Inhibition of Nitric Oxide Synthesis Prevents the Effects of Intermittent Social Defeat on Cocaine-Induced Conditioned Place Preference in Male Mice.

We have previously observed that exposed to social defeat stress are more sensitive to cocaine in the conditioned place preference (CPP) paradigm. In this context, it has been suggested that the nitric oxide (NO) pathway plays a role in the effects of stress. The present study evaluates the role of a neuronal NO synthase (nNOS) inhibitor (7-nitroindazole, 7-NI) in the short- and long-term behavioural effects of intermittent social defeat (ISD).

Behavioural traits related with resilience or vulnerability to the development of cocaine-induced conditioned place preference after exposure of female mice to vicarious social defeat.

Exposure to stress induced by intermittent repeated social defeat (IRSD) increases vulnerability to the development of cocaine-induced conditioned place preference (CPP) among male mice; however, some defeated mice are resilient to these effects of stress. In the present study we evaluated the effects of vicarious IRSD (VIRSD) in female mice and explored behavioural traits that are potentially predictive of resilience. C57BL/6 female mice (n = 28) were exposed to VIRSD, which consisted of the animals witnessing a short experience of social defeat by a male mouse on postnatal day (PND) 47, 50, 53 and 56.

Vicarious Social Defeat Increases Conditioned Rewarding Effects of Cocaine and Ethanol Intake in Female Mice.

Stress is a critical factor in the development of mood and drug use disorders. The social defeat model is not appropriate for female rodents due to their low level of aggression. Therefore, a robust female model of social stress needs to be developed and validated.

Social defeat in adolescent mice increases vulnerability to alcohol consumption.

This study employs an oral operant conditioning paradigm to evaluate the effects of repeated social defeat during adolescence on the reinforcing and motivational actions of ethanol in adult OF1 mice. Social interaction, emotional and cognitive behavioral aspects were also analyzed, and real-time polymerase chain reaction (PCR) experiments were performed to study gene expression changes in the mesocorticolimbic and hypothalamus-hypophysis-adrenal (HHA) axis. Social defeat did not alter anxiety-like behavior in the elevated plus maze or cognitive performance in the passive avoidance and Hebb-Williams tests.