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 145 records · Page 8Linked to original sources

Neural connections of the anterior hypothalamus and agonistic behavior in golden hamsters.

In male golden hamsters, offensive aggression is regulated by an interaction between arginine-vasopressin and serotonin at the level of the anterior hypothalamus. The present studies were conducted to study a neural network underlying this interaction. The connections of the anterior hypothalamus were examined by retrograde and anterograde tracing in adult male hamsters. Several limbic areas were found to contain both types of tracing suggesting reciprocal connections with the anterior hypothalamus. Their functional significance relating to the consummation of aggression was tested by comparing neuronal activity (examined through quantification of c-Fos-immunolabeling) in two groups of animals. Experimental animals were sacrificed after attacking an intruder. Control animals were sacrificed after exposure to a woodblock carrying the odor of an intruder that elicited behaviors related to offensive aggression without its consummation. An increased density of Fos-immunoreactivity was found in experimental animals within the medial amygdaloid nucleus, ventrolateral hypothalamus, bed nucleus of the stria terminalis and dorsolateral part of the midbrain central gray. These data suggest that these areas are integrated in a neural network centered on the anterior hypothalamus and involved in the consummation of offensive aggression. Finally, c-Fos-immunoreactivity was combined with labeling of serotonin and vasopressin neurons to identify sub-populations particularly associated with offensive aggression. Vasopressin neurons in the nucleus circularis and medial division of the supraoptic nucleus showed increased neuronal activity in the fighters, supporting their role in the control of offensive aggression.

Aggression↗

Social behavior and aggressive problems of cats.

Cats form social groups in which individuals recognize each other, and the cohesiveness of the group is maintained by a variety of amicable behaviors. Agonistic behavior may occur between group members and between group members and nongroup members. Within the domestic environment, agonistic behavior may become a problem when it is directed at housemates or humans. Differential diagnosis and treatment of various problems of aggressive behavior are discussed.

Aggression↗

Antiaggressive and motor effects of haloperidol show different temporal patterns in the development of tolerance.

The study of the temporal course of tolerance development was used as a means to separate different aspects of the action of haloperidol on social behavior. Agonistic behavior was studied in isolated male mice that confronted standard opponents (anosmic and grouped conspecifics) in a neutral area. The aggressive and motor behaviors of the experimental animals were evaluated 30 min or 24 h either after a single injection of haloperidol (0.4 mg/kg) or following the last of a series of 15 or 30 injections. When animals were evaluated 30 min after the haloperidol injection, no tolerance to the antiaggressive effects was evident. The action on immobility, on the contrary, showed a clear tolerance development with repeated drug administration, both with 15 and 30 injections. When evaluated 24 h after the last injection, tolerance to the antiaggressive effects developed with repeated injections. Increased immobility was never found in the tests carried out after 24 h, not even in the single injection group. The clear divergence found in the temporal courses of tolerance to haloperidol in its antiaggressive and motor effects suggests that these actions are mediated through different neurophysiological mechanisms. A parallel with extrapyramidal and therapeutic effects is discussed.

Aggression↗

Dimeric pentapeptide enkephalin: a novel probe of delta opiate receptors.

A dimeric pentapeptide enkephalin (DPE2) consisting of two molecules of [D-Ala 2, Leu 5] enkephalin linked at C-terminal leucine with ethylenediamine, (H-Tyr-D-Ala-Gly-Phe-Leu-NH-Ch2)2 is a bivalent ligand for the delta enkephalin receptors of rat brain and neuroblastoma-glioma hybrid (NG108-15) cells. This new enkephalin analog shows dramatically increased affinity in radioligand assays using whole brain membranes when delta but not mu specific radioligands are employed. When membranes from NG108-15 cells are used, the dimer shows greatly increased activity irrespective of the mu or delta specificity of the tracer. The dimer DPE2 shows a four-fold, "sodium shift" in its IC50 for competition with [3H]naloxone, suggestive of agonist behavior. Agonist activity was confirmed by demonstrating that DPE2 inhibits cyclic AMP production in prostaglandin E1 stimulated NG108-15 cells, and by demonstrating very high potency in the mouse vas deferens bioassay. DPE2 binds to the same delta sites as the delta-selective monomer [D-Ala2, D-Leu5] enkephalin, since the two ligands show complete crossdisplacement. Radiolabeled 3H-DPE2 shows a five-fold higher affinity constant, a 2.5-fold higher association rate constant, and a two-fold lower dissociation rate than the monomer. These results are consistent with the hypothesis that the dimeric pentapeptide enkephalin can bridge two delta receptors. This enkephalin dimer provides a valuable new probe of opiate receptors and their organization in cell membranes.

Animals↗

Behavioral analysis of kanamycin administration to mice.

The present series of experiments investigated behavioral changes in HET mice following administration of kanamycin, one of the aminoglycoside antibiotics. After drug treatment, HET mice showed changes in complex behaviors, including male agonistic behavior, female postpartum aggression, and tactile discrimination performance. Specifically, the temporal distribution of agonistic behavior appears to be affected by kanamycin treatment in both males and females, and kanamycin administration seems to alter reversal performance on a tactile discrimination task. These findings suggest the need for more careful examination of behaviors which may prove to be sensitive indices of antibiotic toxicity.

Aggression↗

Vasopressin interactions with oxytocin in the control of female sexual behavior.

Previous studies have found that central administration of arginine vasopressin and arginine vasopressin receptor V1a antagonists respectively inhibited and stimulated receptivity but did not examine effects on other aspects of female sexual behavior. Central oxytocin facilitates both proceptive and receptive components of sexual behavior and diminishes male-directed agonistic behavior. The present study examined i.c.v.-administered arginine vasopressin and V1a antagonist effects on proceptive, receptive and agonistic behaviors, and interactions with oxytocin. In experiment 1, rats were primed s.c. with 2 microg estradiol benzoate x 2 days and with 500 microg of progesterone on day 3. Arginine vasopressin (0.2, 0.4 microg) or normal saline vehicle was administered 5 h after progesterone treatment and sexual and agonistic behavior measured 30, 60 and 90 min later. Compared with saline, both doses of arginine vasopressin significantly decreased lordosis responses to mounting and hop-dart proceptive behavior and trended toward significantly increasing agonistic behaviors. In experiment 2, oxytocin (2 microg) infusion just after arginine vasopressin (0.4 microg) significantly increased lordoses and decreased agonistic behaviors but did not affect hopping and darting. In experiment 3, conducted in ovariectomized rats primed with estradiol benzoate (1 microg/day s.c. x 2 days), i.c.v. infusion of 0.5 and 1.0 microg of the selective V1a antagonist, d(CH2)5Tyr-(Me)arginine vasopressin on day 3 significantly increased lordoses and trended toward increasing hopping and darting 4 and 6 h after i.c.v. treatment. In experiment 4, 1 microg of the selective oxytocin antagonist, d(CH2)5[Tyr(Me)2, Thr4, Tyr-NH2(9)]OVT given 1 h before d(CH2)5Tyr-(Me)arginine vasopressin (1 microg) significantly decreased lordoses. Previous studies indicate that arginine vasopressin contributes to light phase inhibition of female sexual behavior. Our findings suggest that arginine vasopressin may exert this effect through interactions that decrease oxytocin stimulation of sexual behavior and raise the question whether sex steroid conditions that stimulate sexual behavior may suppress central arginine vasopressin and V1a receptor activity.

Animals↗

Behavioral profile of raclopride in agonistic encounters between male mice.

Raclopride is a substituted benzamide with high selectivity as an antagonist of central dopaminergic D2 receptors and potential antipsychotic effects. In comparison with a classic DA receptor blocking agent like haloperidol, raclopride displays an atypical profile in preclinical tests for extrapyramidal side effects. Antiaggressive properties of raclopride on agonistic behavior have not yet been fully explored. In this work the effects of raclopride (0.1, 0.3, or 0.6 mg/kg) on aggressive and motor behaviors in male mice were studied. Aggression tests were performed 30 min after injections. Encounters were videotaped and behavior was evaluated, measuring the time spent in 11 broad categories of behavior. The results show a clear antiaggressive effect of raclopride, with very little motor impairment and some increase in exploratory behavior. This behavioral profile is very similar to the one observed with other atypical neuroleptics and differs somewhat from that found in the classic compounds.

Agonistic Behavior↗

Chemical communication in scarab beetles: reciprocal behavioral agonist-antagonist activities of chiral pheromones.

A novel mechanism of reciprocal behavioral agonist-antagonist activities of enantiomeric pheromones plays a pivotal role in overcoming the signal-to-noise problem derived from the use of a single-constituent pheromone system in scarab beetles. Female Anomala osakana produce (S, Z)-5-(+)-(1-decenyl)oxacyclopentan-2-one, which is highly attractive to males; the response is completely inhibited even by 5% of its antipode. These two enantiomers have reverse roles in the Popillia japonica sex pheromone system. Chiral GC-electroantennographic detector experiments suggest that A. osakana and P. japonica have both R and S receptors that are responsible for behavioral agonist and antagonist responses.

Animal Communication↗