Sex Differences in Cocaine Administration

I found it unsurprising that female rats would have dopaminergic tone mediated by the presence of estradiol, and that this was not the case for castrated males. Recent studies show that females have a harder time dealing with chronic stress. This goes in line with the idea that the neuro-endocrine and neurobehavioral changes associated with female rats take place on a longer time scale. This explains the sustained dopamine elevation after stress since this might be a compensatory mechanism to prevent the negative symptoms of long lasting and chronic stress. This model might make sense from an evolutionary perspective. Males, having aggressive phenotypes and presence of testosterone, may be unlikely to feel chronic stress since they have a means of protecting themselves, while females do not. Thus males encounter acute stress and as such their baseline dopamine elevation after stress and cocaine administration spike for shorter duration but with great intensity.

Comments

Post a Comment

Popular posts from this blog

Microbiotic effects on stress and social behavior in mice- Sierra Smith

For the final week of paper discussions, we dove into the fascinating and very new topic of the gut microbiome, and the influence of microbiotic composition on mice either under chronic subordinate colony housing situations or the offspring of dames fed a high-fat diet. In the first paper I read, Reber et al, there were fascinating findings that although supplementation with heat-killed Mycobacterium vaccae did not prevent all microbiotic changes induced by stressful housing conditions, it did have a significantly protective effect on the development of spontaneous colitis and stress-induced aggravation of pre-existing inflammatory bowel disease (colitis in mice). There was also a profound effect on proactive defensive behaviors in mice housed in CSC conditions, whereas they became defeated less easily and displayed significantly more proactive behaviors when faced with an aggressor. I was particularly excited to read about the increased Iba1 immunostaining in fear-regulato...
Read more

ACC-BLA Connections and Observational Learning- Annissa DeSilva

            Observational fear learning is an innate social behavior, Allsop et al. 2018 outlines the neural circuit underlying how the brain encodes emotionally salient (fear) behavior with neutral cues associated through observational fear learning. Allsop et al, found that projections from the Anterior cingulate cortex (ACC) to the Basolateral Amygdala (BLA) are essential in encoding observational learning. Specifically observing distress causes basal changes in the ACC neurons (encoding of the observed behavior through social cues) which enables the acquisition of the predictive nature of the aversive cue by BLA neurons. When ACC - BLA projections were optogenetically inhibited while mice were observing fear conditioning a reduced freezing response was seen when conditioned fear response was tested. Interestingly when the ACC - BLA projections were inhibited during testing of observational fear conditioning the...
Read more

Two sides of the same coin?: the bidirectional effects of VTA-NAc DA neurons - Emily Jones

Papers like the ones assigned this week reminded of the reasons I opted to take this class. Research into the biological nuances of complex clinical disorders really reinforces the idea that everything psychological is simultaneously biological. And in these papers, optogenetics amazingly gives us a fast and efficient way to explore these nuances. Interestingly, both papers demonstrated a bidirectional effect of dopamine neurons in the VTA-NAc pathway on depression phenotypes using phasic photoactivation. However, it seemed that these effects were flipped. In other words, when Chaudhury et al. inhibited the neurons, a resilient phenotype was induced in previously susceptible mice (indicated by a high preference for sugar water and decreased social avoidance compared to control mice); when Tye et. al. use the same opsin to inhibit the same kind of neurons, depression phenotypes were induced. Indeed the differences may be due in large part to the different stress conditions the mice we...
Read more