Pain
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Patients with the same neuropathic pain disorder may have completely different sensory signs and symptoms yet receive the same medicinal treatment. New concepts suggest that patient stratification according to their pain mechanisms, reflected in their sensory phenotype, could be promising to implement an individualized therapy in neuropathic pain. ⋯ Recent prospective studies using stratification based on sensory phenotypes confirm this concept. In this article, we review the recent accomplishments towards an individualized pharmacological treatment of neuropathic pain.
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The sodium channel NaV1.7 contributes to action potential (AP) generation and propagation. Loss-of-function mutations in patients lead to congenital indifference to pain, though it remains unclear where on the way from sensory terminals to central nervous system the signalling is disrupted. We confirm that conditional deletion of NaV1.7 in advillin-expressing sensory neurons leads to impaired heat and mechanical nociception in behavioural tests. ⋯ On prolonged electrical stimulation at 2 Hz, (7) activity-dependent slowing of nerve fiber conduction was markedly less, and (8) was less likely to result in conduction failure of the mutant single fibers. Finally, recording of compound APs from the whole saphenous nerve confirmed slower conduction and less activity-dependent slowing as well as the functional absence of a large subpopulation of C-fibers (9) in conditional NaV1.7 knockouts. In conclusion, the clear deficits in somatic primary afferent functions shown in our study may be complemented by previously reported synaptic dysfunction and opioidergic inhibition, together accounting for the complete insensitivity to pain in the human mutants lacking NaV1.7.
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Neuropathic itch is a pathological condition that is due to damage within the nervous system. This type of itch can be severe and unrelenting, which has a very negative impact on quality of life. ⋯ Unfortunately, much like neuropathic pain, there is a lack of effective treatments for neuropathic itch. Here, we consider the neural basis of itch and then describe how injuries within these neural circuits can lead to neuropathic itch in both animal models and human disease states.
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There is little information on the impact of pain on sexual health in later life. The aim of this analysis was to determine the association between self-reported pain and sexual health in older men and women. Data were collected for the nationally representative English Longitudinal Study of Ageing. ⋯ After age adjustment, there were no associations between pain severity and sexual health among women. Of the 1872 participants with a cumulative pain score, there were significant associations between reporting pain and concerns about sexual health in both men and women. Pain was associated with impairment in sexual health in men and women; however, the effect was more marked in men.