Study reveals neural mechanisms of opioid analgesia

On June 10,, the journal eLife published an online paper entitled "Exogenous and endogenous opioids act on the analgesic effects of inflammatory pain in different neuronal groups", completed by sun Yangang Research Group of the Center for Excellence in Brain Science and Intelligent Technology (Neuroscience Institute), Shanghai Brain Science and Brain Research Center, and National Key Laboratory of NeuroscienceCombined with technical techniques such asgeneticmanipulation, pharmacological experiments, fiber optic calcium recording, behavioral experiments, the study revealed that exogenous and endogenous opioids play an analgesic role in inflammatory pain, respectively, by acting on the expression of mu-type opioid receptors (MOR) in glutamate energy and gabacanic acid (GABA) energy neuronsThis study provides a new way of thinking for analyzing the function of opioid system and in-depth study of the pain control looppain is a complex feeling, normal pain feeling as a protective mechanism, is very important for the survival of animals and people, but the body's serious injury or chronic pain caused by chronic diseases seriously affect the quality of life of patientsPersistent or recurrent pain is one of the current clinical treatment challenges that plague more than 20% of the global populationTherefore, it is necessary to find a suitable and effective method of analgesicAmong the many pain treatments, opioids have been used in analgesia as early as thousands of years and have become the most clinically used and effective class of analgesics, but long-term use of opioids is limited by many serious side effectsAt present, the neural mechanism of opioid analgesia is not completely clear, so it is necessary to study the analgesia mechanism of opioids in depth for the development of new drugs with fewer side effectsexogenous and endogenous opioids play an analgesic role through mu receptor receptor, MOR, which acts extensively in the nervous systemIn order to analyze the mechanism of action of exogenous and endogenous opioids, the researchers used an experimental strategy of "knocking out first and restoring MOR expression in place" to study the function of MOR in the analgesic analgesic action of different types of neuronsThe study found that exogenous opioids ,such as morphine) produced ananalgesic effect seigniortic effects by ACTing on MOR in glutamate excitatory neurons, while endogenous opioids released in the body were able to relieve chronic inflammatory pain by acting on gamma-aminobutyric acid, GABA in the neuronsThe researchers further clarified the function of THE EXPRESSION IN ANalgesia, the spinal cord, and the level of the spinal cord in analgesicsAt spinal cord level, MOR is expressed in the back-corner neurons of the spinal cord with the main medial-mediated analgesic effect in acute pain, but is not involved in endogenous opioid analgesicsIn addition, MOR in spinal excitatory neurons and inhibitory neurons have the opposite function in the pain regulation process, activating MOR in the excitatory neurons of the spinal cord causes analgesic effect, while activating MOR in the spinal cord inhibitory neurons causes pain sensitivity The researchers also found that MOR, which is expressed at the spinal cord, was involved in the analgesic effect of morphine in inflammatory pain The study shows that endogenous and exogenous opioids play an analgesic role through different targets The study, published online in Neuroscience Bulletin in May 2020, revealed the role of MOR in opioid analgesics and opioid dependence in different types of neurons, providing an important basis for in-depth elaboration of the mechanisms of opioid action and improved use of opioids (
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