Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Agonistic Behavior”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1993

Differential effects of chronic dopamine D1 and D2 receptor agonists on rotational behavior and dopamine receptor binding.

The effects of chronic continuous and intermittent administration of the dopamine D1 receptor agonist SKF 38393 or the D2 receptor agonist quinpirole on rotational behavior and dopamine receptor binding were examined in rats with a unilateral 6-hydroxydopamine lesion of the nigrostriatal pathway. Continuous and intermittent SKF 38393 both decreased the rotational response to subsequent challenge with SKF 38393. Intermittent SKF 38393 increased quinpirole rotation, while continuous SKF 38393 had no effect. Continuous administration of quinpirole did not affect rotation elicited by either SKF 38393 or quinpirole. Intermittent quinpirole, however, increased both SKF 38393- and quinpirole-induced rotation. Autoradiographic techniques were used to measure D1 receptor binding in striatum and substantia nigra pars reticulata and D2 receptor binding in striatum and nucleus accumbens. Intermittent SKF 38393 reduced D1 receptor Bmax and increased D1 Kd in the striatum, while both continuous and intermittent treatment with the D1 agonist decreased D1 binding in the substantia nigra pars reticulata. Intermittent quinpirole decreased D1 receptor Kd in striatum, and continuous quinpirole reduced D1 binding slightly in substantia nigra pars reticulata. Striatal D2 receptor binding was unaffected by treatment with either SKF 38393 or quinpirole. Intermittent SKF 38393 and continuous quinpirole both reversed the lesioned-induced elevation in D2 binding in the nucleus accumbens, while intermittent quinpirole decreased D2 binding in the accumbens on both the intact and denervated sides. Thus, the effects of chronic treatment with D1 and D2 agonists on behavioral responses to D1 and D2 receptor stimulation differed considerably and were dependent on the treatment regimen employed.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Effects of single restraint on the defensive behavior of male and female rats.

The effects of single aversive stimulation due to restraint (RT) on behavioral responses to unfamiliar conspecifics were studied in male and female rats. The Resident-intruder paradigm was adopted, RT animals and their controls playing the role of intruders. Introductory and agonistic behaviors of both intruders and residents were recorded. In males, RT increased both the number of subjects which showed freezing and freezing duration, and this was independent of the amount of aggression received by the residents. By contrast, no change was found in active defense. Increased passive defense was not paralleled by a complete inhibition of aggression. The latter was rare, but not absent, and occurred in RT males as often as in their controls. Females never showed freezing and, unlike males, resorted to a fully active defensive strategy. RT females were the preferential targets of residents' high-intensity aggression, but showed the same rate of defensive responding as control females. The crucial role played in studies of social behavior by testing conditions and mutual influences between the behavior of experimental subjects and residents are discussed.

Aggression↗
PubMed2007

Social housing conditions around puberty determine later changes in plasma cortisol levels and behavior.

A recent study found that male guinea pigs raised in large, mixed age/sex groups exhibited an unexpected suppression of their cortisol response at 4 mo of age. The present study examined the effect of social experience around the time of puberty on cortisol response suppression and social behavior at 4 mo of age. Males reared in large, mixed age/sex groups were either pair-housed with a female or moved to another large colony at 55 days of age. When tested at 4 mo, pair-housed males exhibited much higher levels of courtship and sexual behavior than did colony-housed males, and a shorter latency to begin courtship when with an unfamiliar adult female. In addition, pair-housed males showed much higher levels of agonistic behavior and a shorter latency to escalated aggression with an unfamiliar adult male. Pair-housed males also had lower basal cortisol concentrations and exhibited a greater increment in cortisol levels when isolated in a novel cage than did colony-housed males. Finally, pair-housed males showed a smaller increment in cortisol levels when with the stimulus female or male than when isolated, but colony-housed males did not. The findings demonstrate that social housing conditions around the time of puberty can have pervasive effects on social behavior and hypothalamic-pituitary-adrenal (HPA) activity in 4-mo-old males. Further, these findings are consistent with the notion that changes in HPA activity contribute to social behavior development beyond the time of sexual maturity.

Adaptation, Physiological↗
PubMed2000

Effects of selected serotonin 5-HT(1) and 5-HT(2) receptor agonists on feeding behavior: possible mechanisms of action.

Serotonin (5-HT) receptor agonists with high affinity for the different subtypes (i.e. 5-HT(1A-1F), 5-HT(2A-2C)) of the 5-HT(1)- and 5-HT(2) receptor families have been shown to affect ingestive behavior. It has been assumed that: (1) stimulation of hypothalamic 5-HT(2C) or 5-HT(1B) receptors leads to a behaviorally specific hypophagic effect by accelerating satiety processes; (2) stimulation of 5-HT(2A) receptors leads to a disruption of the feeding cascade; and (3) stimulation of 5-HT(1A) and 5-HT(2B) receptors leads to a hyperphagic effect. The present paper reviews studies performed with the relatively selective receptor agonists ipsapirone (5-HT(1A)), CP-94,253 (5-HT(1B)), BW 723C86 (5-HT(2B)) and ORG 37684 (5-HT(2C)), as well as the nonselective receptor agonists TFMPP (5-HT(1B/2C)), m-CPP (5-HT(2C/1B)) and DOI (5-HT(2A/2C)) in a variety of feeding paradigms in rats, both after systemic and local injection. These studies support a role for other neuroanatomical regions (i.e. brain stem) and behavioral mechanisms (i.e. appetitive processes) in the hypophagic effects of these compounds, possibly as a function of the administered dose. Studies with 5-HT receptor antagonists indicate that the proposed role of particular 5-HT(1/2) receptor subtypes in the hypophagic effects of these 5-HT receptor agonists may be more complicated than originally thought. Further characterization of the role of 5-HT(1/2) receptor subtypes in the control of ingestive behavior will require extensive pharmacological and behavioral studies, using more selective receptor agonists and antagonists and different behavioral procedures, as well as verification in transgenic animals.

Animals↗
PubMed2006

The effect of buspirone on normal and hypoarousal-driven abnormal aggression in rats.

Aggressiveness is associated with decreased glucocorticoid production, autonomic hypoarousal, and social deficits in antisocial personality disorder and its childhood antecedent conduct disorder. We showed previously that experimentally induced chronic glucocorticoid deficiency leads to abnormal forms of attack, autonomic hypoarousal, and social deficits in rats. We also showed that serotonergic neurotransmission, which downregulates aggressiveness in normal rats appears to lose its aggression-controlling role in glucocorticoid-deficient rats. We suggested that abnormal aggression develops in such rats as a consequence of serotonergic disturbances that result from chronic glucocorticoid deficiency. Here we assessed the effects of the serotonergic anxiolytic buspirone on aggressive behavior in normal and glucocorticoid-deficient rats. Noteworthy, this compound is frequently used in the clinic to control moderate aggression problems. As expected, buspirone dose-dependently reduced the duration of agonistic behaviors in normal rats exposed to resident/intruder conflicts. Similar to earlier experiments, glucocorticoid deficiency dramatically increased the share of attacks directed towards vulnerable body parts of the opponents (head, throat and belly). Surprisingly, 1 and 5 mg/kg buspirone dramatically increased the frequency of biting attacks in glucocorticoid-deficient rats. The share of vulnerable attacks remained as high as in vehicle-treated glucocorticoid-deficient rats. These data show that chronic glucocorticoid deficiency disturbs serotonergic neurotransmission, which reverses the aggression-related effects of the serotonergic agent buspirone. This finding is in line with disparate human findings on the effects of serotonergic agents on aggression in antisocial personality disordered people.

Adrenalectomy↗
PubMed1998

Biphasic effects of anandamide.

Effects of the endogenous cannabimimetic anandamide were assessed over a wide dose range in a series of physiological and behavioral assays. These included the tetrad of tests in mice commonly used to assess cannabinoid-induced effects (motor activity, ring catalepsy, hypothermia, and analgesia tests), as well as a model for agonistic behavior on dyadic interactions of singly housed males with nonaggressive group-housed partners. Anandamide-induced effects on leukocyte phagocytosis were measured in a chemiluminescence assay. Results indicated that the higher doses tested (10-100 mg/kg) produced the well-known inhibitory effects in all of the above parameters as well as inhibition of phagocytosis. The lowest dose of anandamide tested (0.01 mg/kg) stimulated behavioral activities in the open field, on the ring and aggressive behavior in timid singly housed mice. This dose of 0.01 mg/kg, also stimulated phagocytosis. We suggest several possible mechanisms to explain these findings such as a differential involvement of a Gs and a Gi protein activated at low and high doses, respectively, allosteric modulation of the cannabinoid, and activation of presynaptic cannabinoid receptors by low doses of anandamide.

Aggression↗
PubMed1997

Acute and subchronic effects of tiapride on isolation-induced aggression in male mice.

Although the antiaggressive properties of several atypical neuroleptics are known, the actions of tiapride (a selective dopaminergic D2-receptor antagonist) on agonistic behavior have not been explored and there are no studies comparing acute and subchronic effects of this compound on aggression in rodents. In this work, the effects of tiapride (20-100 mg/kg, IP), administered acutely or subchronically for 10 days, on agonistic behaviour elicited by isolation in male mice were examined. Individually housed mice were exposed to anosmic "standard opponents" 30 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. Tiapride decreased time spent in offenssive behaviors significantly, without an impairment of motor activity (60 and 80 mg/kg). Moreover, no tolerance to tiapride antiaggressive activity was observed after repeated administration of the drug. On the contrary, the action on immobility showed a clear tolerance development with repeated injections (100 mg/kg). The divergence found in the temporal course of tolerance to tiapride in its antiaggressive and motor effects is discussed.

Aggression↗
PubMed1977

Paternal effects on the development of social behavior in Mus musculus.

In order to extend the determination and description of effects of the father's phenotype on the development of social behavior in male mice, we tested 24 males from each of 2 highly inbred strains of Mus musculus, A/J and C57BL/6J. Approximately 1 week before the birth of the subjects, we replaced natural fathers with a foster parent such that, within each strain, 8 subjects had preweaning experience with same-strain males, 8 with other-strain males, and 8 with same-strain females, in addition to their natural mothers. Observations of social behavior were conducted at 21, 50, and 60 days of age. The results showed effects of the foster parent's phenotype on the development of social exploration in both strains and, possibly, on agonistic behavior in C57BL/6J mice. The different effects in the 2 strains indicate mechanisms dependent on genotype.

Aggression↗
PubMed1998

Mesolimbic component of the ascending cholinergic pathways: electrophysiological-pharmacological study.

The cholinergic input from the pontomesencephalic cholinergic neurons to the diencephalic and basal forebrain structures has been implicated in a number of limbically controlled overt behaviors. The cellular mechanism by which the cholinergic terminals initiate behavioral manifestations is not clear. The objective of this study was to investigate the effects of the ascending cholinergic projection from the laterodorsal tegmental nucleus (LDT) on neuronal firing in the anterior hypothalamic-medial preoptic region (AHMP), known to be involved in agonistic behavior. Experiments were performed on urethan-anesthetized rats. Iontophoretic application of carbachol (CCh) into the vicinity of single cells in the AHMP caused a dose-dependent decrease in the mean firing rate of 83% of units and an increase in 10% of units. The inhibitory effect of CCh, but not the excitatory effect, was reversed by iontophoretic pretreatment with scopolamine. The inhibition of the firing rate was repeatable for the same dose of CCh and dose dependent. Electrical stimulation of neurons in the LDT caused a comparable, current-dependent decrease in the mean firing rate of AHMP neurons that also was reversed by pretreatment of neurons in the AHMP with scopolamine. The antagonizing effects of scopolamine were reversible with time. The same units in the AHMP that inhibited their firing to stimulation of the LDT also responded with a similar inhibition to local iontophoretic CCh. Finally, the fluorescent carbocyanine dye, 4-(4-(dihexadecylamino)styryl)-N-methylpyridinium iodide, (DiA), has been used as a retrograde axonal tracer and was injected into the recording sites immediately after the electrophysiological recordings. After 1 wk, DiA dye was found in numerous neurons in the LDT as shown by the fluorescence confocal microscopy. Results of the study suggest that LDT cholinergic neurons project and terminate in the AHMP and that their activation causes a decrease in the mean firing rate of the AHMP neurons. It is postulated that this inhibitory effect is implicated in the initiation of some of the behavioral patterns like defensive or alarm vocalization and behavioral inhibition.

Acetylcholine↗
PubMed1984

Functional alterations in the social organization of bonnet macaques (Macaca radiata) induced by ovariectomy: an experimental analysis.

A group of seven ovariectomized female and three intact male Macaca radiata was compared to a matched control group of intact females and males during a breeding season. A second, replicate, experiment was conducted after the males had been switched between groups to partially control for seasonal effects and differences in the age of males. In the first experiment, 161 hr of quantitative data were collected and in the second, 93 hr. Differences in the social organization of the experimental and control groups were anticipated by five a priori evolutionary predictions focused on aspects of intersexual and intrasexual selection: (1) less affiliative and sexual behavior between males and ovariectomized females; (2) less intrasexual competition between them; (3) more intrasexual affiliation among males and ovariectomized females; (4) more intersexual competition between them and (5) more homogeneous patterns of use of resources. Sixty of 90 applications of these predictions to behavioral measures were confirmed. These admittedly exploratory a priori predictions thus significantly increased the ability to anticipate social consequences of female castration. Contrary to Predictions 2 and 4, ovariectomized females engaged in more intrasexual agonistic behavior and less frequently showed aggression toward males.

Animals↗
PubMed1995

Effects of neonatal testicular suppression with a GnRH antagonist on social behavior in group-living juvenile rhesus monkeys.

Twenty-four male and eight female 1-year-old rhesus monkeys (Macaca mulatta) were observed for social interaction with other yearlings and with their mothers. The males comprised three groups which differed in the level of neonatal androgen exposure. One group received the GnRH antagonist Antide during their first four neonatal months (Antide n = 8), which suppressed pituitary LH secretion resulting in peak neonatal T levels < 0.7 nmol/liter. A second group received Antide treatment combined with a long-lasting testosterone replacement (Ant/And n = 8), which resulted in peak neonatal T levels of 29.1 +/- 3.8 nmol/liter. The third group (Vehicle n = 8) received the Antide and androgen vehicles and had intermediate peak T levels of 5.2 +/- 1.0 nmol/liter. Behavior of males was compared to that of unmanipulated control females living in the same social group (Control Female n = 8) when androgen levels were uniformly low (< 0.7 nmol/liter) in all male groups. Subjects received 12 weekly 30-min focal observations by an observer blind to the neonatal treatments. Marked sex differences were found in several categories of sociosexual behavior. All three groups of males engaged in significantly more sexual and play behavior than females, with the exception of quiet solitary play, which females exhibited significantly more frequently In addition, females exhibited significantly more interest in infants than did any male group. There were no differences between groups in agonistic behavior or time spent in contact with other individuals, but females spent significantly more time than any male group in proximity to other animals. Both females and Antide males initiated proximity and followed animals significantly more frequently than Ant/And males, but not Vehicle males. Proximity durations with mothers initiated and terminated by yearlings were longer for females than for any male group and for Antide males than for Ant/and males. Antide males were groomed significantly longer than any other group. These results demonstrate effects of neonatal testosterone exposure on social behavior in yearling rhesus. Suppression of neonatal T did not affect sexually dimorphic patterns of play and sexual behavior, but altered the character of interactions with their mothers. Whether this reflects a delay in the development of maternal independence or a fundamental alteration in patterns of social interaction remains to be resolved.

Age Factors↗
PubMed1997

Social stress, depression, and brain dopamine in female cynomolgus monkeys.

Socially subordinate adult female cynomolgus monkeys are hypercortisolemic, the targets of aggression, fearful, vigilant, receive little positive affiliative contact, exhibit pathological behaviors indicating anxiety, and are disengaged in the social events around them. Subordinates also have altered dopaminergic activity that may be due to decreased D2 receptor binding. Dopaminergic activity indices were more closely associated with affiliative than agonistic behaviors.

Aggression↗
PubMed2003

Female sex pheromone-mediated effects on behavior and consequences of male competition in the shore crab (Carcinus maenas).

Exposure to receptive female pheromone elicits guarding behavior in shore crab males (Carcinus maenas), but little is known about the effects of sex pheromone on male competition or if the female plays an active role in mate choice. This study examined whether female pheromone enhanced agonistic behavior between males and what effects visual and chemical cues had on the rules and costs of such contests. We also investigated whether females exhibit a preference for males in terms of size. Under laboratory conditions, solitary male shore crabs engaged males who already had possession of a female. The visual and chemical presence of a receptive female had an impact on contest rules and costs. Fights were costly in terms of duration and of sustaining injury with either one or both crabs incurring injury in 40% of fights. To investigate the metabolic consequences of fighting over a perceived sexual resource (chemical cue only), fights were staged between pairs of size-matched males in the presence of water containing the female sex pheromone, water in which males had been kept, and untreated seawater. The duration and intensity of contests were greater when staged in the presence of the female pheromone compared with the two other treatments. Crabs that fought in the presence of female sex pheromone also had a greater accumulation of L-lactate and a reduction of glycogen stores. Fights were less costly in terms of injury with a single chemical cue compared with enhanced costs with a multiple sexual cue. The importance of female choice was determined by presenting postmolt females with different sized males. Males were kept in a fixed position, and the majority of females approached and performed courtship behavior to the largest males, demonstrating that females may be selective in terms of size.

Aggression↗
PubMed1998

Growth hormone increases aggressive behavior in juvenile rainbow trout.

The aim of the present study was to clarify the role of growth hormone in social interactions in juvenile salmonids. Growth hormone increases the metabolic demands and feeding motivation in teleost fish. As a consequence, growth hormone may increase aggression levels and/or fighting ability. To test these hypotheses we observed agonistic behavior in pairs of juvenile rainbow trout (Oncorhynchus mykiss) consisting of two control fish (C/C pairs), two growth hormone-treated fish (GH/GH pairs), or one growth hormone-treated and one control fish (C/GH pairs). The initiator and the winner of each act of aggression were registered. Aggression was lowest in the C/C pairs, intermediate in the C/GH pairs, and highest in the GH/GH pairs, with the difference between the C/C pairs and the GH/GH pairs being significant. This supports the hypothesis that GH increases aggression levels. However, in the C/GH pairs, the number of conflicts won by GH-treated and control fish did not differ significantly. Thus, because social status was not increased, GH did not appear to affect fighting ability. We suggest that growth hormone affects aggression indirectly by increasing the swimming activity, and/or by inducing defense of a larger territory, thereby increasing the encounter rate between opponents. Since increased aggression can incur energetic and mortality costs, there may be selection against high GH levels in natural populations.

Aggression↗
PubMed2001

20-hydroxyecdysone causes increased aggressiveness in female American lobsters, Homarus americanus.

Lobsters become transiently more aggressive before ecdysis. This aggressiveness accompanies an increase in hemolymph titers of 20-hydroxyecdysone (20-HE). Combats between intermolt female lobsters, injected with premolt levels of 20-HE, and larger, saline-injected opponents were videotaped. Aggressive, defensive, and avoidance behaviors were ranked according to aggressiveness in a Rank of Aggression hierarchy, which included opponent-directed and (nonopponent) redirected behaviors. Treated animals performed more and more highly aggressive behaviors than saline-injected controls. Opponents of treated animals performed fewer aggressive behaviors than saline-injected control opponents. Controls performed more defensive behaviors than treated animals, when redirected behaviors were considered. Differences in avoidance behaviors among the four types of combatants were not significant. The total aggressive content was the same in treated and control fights, but the interactions between combatants in the two fights were significantly different. Treated animals were equally as aggressive and defensive as their opponents; controls were relatively less aggressive and more defensive than their opponents. These results correlate with molt-cycle variations in behavior, 20-HE titers, and the effects of 20-HE and molt-differentiated hemolymph on the claw opener muscle. They suggest that 20-HE orchestrates intrinsic, cellular, and nuclear events that produce the molt-cycle transformations in agonistic behavior and aggressive state of lobsters.

Aggression↗
PubMed1997

Interaction of morphine and haloperidol on agonistic and motor behaviors of male mice.

To further clarify the interaction between opioid and dopaminergic systems, the effects of simultaneous administration of morphine hydrochloride (1.25 or 2.5 mg/kg) and haloperidol (0.1 mg/kg) on aggressive behavior of male mice were explored. Isolated male mice (experimental animals) were confronted in a neutral area with anosmic, group-housed consepecifics (standard opponents) 30 min after injection of both compounds, and aggression was evaluated by estimation of times allocated to 11 different behavioral categories. In the first experiment (which functioned as a pilot study), the two doses of morphine were explored. In the second one, incorporating a more complete experimental design, only the lowest morphine dose was used and the animals were preselected by a previous aggression test. In attack behavior, morphine added to haloperidol counteracted, at least partially, the antiaggressive effect of the neuroleptic. In contrast, the impairing effects of haloperidol on motor activity were increased by the addition of morphine. These results show that the behavioral effects of dopaminergic antagonists are modulated by opioid influences and that opiates and dopaminergic agents interact in a different manner on motor and on aggressive behaviors.

Agonistic Behavior↗
PubMed2003

Similarities in affiliation and aggression between cross-fostered rhesus macaque females and their biological mothers.

In female-bonded primate species, there is cross-generational consistency in female affiliative and aggressive behavior. This consistency could be the result of maternal effects, offspring learning, shared environment, and/or direct genetic inheritance of behavioral or psychological traits. In this study, I investigated possible similarities in affiliation and aggression between cross-fostered rhesus macaque females and their biological mothers. Ten female infants were cross-fostered at birth, and selected aspects of their affiliative and agonistic behavior over the course of their first 3 years of life were compared to the behavior of their foster and biological mothers. Average offspring rates of social contact and aggression across the 3 years, and in particular in Years 2 and 3, resembled those of their biological mothers whereas no clear behavioral similarities between offspring and foster mothers were observed at any age. Heritable variation in female social behavior may be maintained by natural selection and leads to adaptation to different socioecological niches within macque populations.

Aggression↗
PubMed2000

Human 5-hydroxytryptamine(5A) receptors activate coexpressed G(i) and G(o) proteins in Spodoptera frugiperda 9 cells.

The ability of the human 5-hydroxytryptamine serotonin type 5A (h5-ht(5A)) receptor to couple to G proteins from distinct families was investigated through the simultaneous infection of Spodoptera frugiperda 9 insect cells with recombinant baculoviruses encoding the various proteins. Expression of G proteins was demonstrated in immunoblots. Receptor-G protein coupling was monitored by high-affinity agonist binding and agonist-induced stimulation of [(35)S]guanosine-5'-O-(3-thio) triphosphate binding to membranes. Receptors expressed alone displayed low-affinity agonist binding, and endogenous G proteins were only poorly stimulated on the addition of 5-hydroxytryptamine. When receptors were coexpressed with mammalian G(i)/G(o) proteins (Galpha(i) or Galpha(o) plus Gbeta(1)gamma(2)), the coupled phenotype was achieved: agonists bound with high affinity in a guanosine-5'-(beta, gamma-imido)triphosphate-sensitive manner and stimulated [(35)S]guanosine-5'-O-(3-thio)triphosphate binding to high levels. These effects were not observed on coexpression with G(z)/G(s)/G(q/11/16) or G(12/13). Various ligands were evaluated for their agonistic, antagonistic, or inverse agonistic behavior in both receptor binding and activation assays. Although G(o) displayed different receptor coupling characteristics than G(i) proteins, no clear coupling preference was evident. Coexpression of receptors and Galpha(i) subunits without Gbeta(1)gamma(2) produced increases in both agonist affinity and maximum G protein activation that were smaller than those in the presence of Gbeta(1)gamma(2), suggesting that Gbeta(1)gamma(2) coexpression improves receptor-G protein coupling. Similarly, coexpression of receptors with Gbeta(1)gamma(2) alone resulted in an improved interaction with endogenous G proteins. Our results demonstrate that h5-ht(5A) receptors expressed in Spodoptera frugiperda 9 cells selectively and functionally couple to coexpressed mammalian G(i) and G(o) proteins.

Animals↗