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PubMed2004

[Changes in the expression of monoaminergic genes under the influence of repeated experience of agonistic interactions: from behavior to gene].

The role of genetic and environmental factors as well as brain neurochemistry in regulating aggressive and submissive behaviors in animals are considered. We present a review of data on changes in brain monoaminergic activity (synthesis, catabolism, receptors) and on the expression of monoaminergetic genes under repeated daily agonistic confrontations in male mice. A repeated experience of aggression was shown to result in the total activation of the dopaminergic system and the inhibition of the serotonergic one. This was accompanied by a decrease in the mRNA level of the catechol-O-methyltransferase gene in the midbrain and an increase of the mRNA level of the dopamine transporter and tyrosine hydroxylase genes in the ventral tegmental area of aggressive male mice. Repeated experience of social defeats produced dynamic changes in the serotonergic system of some brain areas and an increase of the mRNA level of the serotonin transporter and monoamine oxidase A genes in the midbrain raphe nuclei. Theoretical and methodological possibilities of the proposed ethological approach for studying molecular mechanisms of agonistic behavior are discussed in the context of the fundamental problem of investigating the ways of regulation from behavior to gene.

Animals↗
PubMed1984

Agonistic and reproductive interactions in Betta splendens.

Reproductive and agonistic behaviors in Siamese fighting fish were investigated in eight experiments, and some consequences and determinants of these sequences were isolated. First, fights and the formation of dominance-subordinancy relations were studied. Second, it was determined that large body size as well as males' prior residency in a tank produced an agonistic advantage; the magnitude of this advantage was positively related to the duration of residency. Third, the prior-residency effect in Bettas was determined by males' familiarity with visual and/or tactile cues in their home tanks. Fourth, dominant males had greater access to living space and were more likely to display at a mirror, build nests, and approach females than were subordinates. Finally, it was discovered that chemical cues associated with presumedly inert plastic tank dividers influence Bettas' social behavior.

Aggression↗
PubMed2000

Pavlovian feed-forward mechanisms in the control of social behavior.

The conceptual and investigative tools for the analysis of social behavior can be expanded by integrating biological theory, control systems theory, and Pavlovian conditioning. Biological theory has focused on the costs and benefits of social behavior from ecological and evolutionary perspectives. In contrast, control systems theory is concerned with how machines achieve a particular goal or purpose. The accurate operation of a system often requires feed-forward mechanisms that adjust system performance in anticipation of future inputs. Pavlovian conditioning is ideally suited to subserve this function in behavioral systems. Pavlovian mechanisms have been demonstrated in various aspects of sexual behavior, maternal lactation, and infant suckling. Pavlovian conditioning of agonistic behavior has been also reported, and Pavlovian processes may likewise be involved in social play and social grooming. Several further lines of evidence indicate that Pavlovian conditioning can increase the efficiency and effectiveness of social interactions, thereby improving their cost/benefit ratio. We extend Pavlovian concepts beyond the traditional domain of discrete secretory and other physiological reflexes to complex real-world behavioral interactions and apply abstract laboratory analyses of the mechanisms of associative learning to the daily challenges animals face as they interact with one another in their natural environments.

Aggression↗
PubMed1990

Bromocriptine-induced rotation: characterization using a striatal efferent lesion in the mouse.

Two lesion techniques were used to elucidate the mode of action of bromocriptine (BRC)-induced behavior in mice. With the first lesion, a unilateral 6-hydroxydopamine (6-OHDA) preparation, BRC administration resulted in contralateral rotation which was blocked by alpha-methyl-para-tyrosine (AMPT), comparable to previous reports using rats. After striatonigral/entopeduncular lesion, mice did not rotate in response to doses of BRC up to 30 mg/kg but did show general activation which was also inhibited by AMPT pretreatment. It is concluded that BRC does not elicit rotation when there is no dopaminergic asymmetry such as that caused by a unilateral 6-OHDA lesion or no asymmetry in the striatonigral or striatoentopeduncular efferents. Since BRC-induced behaviors are dependent on intact presynaptic dopamine and BRC is predominantly a D-2 agonist, behaviors elicited in response to BRC must be the result of coactivation of D-1 receptors by endogenous dopamine. Thus, the behavioral effects of BRC, and perhaps D-2 agonists in general, must be mediated by efferents other than the striatonigral and striatoentopeduncular pathways.

Animals↗
PubMed1982

Effect of telencephalon ablation on the reinforcing and eliciting properties of species-specific events in Betta splendens.

In male Betta splendens, aggressive behavior is drastically attenuated following telencephalon ablation. Because instrumental training and Pavlovian conditioning experiments with intact fish have suggested that associative factors may play an important role in the performance of agonistic behaviors, the effect of ablation on instrumental learning and Pavlovian conditioning was studied. In Experiment 1, ablation had no effect on the learning of the instrumental tunnel-swimming response reinforced by mirror presentation (i.e., viewing a conspecific), although the mirror presentations in yoked-control groups elicited fewer responses in ablates than in normal and sham-operated control fish. Yoked controls further established that instrumental responding was maintained by the reinforcement contingency and was not merely the result of increased motor activity. Experiment 2 studied Pavlovian conditioning of the components of the agonistic display. Unconditioned fin erection, gill erection, and tail beating (i.e., unconditioned responses, URs) to the mirror US all were less frequent in ablates than in normals or shams. Of these, only gill cover erection showed evidence of true conditioning (i.e., conditioned responses; CRs) in which responses to the conditioned stimulus (CS) are due to the pairings of CS and US (unconditioned stimulus). However, ablates suffered no impairment of conditioned gill erections. Ablates performed fewer fin erections to the CS; however, fin erection responses were not due to CS-US pairings but were attributable to pseudoconditioning. These results are related to hypotheses postulating the involvement of learning mechanisms in ablation-produced deficits and normal aggressive behavior.

Aggression↗
PubMed1982

Immature male and adult male interactions in bisexual langur (Presbytis entellus) troops.

One bisexual troop of langurs (Presbytis entellus) was intensively investigated for 32 months at the Junbesi-Ringmo study site in Nepal. Observations occurred during three separate studies and span a period of 6 years. All members of the study troop could be individually recognized throughout the three studies. During this investigation data were collected on immature male (from birth to 5 years of age) social relations with adult males. Social relations between these two classes of males varied both in type and in frequency of behaviors displayed. During the first study, when the troop was predominantly multi-male, young males directed various tense behaviors toward adult males. Monthly rates of occurrence of such behaviors fluctuated and showed a positive correlation with rates of agonistic behaviors between adult males. In contrast, interactions between the adult and immature males were considerably more relaxed during the second and third studies when the troop had but 1 adult male. Based on the results of these studies, and data evaluated from other studies of P. entellus, it is hypothesized that the frequency and patterning of interactions between adult males affect adult male relations with young males.

Age Factors↗
PubMed1997

Chemical communication, aggression, and conspecific recognition in the fish Nile tilapia.

The chemical modulation of agonistic behavior and conspecific recognition were tested in juveniles of the fish Nile tilapia, Oreochromis niloticus (L.). After a 7-day isolation period, the fish were grouped (four individuals per aquarium) for 7 days. Then fish of alpha and beta ranks (previously matched for similar size) were paired in a neutral territory for analysis of their agonistic interaction. Pairs composed of alpha and beta fish were established with either fish from the same group (familiar) or from two different groups (unfamiliar). The pairs were tested in contiguous compartments, either with water exchange between the compartments or in the absence of water exchange. In each condition the fish were separated by a transparent glass partition. Twelve pairs were tested in each experimental condition. Fish behavior was videotaped and the following variables were analyzed: (a) frequency of and time spent in agonistic patterns, (b) latency to start fighting, and (c) duration of swimming. Water exchange between compartments decreased agonistic interactions. This effect, however, was more pronounced in pairs of fish coming from the same group (in this case, subordinate fish spent less time in confrontations than dominant ones). We conclude that chemical communication decreases aggression in this species by (1) inducing an alarm reaction and (2) increasing conspecific recognition (thus stabilizing the dominance hierarchy).

Aggression↗
PubMed2006

Evolutionary background for stress-coping styles: relationships between physiological, behavioral, and cognitive traits in non-mammalian vertebrates.

Reactions to stress vary between individuals, and physiological and behavioral responses tend to be associated in distinct suites of correlated traits, often termed stress-coping styles. In mammals, individuals exhibiting divergent stress-coping styles also appear to exhibit intrinsic differences in cognitive processing. A connection between physiology, behavior, and cognition was also recently demonstrated in strains of rainbow trout (Oncorhynchus mykiss) selected for consistently high or low cortisol responses to stress. The low-responsive (LR) strain display longer retention of a conditioned response, and tend to show proactive behaviors such as enhanced aggression, social dominance, and rapid resumption of feed intake after stress. Differences in brain monoamine neurochemistry have also been reported in these lines. In comparative studies, experiments with the lizard Anolis carolinensis reveal connections between monoaminergic activity in limbic structures, proactive behavior in novel environments, and the establishment of social status via agonistic behavior. Together these observations suggest that within-species diversity of physiological, behavioral and cognitive correlates of stress responsiveness is maintained by natural selection throughout the vertebrate sub-phylum.

Adaptation, Psychological↗
PubMed1987

Family system and individual child correlates of sibling behavior.

In this study of the connections between marital adjustment and sibling behavior, the best predictor of younger siblings' prosocial behavior was found to be low interparental conflict. Older siblings' prosocial behavior was most associated with the mothers' marital adjustment. Younger siblings' agonistic behavior was related to marital adjustment and to the older children's activity level.

Child↗
PubMed1991

Visual perception of texture in aggressive behavior of Betta splendens.

In order to elucidate the role of texture in fish vision, the agonistic behavior of male Siamese fighting fish (Betta splendens) was tested in a response to models composed by means of image processing techniques. Using the models with the contour shape of a side view of Betta splendens in an aggressive state, the responses were vigorous when there was a fine distribution of brightness and naturalistic color, producing textures like a scale pattern. Reactions became weaker as the brightness and color distribution reverted to more homogeneous levels and the scale pattern disappeared. When the artificial models with the circular contour shape were used, models with the scale pattern evoked more aggressive behaviors than those without it, while the existence of spherical gradation affected the behavior slightly. These results suggest that texture plays an important role in fish visual perception.

Aggression↗
PubMedDate not supplied

Long-term effects of developmental exposure to zidovudine on exploratory behavior and novelty discrimination in CD-1 mice.

Long-term changes in exploratory, social and agonistic behavior have been reported in rodents following developmental exposure to zidovudine (AZT), an agent commonly administered to pregnant seropositive women and their neonates to prevent HIV-1 transmission. The present study evaluates the effects of either prenatal or prolonged AZT treatment on spatial and nonspatial novelty discrimination in mice, using an open-field test with four objects, in which responses to both spatial rearrangement of familiar objects and object novelty are assessed. AZT (160 mg/kg) or Saline was given orally twice daily to pregnant mice from gestational days (GD) 10 to 19 (Experiment 1) or from GD 10 to lactation day 10 (Experiment 2). Offspring of both sexes were tested on postnatal day (PND) 28, 45 or 70. Depending on treatment schedule, AZT altered different behavioral responses, males being more affected than females. The prenatal treatment (Experiment 1) reduced exploration of the objects at all ages considered and increased wall and top rearing at ages 45 and 70. Following prolonged treatment (Experiment 2), AZT offspring were markedly more active than controls and displayed more wall rearing at age 70 while showing lower grooming frequency at all ages. Both AZT and control mice failed to respond to object rearrangement at adulthood, a discrepancy from previous data, which is discussed in relation to perinatal stress effects.

Age Factors↗
PubMed1976

Effects of chronic d-amphetamine on social behavior of the rat: implications for an animal model of paranoid schizophrenia.

Hooded rats in a social colony were given increasing daily doses of d-amphetamine up to 8 mg/kg. Time-lapse 16 mm cinematographically recorded behavior was analyzed for the following: grooming, feeding, sex, sleeping, resting, sterotypy, agonistic behavior, muricidal activity, and the location and movement of each rat. Subordiant rats receiving d-amphetamine actively withdrew from social interactions by retreating to strategically defensible locations in the environment. They remained hypervigilant of other rats and overreacted to their approaches by either fleeing or by defensively rearing and "boxing". On the other hand, when the dominant rat received the maximum dose, it seemed totally oblivious to the other rats. The responses to drug treatment in subordinant rats may provide a model for the social behavior of frightened paranoid schizophrenics.

Animals↗
PubMed2005

Aggressive behavior increases after termination of chronic sildenafil treatment in mice.

Recent reports to the U.S. Food and Drug Administration Adverse Event Reporting System implicate sildenafil citrate in adverse emotional and aggressive behaviors. Sildenafil citrate (Viagra) is widely prescribed for erectile dysfunction and acts by inhibiting phosphodiesterase Type-5, resulting in accumulation of cyclic-guanosine monophosphate (cGMP). Cyclic-GMP is synthesized by guanylyl cyclase that is directly activated by the messenger molecule, nitric oxide (NO), formed throughout the CNS by the enzyme nitric oxide synthase (NOS). Elevated concentrations of cGMP have been associated with increased aggressive behavior. In addition, the potential effect of cGMP accumulation on NO-mediated behavioral and neuroendocrine function through possible feedback mechanisms remains unspecified; however, neuronal NOS (nNOS) inhibition by pharmacologic agents or ablation of the gene encoding nNOS increases aggressive behavior in male mice. We tested the hypothesis that sildenafil citrate may increase aggression via its actions on cGMP and potential feedback inhibition of NO concentrations. Male C57BL/6 mice were injected with saline vehicle (0), 2, 5, 8, or 10 mg/kg of sildenafil citrate thrice weekly for 4 weeks. Latency to display aggressive behavior, frequency, and duration of aggressive behavior were recorded during neutral-arena aggression tests. No change in agonistic behavior was observed in mice during treatment with sildenafil citrate. However, sildenafil-treated mice given the highest dose were generally more aggressive 1 week post-cessation of drug treatment as compared to vehicle-treated mice. Additional investigation into potential withdrawal effects or abuse doses seems warranted.

Aggression↗
PubMed1997

Integrative functions of lactational hormones in social behavior and stress management.

For mammalian reproduction to succeed, self-defense and asociality must be subjugated to positive social behaviors, at least during birth, lactation, and sexual behavior. Perhaps the important task of regulating the interaction between social and agonistic behaviors is managed, in part, by interactions between two related neurochemical systems that incorporate oxytocin and vasopressin in their functions. The neuropeptides oxytocin and vasopressin participate in important reproductive functions, such as parturition and lactation, and homeostatic responses, including modulation of the adrenal axis. Recent evidence also implicates these hormones in social aspects of reproductive behaviors. For example, oxytocin is important for a variety of positive social behaviors, including the regulation of maternal-infant interactions. In adult animals, oxytocin may facilitate both social contact and selective social interactions associated with social attachment and pair bonding, and it participates in the regulation of parasympathetic functions. Vasopressin, in contrast, is associated with behaviors that might be broadly classified as "defensive" including enhanced arousal, attention, or vigilance, increased aggressive behavior, and a general increase in sympathetic functions. On the basis of the literature on the functions of these hormones and our own recent findings, we propose that dynamic interactions between oxytocin and vasopressin are components of a larger system which integrates the neuroendocrine and autonomic changes associated with mammalian social behaviors and the concurrent regulation of the stress axis. In addition, studies of lactating females provide a valuable model for understanding the more general neuroendocrinology of the stress axis. Peptide hormones, including oxytocin and vasopressin, do not readily cross the blood-brain barrier and must be administered centrally (i.c.v.) to reach the brain. Nasal sprays have been used to promote milk let down and have been used in some behavioral studies, but the extent to which such compounds reach the brain is not known. Therefore, virtually nothing is known regarding the effects in humans of centrally administered oxytocin. The study of human lactation, in conjunction with animal research, provides an opportunity to begin to develop viable hypotheses regarding the behavioral effects of oxytocin.

Adrenal Glands↗
PubMed1981

Photosensitization and the nervous system in the planarian Dugesia gonocephala. A histochemical, ultrastructural and behavioral investigation.

Photosensitization phenomena may be induced in planarias by eosin and hematoporphyrin, and as a result, dopamine agonistic behavior ("screw-like hyperkinesia") is set up in the animal. Histochemical, ultrastructural and pharmacological investigations have shown that this hyperkinesia is of post-synaptic origin in eosin photosensitization, and of pre-synaptic origin in hematoporphyrin photosensitization. The authors suggest an hypothesis to explain the different activity of the two photosensitizers, and discuss the validity of the experiment with regard to human porphyria.

Animals↗
PubMed1990

Novel quinuclidine-based ligands for the muscarinic cholinergic receptor.

Recent clinical studies on Alzheimer's patients have implied that only agents displaying high efficacy at the cortical muscarinic receptor have yielded encouraging results. This paper describes the design, synthesis, and biochemical characterization of novel quinuclidine-based muscarinic agonists which can readily penetrate into the central nervous system and which are capable of displaying high efficacy at cortical sites. With use of a biochemical assay capable of measuring receptor affinity and predicting cortical efficacy, it has been discovered that an oxadiazole ring and related heterocycles can function as bioisosteric replacements for the ester moiety found in several known muscarinic ligands. Within this series there exist compounds which span the efficacy range from high-efficacy agonist through partial agonists to antagonists with affinity comparable or superior to that of classical quaternary ammonium ligands. Consistent with recent molecular biology studies, structure-activity trends are interpreted in terms of separate binding sites for agonists and antagonists with H-bonding interactions characterizing agonist behavior and lipophilic binding characterizing antagonist behavior. Thus the aminooxadiazole moiety has structural features which are optimized for an agonist profile.

Animals↗
PubMed1995

MK-801 reverses effects of chronic levodopa on D1 and D2 dopamine agonist-induced rotational behavior.

The effect of dizocilpine (MK-801) on dopaminergic agonist-induced rotational behavior was investigated in rats with 6-hydroxydopamine lesions of the nigrostriatal pathway after chronic administration of levodopa. The rotational response to the D2 agonist quinpirole was markedly increased in levodopa-treated animals compared with rats chronically administered saline. The increase in responsiveness to quinpirole was reversed by co-administered MK-801. Conversely, the rotational response to the D1 agonist SKF 38393 was reduced following chronic treatment with levodopa. The decrease in response to SKF 38393 was also reversed by MK-801. Chronic treatment with levodopa failed to alter the rotational responses to two other D1 preferring agonists SKF 81297 and SKF 82968, but responses to both agonists were increased by the co-administration of MK-801. These data support the hypothesis the MK-801 may reverse the differential changes in D1 and D2 agonist-induced motor responses which result from chronic treatment with levodopa.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1995

Organization of projections from the medial nucleus of the amygdala: a PHAL study in the rat.

The organization of axonal projections from the four recognized parts of the medial amygdalar nucleus (MEA) were characterized with the Phaesolus vulgaris leucoagglutinin (PHAL) method in male rats. The results indicate that the MEA consists of two major divisions, ventral and dorsal, and that the former may also consist of rostral and caudal regions. As a whole, the MEA generates centrifugal projections to several parts of the accessory and main olfactory sensory pathways, and projections to a) several parts of the intrahippocampal circuit (ventrally); b) the ventral striatum, ventral pallidum, and bed nuclei of the stria terminalis (BST) in the basal telencephaon; c) many parts of the hypothalamus; d) midline and medial parts of the thalamus; and e) the periaqueductal gray, ventral tegmental area, and midbrain raphé. The dorsal division of the MEA (the posterodorsal part) is characterized by projections to the principal nucleus of the BST, and to the anteroventral periventricular, medial, and central parts of the medial preoptic, and ventral premammillary hypothalamic nuclei. These hypothalamic nuclei project heavily to neuroendocrine and autonomic-related parts of the hypothalamic periventricular zone. The ventral division of the MEA (the anterodorsal, anteroventral, and posteroventral parts) is characterized by dense projections to the transverse and interfascicular nuclei of the BST, and to the lateral part of the medial preoptic, anterior hypothalamic, and ventromedial hypothalamic nuclei. However, dorsal regions of the ventral division provide rather dense inputs to the medial preoptic region and capsule of the ventromedial nucleus, whereas ventral regions of the ventral division preferentially innervate the anterior hypothalamic, dorsomedial, and ventral parts of the ventromedial nuclei. Functional evidence suggests that circuits associated with dorsal regions of the ventral division may deal with reproductive behavior, whereas circuits associated with ventral regions of the ventral division may deal preferentially with agonistic behavior.

Amygdala↗