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IntroductionThe periaqueductal gray (PAG) mediates the antinociceptive properties of analgesics, including opioids and cannabinoids. Administration of either opioids or cannabinoids into the PAG induces antinociception. However, most studies characterizing the antinociceptive properties of cannabinoids in the PAG have been conducted in naive animals. Few studies have reported on the role of CB1 receptors in the PAG during conditions which would prompt the administration of analgesics, namely, during pain states.ObjectivesTo examine inflammatory pain-induced changes in CB1 receptor expression and function in the midbrain periaqueductal gray.MethodsIn this study, we used the Complete Freund Adjuvant model to characterize CB1 receptor expression and G-protein coupling during persistent inflammatory pain.ResultsInflammatory pain induced an upregulation in the expression of synaptic CB1 receptors in the PAG. Despite this pain-induced change in CB1 expression, there was no corresponding upregulation of CB1 mRNA after the induction of inflammatory pain, suggesting a pain-induced recruitment of CB1 receptors to the synaptic sites within PAG neurons or increased coupling efficiency between the receptor and effector systems. Inflammatory pain also enhanced ventrolateral PAG CB1 receptor activity, as there was an increase in CP55,940-stimulated G-protein activation compared with pain-naïve control animals.ConclusionThese findings complement a growing body of evidence which demonstrate pain-induced changes in brain regions that are responsible for both the analgesic and rewarding properties of analgesic pharmacotherapies. Because much of our understanding of the pharmacology of cannabinoids is based on studies which use largely pain-naïve male animals, this work fills in important gaps in the knowledge base by incorporating pain-induced adaptations and cannabinoid pharmacology in females.

Negative affective states affect quality of life for patients suffering from pain. These maladaptive emotional states can lead to involuntary opioid overdose and many neuropsychiatric comorbidities. Uncovering the mechanisms responsible for pain-induced negative affect is critical in addressing these comorbid outcomes. The nucleus accumbens (NAc) shell, which integrates the aversive and rewarding valence of stimuli, exhibits plastic adaptations in the presence of pain. In discrete regions of the NAc, activation of the kappa opioid receptor (KOR) decreases the reinforcing properties of rewards and induces aversive behaviors. Using complementary techniques, we report that in vivo recruitment of NAc shell dynorphin neurons, acting through KOR, is necessary and sufficient to drive pain-induced negative affect. Taken together, our results provide evidence that pain-induced adaptations in the kappa opioid system within the NAc shell represent a functional target for therapeutic intervention that could circumvent pain-induced affective disorders. VIDEO ABSTRACT.

Background: Voter initiatives in Oregon and Colorado authorize legal frameworks for supervised psilocybin services, but no measures monitor safety or outcomes. Aims: To develop core measures of best practices. Methods: A three-phase e-Delphi process recruited 36 experts with 5 or more years' experience facilitating psilocybin experiences in various contexts (e.g., ceremonial settings, indigenous practices, clinical trials), or other pertinent psilocybin expertise. Phase I, an on-line survey with qualitative, open-ended text responses, generated potential measures to assess processes, outcomes, and structure reflecting high quality psilocybin services. In Phase II, experts used seven-point Likert scales to rate the importance and feasibility of the Phase I measures. Measures were priority ranked. Qualitative interviews and analysis in Phase III refined top-rated measures. Results: Experts (n = 36; 53% female; 71% white; 56% heterosexual) reported currently providing psilocybin services (64%) for a mean of 15.2 [SD 13.1] years, experience with indigenous psychedelic practices (67%), and/or conducting clinical trials (36%). Thematic analysis of Phase I responses yielded 55 candidate process measures (e.g., preparatory hours with client, total dose of psilocybin administered, documentation of touch/sexual boundaries), outcome measures (e.g., adverse events, well-being, anxiety/depression symptoms), and structure measures (e.g., facilitator training in trauma informed care, referral capacity for medical/psychiatric issues). In Phase II and III, experts prioritized a core set of 11 process, 11 outcome, and 17 structure measures that balanced importance and feasibility. Conclusion: Service providers and policy makers should consider standardizing core measures developed in this study to monitor the safety, quality, and outcomes of community-based psilocybin services. [ABSTRACT FROM AUTHOR]

The article argues for safety monitoring systems and regulation of services when expanding access to psychedelics to reduce harm, with reference to a study which characterized lysergic acid diethyl acid dietylamide and psilocybin-related deaths in Australia. It urges for better systems for assessing population risks in regulated and unregulated settings, tracking of adverse effects and benefits, and enrollment of people who use psychedelics in secure data collection systems.

In 2014, drug overdose surpassed automobile accidents as the number one cause of accidental death for the first time in the history of the United States. The overdose epidemic is largely driven by opioids, and genuine prescription opioid analgesics play the biggest role in this phenomenon. Despite advancements in abuse deterrent formulations, prescription drug monitoring programmes and clinical assessments for the detection of abuse potential, drug overdoses continue to escalate. The Center for Disease Control has recently issued new guidelines for opioid prescription, yet even these recommendations have their shortcomings. Furthermore, undertreated pain in patients with comorbid substance use disorder poses a major clinical challenge, particularly for patients on opioid replacement therapy. Despite the seemingly obvious interaction between the presence of pain and the abuse of pain-relieving opioids, there is surprisingly little mechanistic data to further our understanding of this vitally important topic. The need for novel pain interventions that minimize abuse liability is critical. Without a fundamental characterization of pain neurobiology and the interaction between chronic pain and the brain's reward system, we are unlikely to make progress in the alleviation of the opioid epidemic.Linked Articles: This article is part of a themed section on Emerging Areas of Opioid Pharmacology. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.14/issuetoc. [ABSTRACT FROM AUTHOR]

The opioid epidemic has become an immense problem in North America, and despite decades of research on the most effective means to treat opioid use disorder (OUD), overdose deaths are at an all-time high, and relapse remains pervasive. Although there are a number of FDA-approved opioid replacement therapies and maintenance medications to help ease the severity of opioid withdrawal symptoms and aid in relapse prevention, these medications are not risk free nor are they successful for all patients. Furthermore, there are legal and logistical bottlenecks to obtaining traditional opioid replacement therapies such as methadone or buprenorphine, and the demand for these services far outweighs the supply and access. To fill the gap between efficacious OUD treatments and the widespread prevalence of misuse, relapse, and overdose, the development of novel, alternative, or adjunct OUD treatment therapies is highly warranted. [ABSTRACT FROM AUTHOR]