Articles: chronic-pain.
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Proc. Natl. Acad. Sci. U.S.A. · Jan 2012
An antinociceptive role for substance P in acid-induced chronic muscle pain.
Release of substance P (SP) from nociceptive nerve fibers and activation of its receptor neurokinin 1 (NK1) are important effectors in the transmission of pain signals. Nonetheless, the role of SP in muscle pain remains unknown. Here we show that a single i.m. acid injection in mice lacking SP signaling by deletion of the tachykinin precursor 1 (Tac1) gene or coadministration of NK1 receptor antagonists produces long-lasting hyperalgesia rather than the transient hyperalgesia seen in control animals. ⋯ Furthermore, the SP signaling could alter action potential thresholds and modulate the expression of TTX-resistant sodium currents in medium-sized muscle nociceptors. Thus, i.m. SP mediates an unconventional NK1 receptor signal pathway to inhibit acid activation in muscle nociceptors, resulting in an unexpected antinociceptive effect against chronic mechanical hyperalgesia, here induced by repeated i.m. acid injection.
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Randomized Controlled Trial Multicenter Study
Cognitive behavior therapy, exercise, or both for treating chronic widespread pain.
The clinical impact of telephone-delivered cognitive behavioral therapy (TCBT), exercise, or a combined intervention in primary care patients with chronic widespread pain (CWP) is unclear. ⋯ TCBT was associated with substantial, statistically significant, and sustained improvements in patient global assessment.
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Functional neuroimaging studies have implicated the prefrontal cortex (PFCTX) in descending modulation of pain and the placebo effect. This study was performed to elucidate comprehensive PFCTX gene expression in an animal model of persistent trigeminal pain. Adult male C57BL/6J mice received facial carrageenan injection and showed sustained increase in nociceptive responses. ⋯ Approximately 70% of S100A9-positive cells in the PFCTX of carrageenan-injected mice were located in capillaries adherent to endothelial cells, whereas 30% were within the brain parenchyma. Carrageenan-injected mice showed significantly reduced nociceptive responses after injection of C terminus of murine S100A9 protein in the lateral ventricles and PFCTX but not somatosensory barrel cortex. Together, these findings demonstrate activation of immune-related genes in the PFCTX during inflammatory pain and highlight an exciting role of neutrophils in linking peripheral inflammation with immune activation of the PFCTX and antinociception.
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Comparative Study
The benzomorphan-based LP1 ligand is a suitable MOR/DOR agonist for chronic pain treatment.
Powerful analgesics relieve pain primarily through activating mu opioid receptor (MOR), but the long-term use of MOR agonists, such as morphine, is limited by the rapid development of tolerance. Recently, it has been observed that simultaneous stimulation of the delta opioid receptor (DOR) and MOR limits the incidence of tolerance induced by MOR agonists. 3-[(2R,6R,11R)-8-hydroxy-6,11-dimethyl-1,4,5,6-tetrahydro-2,6-methano-3-benzazocin-3(2H)-yl]-N-phenylpropanamide (LP1) is a centrally acting agent with antinociceptive activity comparable to morphine and is able to bind and activate MOR and DOR. The aim of this work was to evaluate and compare the induction of tolerance to antinociceptive effects from treatment with LP1 and morphine. ⋯ LP1 is a novel analgesic agent for chronic pain treatment, and its low tolerance-inducing capability may be correlated with its ability to bind both the MOR and DOR.
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Int J Clin Exp Hypn · Jan 2012
ReviewHypnosis for the management of chronic and cancer procedure-related pain in children.
The aim of this study was to review published controlled trials of hypnotic treatments for chronic and cancer procedure-related pain in children. Trials were included if participants were 18 years of age or below, were randomized and had populations with chronic pain or cancer procedure-related pain. ⋯ Although the evidence is limited, the findings indicate that hypnosis is an effective pain-control technique when used with children suffering from cancer procedure-related pain or chronic pain. Further research into the use of hypnosis to manage chronic pain in children should be a priority so that empirically based conclusions can be drawn about the effects of hypnosis on children.