Skip to main content

Guglielmo and Venniro

By
This week's article continued are topic of addiction, looking at alcohol dependance in rats. In 2019 Guglielmo wt al. published a study investigating the relationship of corticotropin releasing hormone (CRH) cells in the central amygdala on withdrawal and alcohol dependence. They were able to show that the inactivation of a CRH-dependent amygdolofugal pathway with optoginetics was able to reverse addiction-like behaviors in rats dependent on alcohol. This area was selected as a target because of the relationship with somatic withdrawal symptoms. The CRH cells make up about 80% of the central amygdala with is the area most implicated in withdrawal symptoms following alcohol abuse in rats. This study was able to show that by blocking this pathway, male rats who choose to abstain from alcohol use when given access to self administration. While this changed alcohol intake, it did not affect normal behaviors such as water intake, implying that the rats are still healthy minded and able to attend to their needs and cravings. It did not surprise be that the HPA axis, and specifically CRH were involved in the withdrawal system after alcohol use. From what I learned in psychopharmacology is our bodies try to compensate from the depressant effects of alcohol and we end up rebounding the other direction. This release of hormones can cause stress and anxiety in attempt to counteract the dampened effect on our nervous system. What did surprise me is that many of the withdrawal symptoms were not reverses dipole a reversal of the behavior. As reported in the article 3/5 somatic withdrawal symptoms persisted after the optoginetic paradigm. This implies that the behaviors are separate from the withdrawal symptoms however their target is the same. In future research I would be curious to test this same area with other drugs. Would the same circuit improve drugs seeking behaviors r=for opioids or amphetamines? Would it only work for drugs thats act as depressants like benzodiazepines? In addition I agree with the research group that further studies must be conducted in females rats. As we have seen in so many previous studies as well as last weeks pice on addiction, the female brain functions differently and may not be affected by the same treatment.
In 2018, Venire et al. published a study looking at the relationship between volitional social interactions and drug addition. Their studied looked at both male and females rats and found that rats addicted to either methamphetamine or heroin would choose social interaction over drug self-administration. I was immediately happy to see the use of both sexes in this study. This study actually highlighted many similarities across both sexes which seemed to be unique compares to the stark differences we saw in last weeks articles. They found that both sexes largely preferred social interaction over both methamphetamine and heroin. What I found to be the most exciting conclusion from this article is the indication of a successful non-invasive, and non-pharmacological treatment for a disease. It is a rare thing in medicine to be able to treat a condition without a procedure or medication, but knowing their is hope in treating addiction with available and non-invasive treatment options is very inspiring to me as a future physician. The idea of using positive social interactions to treat a mental illness is very inspiring.

Comments

Post a Comment

Popular posts from this blog

Gut-Brain Interactions: Buffington et al, Reber et al 2016

By
April 13 Papers (Buffington et. al, Reber et. al) I found this week’s papers to be quite novel in that they both proposed potential treatments for neurodevelopmental or psychiatric disorders that target bacterial or microbial abnormalities and how these give rise to certain behavioral and physical symptoms associated with the disorders. I thought this was a very unusual yet interesting approach, and as I have not previously studied the gut-brain axis, these papers offered me a fresh perspective on researching psychiatric and neurodevelopmental disorders. They were also unconventional in their focus of the physical symptoms that often accompany mental disorders, as this is not something that I have seen many other papers touch upon very much. Particularly, I was surprised by the Reber et al paper’s focus on the link between psychiatric disorders and inflammation in organs other than the brain, such as the colon, and the Buffington et al paper’s description of a relationship between ...
Post a Comment
Read more

Gut-brain axis

By
This weeks papers Reber et al. 2016 and Buffington et al. 2016 present a super interesting look into the gut-brain axis. Regarding both of these papers, it was amazing to see how potent favorable or unfavorable gut microbiome compositions are in affecting neuronal signaling and overall behavior. Reber et al. shows how immunoregulatory immunization with specifically heat killed M.vaccae can serve as a protective factor against chronic subordinate stress induce colotis as well as behavioral symptoms due to chronic stress as such. Interestringly, this paper depleted regulatory T cell activity via the anti CD25 antibody in order to show that the antiinflammatory mechanism induced by m vaccae immunization is depented on the secondary regulatory mechanisms offered by Treg proliferation and signaling. But, when T reg signaling was removed, this did not seem to cause a significant change in behavior . Therefore, this begs the consideration of what othe rmechanisms may be at play in order ...
Post a Comment
Read more

Ramirez et al.: 2013 and 2015 Papers

By
In these papers, Ramirez et al. strive to understand how memory encoding via optogenetic manipulation of engram-bearing cells in the hippocampus, specifically the dentate gyrus, can affect an animal’s response to a stressful context.  The first paper, published in 2013, was crucial to the field as it introduced this very exciting technique; in this paper, Ramirez et al. use tet-tag to manipulate brain circuity and establish associations between two contexts. Throughout the paper, this is referred to as “false memories.” Using these artificial memories, the investigators are able to manipulate the animal’s fear response in a specific context. Specifically, after the animals are conditioned to a repeated fearful stimulus (a foot shock, in context B), activation of the involved DG cells in a different context (context A’) will also initiate a fear response (in absence of any foot shock). In this experiment, the false memory is used to create an unnatural fear association in a given...
Post a Comment
Read more