Pain
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Meta Analysis
Investigation of neuropathic pain in treated leprosy patients in Ethiopia: a cross-sectional study.
Pain can be a significant problem for treated leprosy patients. It can be nociceptive due to tissue inflammation occurring during episodes of immune mediated reactions, or neuropathic due to leprosy affecting the somatosensory system. There are sparse epidemiological data on the prevalence and impact of neuropathic pain in treated leprosy patients. ⋯ We have validated the use of DN4 in leprosy and it is easier to use than LANSS. Depression is a common co-morbidity in patients with NP. The high prevalence and morbidity of NP in treated leprosy patients warrant clinical trials to assess the efficacy of pain therapies for leprosy-associated NP.
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Inflammatory thermal hyperalgesia is principally mediated through transient receptor potential vanilloid 1 (TRPV1) channels, as demonstrated by prior studies using models of cutaneous inflammation. Muscle pain is significantly different from cutaneous pain, and the involvement of TRPV1 in hyperalgesia induced by muscle inflammation is unknown. We tested whether TRPV1 contributes to the development of mechanical and heat hypersensitivity of the paw in TRPV1(-/-) mice after muscle inflammation. ⋯ Heat hypersensitivity induced by muscle inflammation did not develop in TRPV1(-/-) mice; mechanical hypersensitivity was similar between TRPV1(-/-) and TRPV1(+/+) mice. Heat hypersensitivity induced by muscle inflammation was restored by reexpression of TRPV1 into both muscle and skin of TRPV1(-/-) mice. These results suggest that TRPV1 serves as both a mediator of nociceptor sensitization at the site of inflammation and as a heat sensor at the paw.
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Chronic pain is a multidimensional experience that not only includes changes in nociception, but also impairments in emotion and cognitive functions. These last 2 components are not often taken into account in preclinical research. We investigated emotional and cognitive impairments in a model of neuropathic pain in rats induced by chronic constriction injury (CCI) of the sciatic nerve. ⋯ Duloxetine and gabapentin (10mg/kg) were effective to increase the time spent in the inner zone as well as locomotor activity. No difference was observed in depressive-like behaviour (saccharin preference test) between sham-operated and CCI rats. These data suggest that cognitive rather than emotional impairments seem to be present in neuropathic CCI rats and can be reversed by duloxetine and gabapentin.