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We examined the relative influences of pre-fight housing condition, contest intensity, and contest outcome in modulating post-fight stress hormone concentrations in territorial male convict cichlids (Archocentrus nigrofasciatus). Individuals were housed either in isolation or in semi-natural communal tanks. Pairs of male cichlids that differed considerably(More)
The present study investigated the hypothesis that social isolation increases aggression by increasing the number of V1a vasopressin receptors in the anterior hypothalamus (AH). Male hamsters were randomly assigned to a group that was allowed to interact with a small nonaggressive hamster three times each week for 3 weeks (socially experienced) or to a(More)
Male sexual behavior is mediated in part by androgens, but in several species, mating is also influenced by estradiol formed locally in the brain by the aromatization of testosterone. The role of testosterone aromatization in the copulatory behavior of male Syrian hamsters is unclear because prior studies are equivocal. Therefore, the present study tested(More)
Arginine vasopressin (AVP) regulates aggression in male Syrian hamsters. In this study, we used radioligand receptor autoradiography to examine whether changes in agonistic behavior following acute and repeated social defeat are accompanied by changes in AVP V1a receptor binding. Social defeat produced high levels of submissive behavior and a loss of(More)
Less than 60% of infants undergoing invasive procedures in the neonatal intensive care unit receive analgesic therapy. These infants show long-term decreases in pain sensitivity and cortisol reactivity. In rats, we have previously shown that inflammatory pain experienced on the day of birth significantly decreases adult somatosensory thresholds and(More)
In Syrian hamsters, vasopressin (AVP) controls a form of scent marking called flank marking. Microinjection and lesion studies have identified several components of the neural circuit controlling this behavior. Microinjection of AVP into the medial preoptic-anterior hypothalamus (MPOA-AH), lateral septal nucleus (LS), bed nucleus of stria terminalis (BNST),(More)
Arginine-vasopressin (AVP) is critical for the expression of a variety of social behaviors in many species. Previous studies have demonstrated that AVP regulates behaviors such as social communication and aggression in Syrian hamsters through the V1a receptor subtype. In male hamsters, AVP injected into the anterior hypothalamus (AH) stimulates aggression,(More)
The present study investigated the effect of social status in Long-Evans hooded rats established during food competition on V(1a) vasopressin receptor (V(1a)R) binding in the lateral septum (LS), medial preoptic area (MPOA), bed nucleus of the stria terminalis (BNST), anterior hypothalamus (AH), and central/basolateral amygdala (CeB). Serum concentration of(More)
We have reported that there is a sex difference in the behavioral response to social defeat in hamsters. While previously defeated male hamsters fail to display normal territorial aggression and instead produce submissive/defensive behavior, a phenomenon that we have termed conditioned defeat (CD), only a small portion of previously defeated females exhibit(More)
The mammalian circadian clock can be entrained by photic and nonphotic environmental time cues. gamma-aminobutyric acid (GABA) is a nonphotic stimulus that induces phase advances in the circadian clock during the middle of the subjective day. Several nonphotic stimuli suppress Period 1- and Period 2 mRNA expression in the suprachiasmatic nucleus (SCN);(More)