Skip to main content

Sex differences and drug abuse

By
Holly et. Al (2012) used an episodic social defeat stress paradigm to understand the differences between male and female rats as well as the effect of the female estrous cycle in behavioral and dopaminergic cross-sensitization to cocaine. The results indicate that episodically stressed females have significantly greater behavioral sensitization than controls as well as stressed male counterparts. This behavioral sensitization of increased locomotion activity in response to cocaine was also longer-lasting in the females, with higher levels seen in estrous females. There were no obvious group differences in neural sensitization, but the authors noted this limitation may be due to small sample size, and that more subjects might show statistically significant numbers. I’d be curious to see a follow-up study specifically built around the idea of stress exposure and circulating estradiol on dopaminergic function in females. In terms of its clinical usage and applications, I thought about how it’s known that women are more susceptible to craving and relapse, and if this has anything to do with estradiol/dopaminergic interactions. For example, if we compare this to the female menstrual cycle, is an adult female more likely to fall into a pattern of relapse after trying cocaine during a specific time of the cycle and furthermore, would she crave it more during a certain period of the cycle? Understanding this and the interaction it has could potentially see a future in developing more efficient treatment plans for substance use disorders.

Vassoler et al. (2013) presented robust epigenetic data illustrating how paternal cocaine self-administration causes an acetylation effect which literally reprograms the germline to inherit a neural and behavioral phenotype of reduced cocaine reinforcement. I thought this paper was really interesting, and especially enjoyed the data regarding a potential functional change in sperm that may be caused by cocaine. Similar to my comments regarding the Holly et al. paper, I’m intrigued by substance abuse studies on both a sex difference level and a developmental level (i.e. adolescent substance abuse problems and implementing treatments so patients don’t find themselves in patterns of relapse). We have ways to go in terms of understanding addiction and why it happens, but I’m excited to see how studies such as these might manifest into clinical applications for humans. Furthermore, I appreciate how female cohorts--which have been wrongfully neglected in the world of neuroscience--were heavily included (and the stars of the show in Holly et al.) in both these studies. 

Comments

Post a Comment

Popular posts from this blog

Week 2- Dopamine Modulation of Depressive-like Behaviors

By
The Chaudhury et al paper explored the neural circuit mechanisms involved in the dopamine modulation of certain symptoms of depression. In this study, the researchers looked at social interaction and sucrose preference as part of their social-defeat paradigm, which has been shown in the past to be indicative of depressive-like behaviors. Although I initially did not completely see the connection between the social-defeat stress model of depression and the tonic vs phasic firing of dopamine neurons, it seemed that susceptibility and resilience to stress played a role in the functional/behavioral effects of dopamine firing. It was interesting to see how chronic mild stress with phasic firing of VTA dopamine neurons converted even resilient mice into susceptible mice.  The Tye et al paper similarly looked at the dopamine modulation of depressive-like behaviors, focusing on motivation with the forced swim tests and open field tests, followed by measurement of anhedonia by quantifyi...
Post a Comment
Read more

Sial & Allsop

By
Sial et al. derived a novel approach for studying what they deem vicarious defeat stress (VSDS) as a model for MDD, PTSD, and other mood-related disorders as an alternative to the classical CSDS paradigm. Using adult male mice, they demonstrate that their model induces a robust and measurable social avoidant phenotype as well as other stress and anxiety related behavioral outputs. Their subsequent rescue study with chronic fluoxetine treatment shows reversal of the behavioral phenotypes and emphasizes the predictive validity of the model. Allsop et al. found that BLA-projecting ACC neurons preferentially encode socially derived aversive cue information by encoding the demonstrator’s distress response during observational learning, hence enabling acquisition of negative valence of cue by BLA neurons and behavioral output. In order to test their hypothesis, Allsop et al. used an observational fear conditional paradigm to create association between a conditioned stimulu...
Post a Comment
Read more

Buffington and Reber

By
Buffington et al. explore a mechanism by which maternal obesity can induce neuronal and subsequent behavioral disorders. Using a model of high-fat diet (MHFD)-induced obesity, the authors showcase the strong connection between the brain and the gut, and its impact on behavior. The findings are provocative; by exposing these offspring to the microbiome of control offspring, there was evidence of a rescued observed behavioral phenotype. Furthermore, a phylogenetic profiling of the gut microbiome revealed a decrease in L. reuteri within MHFD offspring, and introduction of live L. reuteri into the drinking water shows successful rescue of the behavioral issues in the MHFD offspring. L. reuteri-induced expression of oxytocin within the paraventricular nuclei of the hypothalamus provides a potential mechanistic explanation for the behavioral changes. I thought this paper provided robust support for the hypothesized interaction between the gut biome and the developing CNS, with tremendous po...
Post a Comment
Read more