Articles: opioid.
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Comparative Study
Endogenous opioids regulate glucocorticoid-dependent stress coping strategies in mice.
Coping skills are essential in determining the outcomes of aversive life events. Our research was aimed to elucidate the molecular underpinnings of different coping styles in two inbred mouse strains, C57BL/6J and SWR/J. We compared the influence of a preceding stressor (0.5h of restraint) on behavioral and gene expression profiles between these two strains. ⋯ We found that treatment with a glucocorticoid receptor (GR) agonist (dexamethasone (DEX), 4mg/kg) impaired the consolidation of fear memory in the C57BL/6J mice and that this effect was reversed by OR blockade (naltrexone (NTX), 2mg/kg). In parallel, a glucocorticoid receptor antagonist (mifepristone (MIF), 20mg/kg) reversed the effect of morphine (20mg/kg) on conditioned fear in the C57BL/6J mice. Our results suggest that in mice, stress-coping strategies are determined by opioid-dependent mechanisms that modulate activity of the HPA axis.
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Sleep fragmentation has been linked to poor pain tolerance and lowered pain threshold. Little evidence exists on whether continuous positive airway pressure (CPAP) adherence in veterans with obstructive sleep apnea (OSA) who are taking opioids for non-malignant pain would ameliorate pain and reduce consumption of opioids. ⋯ CPAP treatment did not reduce pain intensity or consumption of opioids in veterans with chronic pain who have coexisting OSA. CPAP adherence was lower in opioid-treated veterans with OSA compared to opioid-free veterans with OSA. Pain intensity was the only determinant of CPAP adherence. Future studies are needed to evaluate pain management program on adherence to CPAP.
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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.