New research has discovered that a medication used to treat insomnia could help prevent the addictive properties of morphine opioids in mice without compromising pain relief.
A recent study conducted by UCLA Health revealed that a medication that typically treats insomnia could potentially deter the addictive effects of morphine opioids in mice while still maintaining pain-relieving benefits.
The study, which was published in the journal Nature Mental Health, found that suvorexant, a drug that blocks certain brain receptors for a neurotransmitter known as hypocretin, could effectively prevent opioid addiction. In humans, high doses of suvorexant induce sleep and are used for insomnia treatment. However, in mice, even much lower doses of suvorexant were able to prevent opioid addiction without inducing sleep, while still keeping the animals behaviorally alert.
Hypocretin, also referred to as orexin, is a peptide associated with mood regulation. In humans, hypocretin levels peak during pleasurable activities and decrease during times of pain or sadness. The deficiency of hypocretin neurons is linked to narcolepsy, believed to be an autoimmune disorder. People with narcolepsy, as well as narcoleptic mice, exhibit a reduced susceptibility to opiate addiction.
Studies indicate that both humans addicted to heroin and mice addicted to morphine demonstrate an increase in hypocretin-producing neurons. Morphine specifically triggers these neurons to establish more connections with brain regions associated with pleasure.
The latest research on mice revealed that administering opioids alongside suvorexant can counteract opioid-induced alterations in hypocretin neurons. This combined treatment prevents an increase in connections between hypocretin neurons and reward-related brain areas, significantly reduces opioid-induced brain inflammation, and curbs addictive behaviors, like mice running in anticipation of receiving their morphine dose. The study also showed that suvorexant, when given with morphine, significantly reduces withdrawal symptoms caused by morphine.
Dr. Jerome Siegel, the senior author of the study from UCLA Health, raised concerns about the increasing annual rate of opioid-related deaths in the US surpassing 80,000, exceeding the rates of deaths due to automobiles or firearms. While non-opioid pain relievers can manage mild pain effectively, they may fall short in treating severe pain resulting from conditions like burns, cancer, joint inflammation, sickle cell disease, and bone damage.
Siegel emphasized the need for further research to determine if the promising effects of suvorexant in suppressing addiction observed in mice can be replicated in humans using opioids for pain management. This potential could lead to safer and more efficient pain treatment without the risk of addiction and opioid overdose fatalities.
The study conducted involved 170 mice that received morphine over 14-day periods, examined postmortem brains of five individuals with opiate use disorder, and analyzed five control human brains. Further trials are essential to assess suvorexant’s efficacy in reducing addiction in humans using opioids for pain relief, as emphasized by Siegel.
