Social defeat and subsequent isolation housing affect behavior as well as cell proliferation and cell survival in the brains of male greater long-tailed hamsters

Abstract

Aversive social interactions, such as social defeat, can alter a variety of behavioral and cognitive functions. In the present study, we examined the effects of social defeat and the subsequent housing on behavior as well as cell proliferation and cell survival in the solitary, male greater long-tailed hamster (Tscheskia triton). We found that three days of agonistic interactions reliably led to a subordinate-dominant relationship between pairs of male hamsters. However, such behavioral interactions did not alter cell proliferation in any of the brain areas examined. In addition, subordinate males housed in close proximity to the dominant male (separated by a wire screen) following social defeat did not display differences in agonistic behaviors, but had enhanced cell proliferation in the anterior hypothalamus, ventromedial hypothalamus (VMH), and amygdala as well as increased cell survival in the VMH, compared to subordinate males that were housed individually. Together, our data indicate distinct effects of agonistic interactions and the social housing condition on behavior as well as cell proliferation and survival in the brain of the greater long-tailed hamster.

Keywords: BrdU; Ki67; aggression; amygdala; hypothalamus; social isolation.