Holly et al., 2012

I really enjoyed this article, mainly because I appreciated that it looked at sex differences. Additionally, I liked that it even looked at the differential effects of stress on both estrous and non-estrous female rodents. I did have a few questions/issues with this paper though. First of all, I am interested in why they chose to use a social defeat stress paradigm. I know that this paradigm has been shown to be related to cross-sensitization to cocaine; however, I have a hard time relating this to humans. I think that it would be interesting to do this study again, using a different type of stress (such as chronic mild stress) and see how the results differ. Since many drug users come from a low SES population and have had stressful early life experiences, it seems as if chronic mild stress may be more relevant to many of cocaine users than social defeat stress. Additionally, I am curious as to how the experimenters got the female rats to be so aggressive. I thought that the reason why most papers don’t use social defeat with female rodents is because they typically are not aggressive and don’t fight unless they are pregnant or nursing. However, this paper states that the latency to aggression was the same in both males and females. Another question that I have is, have there been observed differences in the effect of stress in humans during different times during the menstrual cycle? I thought it was really interesting that the estrous cycle affects locomotion but not the binge in self-administration of cocaine. I really enjoyed learning about the sex differences in this paper, and I really wish that more papers would focus on sex differences since it is clear that males and females respond very differently to similar stimuli.