Articles: opioid.
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Journal of anesthesia · Aug 2016
Effect of interleukin 6 -174G>C gene polymorphism on opioid requirements after total hip replacement.
In recent years, increasing attention has been paid to the contribution of genetic factors to variability in patient pain threshold and the efficacy of pain management. One of the genes implicated in pain pathology and treatment response is interleukin 6 (IL6). The aim of the present study was to evaluate the association between IL6 (rs1800795: -174G>C) and opioid requirements in patients after total hip replacement (THR). ⋯ The presence of the G allele IL6 gene (-174G>C) polymorphism was found to be an independent factor predisposing to a higher dose and more frequent administration of opioids in the first days after total hip replacement.
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Am. J. Physiol. Gastrointest. Liver Physiol. · Aug 2016
Distribution and trafficking of the μ-opioid receptor in enteric neurons of the guinea pig.
The μ-opioid receptor (MOR) is a major regulator of gastrointestinal motility and secretion and mediates opiate-induced bowel dysfunction. Although MOR is of physiological and therapeutic importance to gut function, the cellular and subcellular distribution and regulation of MOR within the enteric nervous system are largely undefined. Herein, we defined the neurochemical coding of MOR-expressing neurons in the guinea pig gut and examined the effects of opioids on MOR trafficking and regulation. ⋯ After stimulation with DAMGO and morphiceptin, MOR recycled, whereas MOR was retained within endosomes following loperamide treatment. Herkinorin or the δ-opioid receptor agonist [d-Ala(2), d-Leu(5)]enkephalin (DADLE) did not evoke MOR endocytosis. In summary, we have identified the neurochemical coding of MOR-positive enteric neurons and have demonstrated differential trafficking of MOR in these neurons in response to established and putative MOR agonists.
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Opioid therapy for pain is associated with an increased risk for substance use disorders. This study's purpose was to determine the association between opioid misuse propensity (Screener and Opioid Assessment for Patients in Pain-Revised) and delay discounting (DD), a behavioral process linked to substance use disorders, which quantifies the extent to which outcomes are devalued because of their delay. Participants reporting chronic pain (N = 249) answered pain and opioid use questions and then completed 4 DD tasks. ⋯ Similarly, the novel Additional Pain Choice Questionnaire assessed choices between an immediate short duration of additional pain vs a longer duration of additional pain. Discounting of both additional pain and money losses were significantly associated with high Screener and Opioid Assessment for Patients in Pain-Revised scores-indicating participants at greatest risk for opioid misuse discount future punishments rather than future rewards compared with those at low risk. Measures of DD may have promise in more accurately identifying individuals at highest risk for opioid misuse during chronic opioid therapy.
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Expert Opin. Ther. Targets · Aug 2016
ReviewNav1.7 and other voltage-gated sodium channels as drug targets for pain relief.
Chronic pain is a massive clinical problem. We discuss the potential of subtype selective sodium channel blockers that may provide analgesia with limited side effects. ⋯ We believe there is a great future for sodium channel antagonists, particularly Nav1.7 antagonists in treating most pain syndromes. This review deals with recent attempts to develop specific sodium channel blockers, the mechanisms that underpin the Nav1.7 null pain-free phenotype and new routes to analgesia using, for example, gene therapy or combination therapy with subtype specific sodium channel blockers and opioids. The use of selective Nav1.7 antagonists together with either enkephalinase inhibitors or low dose opioids has the potential for side effect-free analgesia, as well as an important opioid sparing function that may be clinically very significant.
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Randomized Controlled Trial
One Month of Oral Morphine Decreases Gray Matter Volume in the Right Amygdala of Individuals with Low Back Pain: Confirmation of Previously Reported Magnetic Resonance Imaging Results.
Prolonged exposure to opioids is known to produce neuroplastic changes in animals; however, few studies have investigated the effects of short-term prescription opioid use in humans. A previous study from our laboratory demonstrated a dosage-correlated volumetric decrease in the right amygdala of participants administered oral morphine daily for 1 month. The purpose of this current study was to replicate and extend the initial findings. ⋯ Many of the volumetric increases and decreases overlapped spatially with the previously reported changes. Individuals taking placebo for 1 month showed neither gray matter increases nor decreases. The results corroborate previous reports that rapid alterations occur in reward-related networks following short-term prescription opioid use.