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Behavioral Sex Differences, Holly & Vassoler

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Studying sex differences in response to the same stimuli is a particularly interesting topic to me. In the case of the Holly and Vassoler papers, the stimulus is cocaine. Holly et al report that cocaine binges in response to social defeat stress causes female rats to "binge" cocaine significantly more than stressed males. Also, they reported that stressed females, but not males, saw a prolonged increase of extracellular dopamine in the Nucleus Accumbens. Vassoler et al report that ingesting cocaine can have trans-generational effects on the behavior of male cocaine-users' offspring, but not female. 

 Teasing apart the differences between the effects of cocaine in males and females is challenging. I think the most important thing that we can take away from the Holly and Vassoler papers is that cocaine certainly has differential effects on both sexes, both directly and trans-generationally. However, to what degree those effects are seen can vary widely depending on the organism and its environment. Are effects only seen in male offspring because the gene for "cocaine resistance" is on the Y-chromosome? The Vassoler paper mentions that progesterone has an opposing role to the effects of cocaine; could exogenous progesterone infusions prevent epigenetic changes in offspring? Further, could inhibiting progesterone in female rats who are given cocaine cause similar effects in their offspring as what's seen in the CocSired male offspring? 

 Both papers show great insight into what effects cocaine have at a molecular level in the brain. Ideally, I would like to see one big study combining the methods of both papers with large cohorts of animals to see the results of every possible combination, such as the trans-generational effects of cocaine addiction under stressful conditions and the levels of dopamine in CocSired offspring. Overall, I really enjoyed reading these papers and look forward to discussing them further. 

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