Systemic infusions of amylin attenuate oxycodone-taking behavior in rats

Michelle using pipette

Students

2020
Nursing

Faculty

Associate Professor of Nursing and Psychiatry

Project Summary

Widely known for their analgesic effects, opioids are a class of drugs commonly prescribed to treat mild to severe pain. However, it has become very clear that their pain-relieving effects are accompanied by the high risk of addiction and dependence. Prescription opioid addiction is currently a major issue affecting countless lives in the U.S. In 2017, more than 4% of the U.S adult population (>10 million Americans) reported misusing prescription opioid analgesics. Of the 63,632 overdose deaths in 2016, it is estimated that 66.4% were opioid related.

So what exactly makes these drugs so addictive? A large part of it can be attributed to the dense number of opioid receptors found within two areas of the brain, known as the nucleus accumbens (NA) and ventral tegmental area (VTA). These two brain regions also make up part of what is known as the “mesolimbic reward system”, which is a pathway responsible for the craving of natural rewards such as food, water, and sex. Activation of the mesolimbic reward system releases dopamine, a neurotransmitter, which ultimately leads to the reinforcement of reward-seeking behaviors. By binding to their receptors, opioids are essentially triggering this reward pathway, inducing elevated levels of dopamine as well as the dangerous potential for addictive behavior.

To tackle the issue of prescription opioid dependence, our experiment investigated whether systemic infusions of amylin, a neuropeptide, could attenuate oxycodone-taking behavior. Amylin was specifically chosen due to current findings suggesting its ability to decrease food-intake, a type of natural reward. Our results demonstrate that systemic infusions of amylin do in fact decrease oxycodone-taking behavior, which provides the exciting possibility of the development of pharmacotherapies specific for opioid addiction.

In terms of my personal experience working in the lab, there is so much to share. However, perhaps the two most valuable lessons I have learned are that, firstly, research is as much about being organized, planning ahead, thinking critically, communicating effectively, and being careful when working with very, very expensive equipment as it is about “science”. In other words, there is so much more that goes into research than just “being smart” or scientific knowledge itself. Furthermore, while the term, “research”, may conjure images of pretty graphs and highly-esteemed journals in the minds of many, this summer has taught me that science can actually be pretty unglamorous at times. Yet, as much as I enjoyed learning those skills that fit my initial perception of “research”, such as performing rat catheter surgeries, intraperitoneal injections, slicing brains… looking back I think it was those seemingly “unglamorous” moments of cleaning cages, monitoring food readings, and sweeping the behavioral space that encouraged me to take a step back and really see what I was doing. To think that I could and was contributing to something that could potentially improve the lives of those affected by this opioid epidemic was truly humbling. However, none of this would have been possible without the support of my friends and mentors in the lab and I am truly grateful for having been granted this opportunity.