Serotonin affects the part of the brain involved in drug reward and cue reactivity, particularly through the serotonin 2C receptors.
A recent study published in ACS Chemical Neuroscience reported that a prescription weight-loss drug reduced the urge to use opiates like oxycodone.1
Current treatments to reduce opiate misuse operate by occupying opioid receptors in the brain to lessen the “signature euphoria.” But due to cue reactivity, many who have tried available treatments often relapse when they are around the places, people, or objects they associate with opiate use.
Researchers from the University of Texas Medical Branch (UTMB) at Galveston found that lorcaserin, a serotonin 2C receptor agonist, decreased the craving for oxycodone in pre-clinical studies. Serotonin affects the part of the brain involved in drug reward and cue reactivity, particularly through the serotonin 2C receptors. Earlier research by Kathryn Cunningham, PhD, professor at UTMB, had shown how lorcaserin reduced the number of times rats completed a simple task to earn a dose of cocaine. But much less was known about the role of serotonin 2C receptors in altering how opiates feel for the user.
For this study, the researchers trained rats to self-administer oxycodone while exposed to certain lights and sounds that produced a drug-taking environment. After the rats were used to regularly taking oxycodone, they were no longer given it for a period of time. The rats were then given either lorcaserin or placebo and placed in the drug-associated environment. When oxycodone was made available again, the lorcaserin group self-administered less oxycodone and reacted less strongly to drug-associated cues.
Another group of rats were given lorcaserin as well as a serotonin 2C receptor blocker to demonstrate that this effect was due to lorcaserin. The study authors found these rats tried very hard to obtain oxycodone.
Dr Cunningham noted: “The effectiveness of lorcaserin in reducing oxycodone-seeking and craving highlights the therapeutic potential for lorcaserin in the treatment of opioid use disorder. We plan more studies to better understand how drugs like lorcaserin can help us stem the tide of addiction in America.”
- Neelakantan H, Holliday ED, Fox RG, et al. Lorcaserin suppresses oxycodone self-administration and relapse vulnerability in rats. ACS Chem Neurosci. 2017. doi: 10.1021/acschemneuro.6b00413