European journal of pain : EJP
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Gender role expectations of pain (GREP) have been shown to mediate sex differences in experimental pain. Few studies have investigated the role of ethnicity in shaping GREP. The aim of this study was to examine interactions between ethnicity and GREP on experimentally induced pressure and ischaemic pain in Libyan and white British students in their respective countries. ⋯ GREP was the mediator of sex but not ethnic differences in pain report, suggesting that gender stereotypical attitudes to pain account for differences in pain expression between men and women.
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β-caryophyllene (BCP) is a common constitute of the essential oils of numerous spice, food plants and major component in Cannabis. The present study investigated the contribution of peripheral cannabinoid (CB) and opioid systems in the antinociception produced by intraplantar (i.pl.) injection of BCP. The interaction between peripheral BCP and morphine was also examined. ⋯ The present results demonstrate that antinociception produced by i.pl. BCP is mediated by activation of CB2 receptors, which stimulates the local release from keratinocytes of the endogenous opioid β-endorphin. The combined injection of morphine and BCP may be an alternative in treating chemogenic pain.
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Microglia serve as macrophage-like cells in the central nervous system, and activation of microglial cells in the spinal cord may contribute to ongoing pain following peripheral trauma or nerve injury. Following pronociceptive stimulation, activated microglia exhibit increased expression of the peripheral benzodiazepine receptor (PBR)/translocator protein 18 kDa (TSPO). ⋯ These studies demonstrate that [(3)H]PK11195 binding assays may serve as a marker of spinal microglial activation in experimental models of chronic neuropathic or osteoarthritic pain, which may be translatable to clinical research through novel applications of PBR/TSPO imaging agents.
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Neutrophil recruitment mediated by the CXCL1/KC chemokine and its receptors CXCR1/CXCR2 plays a critical role in inflammatory diseases. Recently, neutrophil migration and activation triggered by CXCL1-CXCR1/2 signalling was implicated in inflammatory nociception; however, their role in post-surgical pain has not been elucidated. In this study, we addressed the function of neutrophils in the genesis of post-incisional pain in an experimental model of post-surgical pain. ⋯ In conclusion, it appears that after surgical processes, neutrophils are recruited by CXCL1-CXCR1/2 signalling and participate in the cascade of events, leading to mechanical hyperalgesia. These results suggest that blocking neutrophil migration through the inhibition of CXCL1-CXCR1/2 signalling might be a target to control post-surgical pain.
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Chemotherapy-induced peripheral neuropathy is a serious side effect in cancer treatment, a major manifestation being neuropathic pain that can be debilitating and can reduce the quality of life of the patient. Oxaliplatin and taxol are common anti-cancer drugs that induce neuropathic pain by an unknown mechanism. We tested the hypothesis that satellite glial cells in dorsal root ganglia (DRGs) are altered in chemotherapy-induced peripheral neuropathy models and contribute to neuropathic pain. ⋯ We propose that increased coupling by gap junctions is part of satellite glial cell activation, and that augmented coupling contributes to the lowering of pain threshold in oxaliplatin- and taxol-treated mice. We further propose that gap junction blockers may have potential in treating chemotherapy-induced neuropathic pain.