European journal of pain : EJP
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Clinical observations indicate that cutaneous hyperalgesia may arise from pain located in deep structures. The objective of this study was to investigate whether combined sensitization of deep and superficial somatic tissues facilitates skin hyperalgesia. ⋯ Using skin and deep tissue pain sensitization models simultaneously, no significant synergistic effects were found within the 3-day investigation suggesting little integration between the two phenomena in this period.
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Endometriosis is a common cause of pain including radicular pain. Ectopic endometrial tissue may directly affect peripheral nerves including the sciatic, which has not been modelled in animals. ⋯ Some especially painful forms of endometriosis are essentially neuropathic, because peripheral nerves are directly affected by nearby ectopic endometrial tissue. We modelled endometriosis by implanting autologous uterine tissue around rat sciatic nerve. We observed mechanical and cold pain behaviours along with signs of inflammation and nerve damage and increased pro-inflammatory cytokines at the implant site. Pain behaviours correlated with signs of nerve inflammation and damage rather than with cyst survival.
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Widespread musculoskeletal pain (WSP) and obesity frequently co-occur and may have shared risk factors. We aimed to investigate whether four dichotomized risk factors individually or jointly increase the risk for the onset of WSP and onset of obesity. ⋯ The onset of WSP and the onset of obesity were results of joint effects of exposures. Poor physical fitness was a key covariate in increasing the risk for both conditions. WHAT DOES THIS STUDY ADD?: In a general population, the new onset of widespread pain and new onset of obesity were results of joint effects of risk factors and particularly poor physical fitness. The study may aid in the identification of patients at risk of future disability.
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Numerous studies have found appraisals of pain as a source of potential threat or tissue damage influence pain perception and coping. Conversely, causal effects of challenge appraisals reflecting potential future benefits of bearing pain have received little attention. This experiment was designed to elucidate effects of appraising laboratory pain as a source of potential threat and challenge on pain perception and coping. ⋯ Findings underscore causal effects of pain appraisals on coping responses and pain perception. WHAT DOES THIS STUDY ADD?: Effects of challenge appraisals of pain as a source of potential future growth or development have not been considered in experimental pain research. Causal effects of primary appraisals of laboratory pain as a source of potential threat and challenge were elucidated in relation to pain perception and coping.
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Although polymorphisms of the catechol-O-methyl transferase (COMT) gene have been implicated in altered pain sensitivity, results concerning the association between COMT gene polymorphisms and fibromyalgia (FM) are equivocal. We assessed the associations between COMT single-nucleotide polymorphisms (SNP) and FM risk and symptom severity. ⋯ By contrast to Caucasian and Latin-American populations, the COMT gene polymorphisms are associated with FM risk and pain sensitivity in Korean FM patients, suggesting ethnic variation in COMT gene polymorphisms.