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Although pain reduction after alcohol administration has repeatedly been demonstrated, alcohol effects on advanced and clinically relevant dynamic pain paradigms are still unknown. As such, temporal summation of pain (TSP) and conditioned pain modulation (CPM) indicate mechanisms of endogenous pain modulation and involve certain neurotransmitter systems crucially influenced by alcohol. Our study is the first to investigate acute alcohol effects on TSP and CPM. We investigated 39 healthy subjects in a placebo-controlled within-subject design and targeted alcohol levels of 0.06% (dose 1) and 0.08% (dose 2). Pain threshold, TSP, and CPM were evaluated before and after an alcoholic or placebo drink. Temporal summation of pain was assessed as enhanced pain response to 5 repetitive contact heat stimuli (threshold +3°C). Conditioned pain modulation was tested as pain inhibition when a conditioning stimulus (46°C hot water) was applied concurrently to a test stimulus (contact heat; threshold + 3°C). Both alcohol doses boosted CPM, with a greater effect size for the higher dose. Conditioning stimulus ratings increased after alcohol intake but were not correlated with CPM, suggesting independence of these effects. Temporal summation of pain was not affected by alcohol, and alcohol effects on pain threshold were small and limited to the higher dose. Our findings suggest that analgesic alcohol effects might be mainly driven by an enhancement of endogenous pain inhibition. The frequent use of alcohol as self-medication in chronic pain might be motivated by alcohol temporarily restoring deficient CPM, thus leading to pain relief in the short run and alcohol-related problems in the long run.
Learn More >Prescription opioid misuse is a public health problem that leads to overdose. Although existing interventions focus on limiting prescribing to patients at high risk, individuals may still access prescription opioids dispensed to family members.
Learn More >Migraine is a chronic neurologic disease that can be associated with significant migraine-related impact, disability, and burden. Patient-reported outcome measures (PRO) are included in clinical trials of migraine interventions to capture treatment effects from a patient perspective. Clinical and regulatory guidelines also encourage use of PROs in trials. The Migraine Functional Impact Questionnaire (MFIQ) is a novel PRO measure, assessing the impact of migraine on Physical Function (PF), Usual Activities (UA), Social Function (SF), and Emotional Function (EF), in the past 7 days. Scientific methods recommended to meet the requirements of the U.S. Food and Drug Administration were followed, to ensure that the MFIQ content included outcomes that were relevant to adults with migraine and were clinically relevant, specifically to evaluate preventive treatments for migraine.
Learn More >Mitragyna speciosa (kratom) may hold promise as both an analgesic and treatment for opioid use disorder. Mitragynine, its primary alkaloid constituent, is an opioid receptor ligand. However, the extent to which the in vivo effects of mitragynine are mediated by opioid receptors, or whether mitragynine interacts with other opioid agonists, is not fully established.
Learn More >P2X4 is a ligand-gated ion channel implicated in neuropathic pain. Drug discovery efforts targeting P2X4 have been unsuccessful largely due to the difficulty in engineering specificity and selectivity. Here, we describe for the first time the generation of a panel of diverse monoclonal antibodies (mAbs) to human and mouse P2X4, capable of both positive and negative modulation of channel function. The affinity optimised anti-P2X4 mAb IgG#151-LO showed exquisite selectivity for human P2X4 and induced potent and complete block of P2X4 currents. Site-directed mutagenesis of P2X4 revealed the head domain as a key interaction site for inhibitory mAbs. Inhibition of spinal P2X4 either by intrathecal delivery of an anti-P2X4 mAb, or systemic delivery of an anti-P2X4 bi-specific mAb with enhanced blood-spinal cord barrier permeability, produced long lasting (>7 days) analgesia in a mouse model of neuropathic pain. We therefore propose that inhibitory mAbs binding the head domain of P2X4 have therapeutic potential for the treatment of neuropathic pain.
Learn More >In most mature neurons, low levels of intracellular Cl concentrations ([Cl]) are maintained by channels and transporters, particularly the K-Cl cotransporter 2 (KCC2), which is the only Cl extruder in most neurons. Recent studies have implicated KCC2 expression in the molecular mechanisms underlying neuronal disorders, such as spasticity, epilepsy and neuropathic pain. Alterations in KCC2 expression have been associated with brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin-related kinase B (TrkB). The present review summarizes recent progress regarding the roles of Cl regulators in immature and mature neurons. Moreover, we focus on the role of KCC2 regulation via the BDNF-TrkB pathway in spinal cord injury and rehabilitation, as prior studies have shown that the BDNF-TrkB pathway can affect both the pathological development and functional amelioration of spinal cord injuries. Evidence suggests that rehabilitation using active exercise and mechanical stimulation can attenuate spasticity and neuropathic pain in animal models, likely due to the upregulation of KCC2 expression via the BDNF-TrkB pathway. Moreover, research suggests that such rehabilitation efforts may recover KCC2 expression without the use of exogenous BDNF.
Learn More >To assess the effects of migraine on important life domains and compare differences between respondents with episodic and chronic migraine and between sexes.
Learn More >The current study aimed to identify alterations in brain activation and connectivity related to nociceptive processing and pain sensitization in major depressive disorder (MDD), using repetitive heat pain stimulation during functional magnetic resonance imaging (fMRI) in 37 MDD patients and 33 healthy controls. Regional activation did not differ between groups, but functional connectivity was significantly decreased in MDD in a neural network connecting frontal, temporal and occipital areas (family-wise error-corrected p = 0.045). Supporting analyses suggested a significant association between network connectivity and trait neuroticism (p = 0.007) but not with the clinical state or familiar risk of MDD (all p values > 0.13). Our data relate a network-based phenotype for altered pain processing and antinociceptive control to MDD and encourage future studies on the shared intermediate neural psychological risk architecture of MDD and chronic pain.
Learn More >Multimodal analgesia (MMA) is the simultaneous use of multiple analgesic medications that work in a synergistic manner to provide pain control. In recent years, spine surgery has seen the growth of multimodal perioperative protocols for managing pain. Postoperative pain following spinal procedures is a common complaint, with persistent pain even after the immediate convalescent period leading to negative impacts on health. A multidisciplinary approach is essential in reducing postoperative morbidity and complication rates. This review demonstrates the efficacy in the combined use of opioid-alternative medications such as NSAIDs, gabapentinoids, local anesthetics, acetaminophen, and other neuromodulatory pharmacologic agents. Continued research will be essential in the optimization of the MMA protocol for treating patients who undergo spine procedures.
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