Newswise — New research led by UCLA Health has found a drug that treats insomnia works to prevent the addictive effects of the morphine opioids in mice while still providing effective pain relief. The study , published in the journal Nature Mental Health , concluded that suvorexant, which blocks brain receptors for a neurotransmitter called hypocretin, prevents opioid addiction. At high doses in humans, suvorexant induces sleep and is used to treat insomnia.
But sleep was not induced, and behavioral alertness was maintained, at the much lower doses effective in preventing opioid addiction in mice. Hypocretin, also called orexin, is a peptide that is linked to mood, with hypocretin release in humans being maximal during pleasurable activities and minimal during pain or sadness. The loss of hypocretin neurons is the cause of narcolepsy, which is thought to be an autoimmune disease.
People with narcolepsy and mice made narcoleptic have a greatly diminished susceptibility to opiate addiction. Researchers have found both humans addicted to heroin and mice addicted to morphine develop higher numbers of hypocretin producing neurons. Morphine causes hypocretin neurons to increase their anatomical connections to pleasure related brain regions.
The latest study in mice found that administering opioids with suvorexant prevents opioid-induced changes in hypocretin neurons, prevents hypocretin neurons from increasing their connections to the brain’s reward related regions, greatly red.