Copulatory and Agonistic Behavior in Syrian Hamsters Following Social Defeat

Abstract

Syrian hamsters are highly aggressive animals that reliably defend their home territory. After social defeat, however, hamsters no longer defend their home cage but instead display submissive and defensive behavior toward an intruder, a response that we have termed conditioned defeat. Plasma testosterone is significantly reduced in Syrian hamsters following repeated defeat suggesting that social defeat might also impair copulatory behavior. The present study aimed to determine whether copulatory behavior in male Syrian hamsters is suppressed following repeated social defeats and additionally whether exposure to a hormone-primed stimulus female after social defeat reduces the behavioral response to defeat. Hamsters were paired with an aggressive opponent for one or nine defeats using a resident-intruder model, while controls were placed into the empty cage of a resident aggressor. On the day after the last treatment, half of the hamsters were paired with a receptive female for 10 min. There were no significant differences in the copulatory behavior of defeated versus non-defeated hamsters, and the opportunity to copulate had no effect on subsequent conditioned defeat testing, as defeated animals displayed significantly more submissive behavior than did non-defeated animals. The current data suggest that conditioned defeat is not necessarily a maladaptive response to social stress, at least in terms of reproductive behavior, but may instead represent a viable behavioral strategy adopted by losing animals following social defeat. Further, these data indicate that conditioned defeat is relatively persistent and stable, as the opportunity to copulate does not reduce the subsequent display of submissive behavior.

Chronic social stress in puberty alters appetitive male sexual behavior and neural metabolic activity

“…The lack of effect on the consummation of male sexual behavior is consistent with recent studies in adult hamsters (Jeffress and Huhman, 2013). In adults, conditioned defeat which is characterized by a long-lasting inhibition of aggression toward smaller intruders (Huhman et al, 2003) and lowered testosterone levels (Huhman et al, 1991) does not affect male sexual behavior, as these animals are still capable of mating with females.…”

Stress, sex, and motivated behaviors

“…The normal response in this context is aggressive behavior, so this inappropriate submissive behavior has been referred to as conditioned defeat (Jasnow and Huhman, 2001). Similar changes are observed after multiple episodes of defeat (Huhman et al, 2003;Morrison et al, 2011Morrison et al, , 2014Jeffress and Huhman, 2013). Repeated episodes of defeat add a different dimension both in total amount of stress experienced and in predictability.…”

Evaluation of the anti-depressant potential of metformin in conditioned defeat model in golden Syrian hamsters

“…Flow of procedure followed in conditioned defeat model has been depicted in Figure 1. [14][15][16][17] The smaller (loser) hamsters were evaluated for behaviour after the experiment on day 0 and every third day using the OFT, noting how much time was spent in the central zone and how many times the central line was crossed using Aithal YR et al Int J Basic Clin Pharmacol. 2023 Jul;12(4):515-521 Mazemaster 2.0 software.…”