I’ve been interested in sex differences in research ever since being in Professor Shansky’s lab and learning about the huge impact of the estrous cycle on PTSD in female rats. After that experience, I couldn’t believe that the norm in research was to apply results from all-male animal experiments to all humans. In Holly et. al, I was surprised to see that females expressed a greater behavioral sensitization than males at all stages of their estrous cycles. I expected rats in estrus to be the only ones displaying this difference, with rats in non-estrus phases exhibiting the same behavioral sensitization as males. If I remember correctly from my days in the lab, it seems that fluctuating estrogen levels (depending on which phase of the estrous cycle the rat is in) somehow modulated dopamine levels, and I wonder if the same thing is going on here. I wish they gave more data specific to each part of the estrous cycle- not just in the locomotion task. I think there would be some interesting and possibly significant differences to observe. I was also confused about why they had the rats on a reverse light-dark cycle, and I wonder if this had any significance or purpose.
In general, I found the findings of the Vassoler et. al paper pretty fascinating. I did not expect at all for the male offspring of the cocaine-addicted fathers to actually have a delayed acquisition of cocaine self-administration. This suggests that having a cocaine-addicted father actually has protective benefits for male offspring, which really contradicts the notion that drug addiction is inheritable. Their observation of increased BDNF mRNA and protein levels in the mPFC of male offspring served as a good explanation for what they were observing, but it left me wondering why this same increase was not observed in female offspring. I would be really interested in seeing this experiment done with a much larger sample size, and with the father rats put into groups that are exposed to different levels of cocaine throughout the 60 days. I wonder if researchers would see a point where there is a shift, i.e up to a certain amount of paternal exposure to cocaine administration is protective (such as in this paper), but any amount past that is actually detrimental.