resulted in activation of cells located predominantly in the rostral AOB. Our findings indicate that male-to-male interactions involving interstrain recognition activate a separate population of vomeronasal receptor neurons than chemosensory cues detected in a sexual context. The results suggest that the dichotomy in the peripheral vomeronasal system serves to separate pheromones based on the behaviors they drive. As such, the results provide a bioassay for identifying pheromone molecules. (+info)
Developmental exposure to vasopressin increases aggression in adult prairie voles.
(26/2225)
Although the biological roots of aggression have been the source of intense debate, the precise physiological mechanisms responsible for aggression remain poorly understood. In most species, aggression is more common in males than females; thus, gonadal hormones have been a focal point for research in this field. Although gonadal hormones have been shown to influence the expression of aggression, in many cases aggression can continue after castration, indicating that testicular steroids are not completely essential for the expression of aggression. Recently, the mammalian neuropeptide arginine vasopressin (AVP) has been implicated in aggression. AVP plays a particularly important role in social behavior in monogamous mammals, such as prairie voles (Microtus ochrogaster). In turn, the effects of social experiences may be mediated by neuropeptides, including AVP. For example, sexually naive prairie voles are rarely aggressive. However, 24 h after the onset of mating, males of this species become significantly aggressive toward strangers. Likewise, in adult male prairie voles, central (intracerebroventricular) injections of AVP can significantly increase intermale aggression, suggesting a role for AVP in the expression of postcopulatory aggression in adult male prairie voles. In this paper, we demonstrate that early postnatal exposure to AVP can have long-lasting effects on the tendency to show aggression, producing levels of aggression in sexually naive, adult male prairie voles that are comparable to those levels observed after mating. Females showed less aggression and were less responsive to exogenous AVP, but the capacity of an AVP V(1a) receptor antagonist to block female aggression also implicates AVP in the development of female aggression. (+info)
Survival of reproductive behaviors in estrogen receptor beta gene-deficient (betaERKO) male and female mice.
(27/2225)
Previously, it was shown that the lack of a functional estrogen receptor (ER) alpha gene (ERalpha) greatly affects reproduction-related behaviors in both female and male mice. However, widespread expression of a novel second ER gene, ERbeta, demanded that we examine the possible participation of ERbeta in regulation of these behaviors. In dramatic contrast to our results with ERalpha knockout (alphaERKO) males, betaERKO males performed at least as well as wild-type controls in sexual behavior tests. Moreover, not only did betaERKO males exhibit normal male-typical aggressive behavior, including offensive attacks, but they also showed higher levels of aggression than wild-type mice under certain conditions of social experience. These data revealed a significant interaction between genotype and social experience with respect to aggressive behavior. Finally, females lacking a functional beta isoform of the ER gene showed normal lordosis and courtship behaviors, extending in some cases beyond the day of behavioral estrus. These results highlight the importance of ERalpha for the normal expression of natural reproductive behaviors in both sexes and also provide a background for future studies evaluating ERbeta gene contributions to other, nonreproductive behaviors. (+info)
Aftermath of war experience: impact of anxiety and aggressive feelings on the group and the therapist.
(28/2225)
AIM: Analysis of some anxious and aggressive features stemming from the highly traumatic war experiences and having as a consequence chronic posttraumatic stress disorder (PTSD). METHOD: Group psychotherapy was applied as a therapeutic approach of choice. RESULTS: During the psychotherapeutic process, the possibility to name and express anxiety and aggressiveness was uncovered not only as the sequels of highly traumatic war experiences but even the transgenerational transmission of frustrations and aggressive feelings. These features have constantly very strong influence on the therapist's countertransference. Some of the most prominent characteristics of these processes are described through clinical vignettes. CONCLUSION: Longer group psychotherapy is required for patients suffering from serious PTSD to develop the possibility to externalize their deep traumas and to work them through in order to reestablish connections with everyday life. During that process, the countertransferential issues disclose the most important traumatic features and encapsulations, and indicate the main topics to be addressed in patients and the therapist as well. (+info)
Violence in the emergency department: a survey of health care workers.
(29/2225)
BACKGROUND: Violence in the workplace is an ill-defined and underreported concern for health care workers. The objectives of this study were to examine perceived levels of violence in the emergency department, to obtain health care workers' definitions of violence, to determine the effect of violence on health care workers and to determine coping mechanisms and potential preventive strategies. METHODS: A retrospective written survey of all 163 emergency department employees working in 1996 at an urban inner-city tertiary care centre in Vancouver. The survey elicited demographic information, personal definition of violence, severity of violence, degree of stress as a result of violence and estimate of the number of encounters with violence in the workplace in 1996. The authors examined the effects of violence on job performance and job satisfaction, and reviewed coping and potential preventive strategies. RESULTS: Of the 163 staff, 106 (65%) completed the survey. A total of 68% (70/103) reported an increased frequency of violence over time, and 60% (64/106) reported an increased severity. Most of the respondents felt that violence included witnessing verbal abuse (76%) and witnessing physical threats or assaults (86%). Sixty respondents (57%) were physically assaulted in 1996. Overall, 51 respondents (48%) reported impaired job performance for the rest of the shift or the rest of the week after an incident of violence. Seventy-seven respondents (73%) were afraid of patients as a result of violence, almost half (49%) hid their identities from patients, and 78 (74%) had reduced job satisfaction. Over one-fourth of the respondents (27/101) took days off because of violence. Of the 18 respondents no longer working in the emergency department, 12 (67%) reported that they had left the job at least partly owing to violence. Twenty-four-hour security and a workshop on violence prevention strategies were felt to be the most useful potential interventions. Physical exercise, sleep and the company of family and friends were the most frequent coping strategies. INTERPRETATION: Violence in the emergency department is frequent and has a substantial effect on staff well-being and job satisfaction. (+info)
Aggression patterns and speciation.
(30/2225)
The evolutionary significance of interspecific aggression as a factor in speciation was tested among three chromosome forms of the actively speciating fossorial rodent Spalax ehrenbergi in Israel. Laboratory experiments testing intra- and interspecific aggression were conducted on 48 adult animals from 10 populations comprising three chromosome forms with 2n = 52, 58, and 60. Twelve agonistic, motivational-conflict, and territorial behavioral variables were recorded during 72 combats involving homo- and heter-ogametic encounters between opponents. Analysis of the data matrix was carried out by the nonmetric multivariate Smallest Space Analysis (SSA-II). The results indicate that (a) aggression patterns, involving agonistic conflict and territorial variables, are higher in heterogametic encounters than in homogametic ones; and (b) aggression is higher between contiguous chromosome forms (2n = 58-60, and 2n = 52-58) than between noncontiguous ones (2n = 52-60). Both a and b suggest that high interspecific aggression appears to be adaptively selected at final stages of speciation in mole rats as a premating isolating mechanism which reinforces species identification and establishes parapatric distributions between the evolving species. (+info)
S18327 (1-[2-[4-(6-fluoro-1, 2-benzisoxazol-3-yl)piperid-1-yl]ethyl]3-phenyl imidazolin-2-one), a novel, potential antipsychotic displaying marked antagonist properties at alpha(1)- and alpha(2)-adrenergic receptors: II. Functional profile and a multiparametric comparison with haloperidol, clozapine, and 11 other antipsychotic agents.
(31/2225)
S18327 was dose-dependently active in several models of potential antipsychotic activity involving dopaminergic hyperactivity: inhibition of apomorphine-induced climbing in mice, of cocaine- and amphetamine-induced hyperlocomotion in rats, and of conditioned avoidance responses in rats. Furthermore, reflecting its high affinity at serotonin(2A) sites, S18327 potently blocked phencyclidine-induced locomotion and 1-[2, 5-dimethoxy-4-iodophenyl]-2-aminopropane-induced head-twitches in rats. In models of glutamatergic hypoactivity, S18327 blocked hyperlocomotion and spontaneous tail-flicks elicited by the N-methyl-D-aspartate antagonist dizocilpine. The actions of S18327, together with its binding profile at multiple monoaminergic receptors (15 parameters in total), were compared with those of clozapine, haloperidol, and 11 other antipsychotics by multiparametric analysis, and the resulting dendrogram positioned S18327 close to clozapine. Consistent with a clopazine-like profile, S18327 generalized to a clozapine discriminative stimulus and evoked latent inhibition in rats, blocked aggression in isolated mice, and displayed anxiolytic properties in the ultrasonic vocalization and Vogel procedures in rats. Relative to the above paradigms, only markedly (>20-fold) higher doses of S18327 were active in models predictive of potential extrapyramidal side effects: induction of catalepsy and prolactin secretion, and inhibition of methylphenidate-induced gnawing in rats. S18327 showed only modest affinity for histaminic and muscarinic receptors. Multiparametric analysis of these data distinguished S18327 from both haloperidol (high extrapyramidal potential) and clozapine (high histaminic and muscarinic affinity). In conclusion, S18327 displays a broad-based pattern of potential antipsychotic activity at doses appreciably lower than those eliciting extrapyramidal side effects. In this respect, S18327 closely resembles clozapine, but it is chemically distinct and displays weak affinity for histaminic and muscarinic receptors. (+info)
Hate, projective identification, and the Psychotherapist's struggle.
(32/2225)
The relationship between projective identification and aggression is explored through case material in which the psychotherapist felt strongly influenced by the patient's projections. Through a variety of interpersonal and intrapsychic dynamics, the patient evoked an unconscious and conscious sense of hate in the psychotherapist that emerged in a countertransference dream. (+info)