The journal of pain : official journal of the American Pain Society
-
Antimicrotubulin chemotherapeutic agents such as vincristine (VCR), often induce peripheral neuropathic pain. It is usually permanent and seriously harmful to cancer patients' quality of life and can result in the hampering of clinical treatments. Currently, there is no definitive therapy, and many of the drugs approved for the treatment of other neuropathic pain have shown little or no analgesic effect. ⋯ This synergistic interaction between DEX and UTI may be partly attributed to a common analgesic pathway in which the upregulation of interleukin -10 plays an important role via activating α2-adrenergic receptor in rat dorsal root ganglion. The combined use of DEX and UTI does not affect the rat's blood pressure, heart rate, sedation, motor score, spatial learning, or memory function. All of these show that the combined use of DEX and UTI is an effective method in relieving VCR-induced neuropathic pain in rats.
-
Neonatal injury is associated with persistent changes in sensory function and altered nociceptive thresholds that give rise to aberrant pain sensitivity in later life. Although these changes are well documented in adult rodents, little is known about the consequences of neonatal injury during adolescence. Because adolescence is a critical developmental period during which persistent pain conditions can arise, we examined the effect of neonatal injury on nociception, social behavior, and response to morphine in adolescent Sprague Dawley rats. ⋯ Neonatal injury did not alter acute morphine antinociception or the development of analgesic tolerance in either sex. Morphine-induced conditioned place preference, behavioral sensitization, and physical withdrawal were also not affected by neonatal incision. Thus, early-life injury results in sex-dependent pain-related hypersensitivity and social behavior deficits during adolescence, without altering the response to opioids.
-
Spontaneous pain and function-associated pain are prevalent symptoms of multiple acute and chronic muscle pathologies. We established mouse models for evaluating spontaneous pain and bite-evoked pain from masseter muscle, and determined the roles of transient receptor potential cation channel subfamily V member 1 (TRPV1) and the contribution of TRPV1- or neurokinin 1 (NK1)-dependent nociceptive pathways. Masseter muscle inflammation increased Mouse Grimace Scale scores and face-wiping behavior, which were attenuated by pharmacological or genetic inhibition of TRPV1. ⋯ Furthermore, ablation of neurons expressing NK1 receptor in trigeminal subnucleus caudalis also prevented both types of muscle pain. Our results suggest that TRPV1 differentially contributes to spontaneous pain and bite-evoked muscle pain, but TRPV1-expressing afferents and NK1-expressing second-order neurons commonly mediate both types of muscle pain. Therefore, manipulation of the nociceptive circuit may provide a novel approach for management of acute or chronic craniofacial muscle pain.
-
Review Meta Analysis
The relationship between Pacing and Avoidance in Chronic Pain: A Systematic Review and Meta-analysis.
Activity pacing is ubiquitous in chronic pain management and aims to reduce pain-contingent avoidance of activity to improve functioning. A meta-analysis, however, has linked pacing with higher levels of pain and disability. One potential explanation is an overlap between existing measures of pacing and avoidance, leading to links with poorer outcomes that are typically associated with avoidance. This study systematically reviews the evidence regarding the relationship between measures of pacing and avoidance. A search was conducted for studies measuring both constructs in adults with chronic pain. A meta-analysis of correlations between pacing and avoidance was conducted; 16 studies were included and a small positive correlation was found (r = .290, P < .001) overall. Single-item and multiple-item measures were also compared; a moderate positive correlation was found for multiple-item measures (r = .410, P < .001), which differed significantly from a small positive correlation found for single-item measures (r = .105, P < .001). Due to limited studies, independent analyses of individual subscales were not possible. Existing measures of pacing-particularly multiple-item measures-may partially confound pacing with avoidance. Further research is required to ensure that a reliable measure of pacing that distinguishes this construct from avoidance is available to adequately evaluate pacing instruction and the effect of pacing on key outcomes in chronic pain. ⋯ This meta-analysis examines the correlation between pacing and avoidance in adults with chronic pain. Results indicate that existing measures may partially confound pacing with avoidance. Directions for future research are proposed to ensure that an adequate measure of pacing exists to evaluate its effect on key outcomes in chronic pain.
-
There is increasing evidence that contextual forms of cognitive-behavioral therapy (CBT) are effective in the management of chronic pain, yet little is understood about the factors that moderate or predict outcomes in these treatments. This systematic review aimed to identify pretreatment participant characteristics associated with positive treatment responses in contextual CBT for chronic pain. Medline, EMBASE, PsychINFO, and CENTRAL were searched to identify eligible studies. Studies were included if the participants were adults with chronic pain, designs were longitudinal, treatments focused on psychological flexibility or mindfulness, and reported results allowed for examination of moderators or predictors of standard treatment outcomes. Of 991 records initially identified, 20 were eligible for inclusion in the review. Some evidence suggested that baseline emotional functioning predicts treatment response, but the direction of this association varied between studies. Substantive findings were inconsistent and inconclusive, however, methodological limitations were consistent. These included treatment heterogeneity, and a lack of theoretical, a priori guidance in examining potential predictors. Future research should adopt a theoretically based approach to examining moderators in relation to specific treatment methods and therapeutic processes. Considering moderation without first considering mediation is probably a limited strategy. ⋯ In this systematic review we examined evidence for potential predictors or moderators of outcomes in contextual CBT for chronic pain. Substantive findings were inconclusive but important methodological limitations and a lack of theoretical guidance were found. Future research should explicitly plan relevant methods and follow clear theoretical models.