Social environment determines the long-term effects of social defeat

BDNF Overexpression in the Ventral Tegmental Area Prolongs Social Defeat Stress-induced Cross-Sensitization to Amphetamine and Increases ΔFosB Expression in Mesocorticolimbic Regions of Rats

“…It is important to note that handled rats single-housed for 14 days showed higher locomotor response to AMPH than did handled rats singlehoused for 3 days. The increased locomotor response to AMPH in drug-naive rats handled/stressed 14 days earlier is likely due to the longer period of single-housing, a form of social isolation which can elevate rewarding effects of psychostimulants (Deroche et al, 1994) and can amplify the physiological effect of social defeat (de Jong et al, 2005a). In the present study, handled/stressed rats received control virus, and non-viral-treated rats that were single-housed for 2 weeks showed similar locomotor responses to AMPH.…”

Adolescent social stress does not necessarily lead to a compromised adaptive capacity during adulthood: A study on the consequences of social stress in rats

“…The finding that social housing tended to facilitate instead of ameliorate the acute effects on body weight gain and changes in neuroplasticity markers like hippocampal cell proliferation and neurogenesis was rather unexpected. Previous studies in adult male rats exposed to social defeat followed by either isolation or social housing show a clear buffering effect of social housing on the stressinduced decrease on body weight gain (Koolhaas et al, 1997(Koolhaas et al, , 2011Martinez et al, 1998;Ruis et al, 1999;de Jong et al, 2005). In adult rats, the social buffering effect is stronger when the experimental animal is housed with an unstressed partner than with a stressed partner (Kiyokawa et al, 2004), and even short time exposure to a stressed conspecific has been shown to alter the behavior in adolescent rats un-exposed to stress themselves (Jacobson-Pick et al, 2011).…”

“…In adult males, these effects have been demonstrated to persist long after the original defeat experience when the experimental intruder animals are singly housed following the defeat (Meerlo et al, 1996;Buwalda et al, 1999). As for the beneficial aspect of the social environment such as social support during stress, adult laboratory rodents have been shown to respond positively to the presence of a non-hostile companion much like humans respond to the presence and support from a good friend during hardship (Ruis et al, 1999;Wilson, 2001;de Jong et al, 2005;Nakayasu and Ishii, 2008;Hennessy et al, 2009;Cherng et al, 2010;Macone et al, 2011). Hence, different social housing conditions during stress may serve as a useful rodent model for studying the buffering effect of social support.…”

“…As mentioned above, it is known that social defeat stress in adult rodents produces long-lasting effects on brain, physiology and behavior when these animals are singly housed after the defeat and that social housing ameliorates the negative consequences of the social stress (Ruis et al, 1999;de Jong et al, 2005). During development it is even more important that animals are allowed to have social interactions with their peers.…”

Social defeat, a paradigm of depression in rats that elicits 22-kHz vocalizations, preferentially activates the cholinergic signaling pathway in the periaqueductal gray

“…We have chosen to use another well standardized model, based on social submission in adult male rats [50,69], to identify the genetic consequences of social loss. The chronic stress that occurs in the presence of persistent loss in aggressive social encounters [2,57 especially in the absence of social support [69,18], is a major factor that sets in motion incompletely understood neurobiological events that leads to affective deficits and depressive disorders [49,57,58,66,81].…”