European journal of pain : EJP
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Up-regulation of transient receptor potential vanilloid subfamily, member 1 (TRPV1) is associated with the development and maintenance of cancer pain. The present study aimed to investigate the electrophysiological function of the up-regulated TRPV1 and the potential regulatory effects of insulin-like growth factor-1 (IGF-1) on TRPV1 expression in peripheral nerves in a rat model of bone cancer pain. ⋯ Our results provide novel evidence for the increase of IGF-1 in tibia bone marrow, which is responsible for the up-regulation of TRPV1 expression and function in the peripheral nerves of bone cancer pain rats.
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Control of trunk movement relies on the integration between central neuronal circuits and peripheral skeletomuscular activities and it can be altered by pain. There is increasing evidence that there are deficits within the central nervous system controlling the trunk muscles in people with low back pain (LBP). However, it is unclear how LBP impacts upon neural drive to back muscles at different levels of voluntary contraction. Therefore, the purpose of this study was to investigate if neural drive is impaired in these patients. ⋯ A decline of central neural drive to the back muscles at high level of voluntary contraction was observed in patients with LBP. These results suggest that it might be pertinent to include neuromuscular facilitation programmes and therapeutic exercise utilizing high voluntary contractions for patients with LBP.
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Both nerve growth factor (NGF) and ultraviolet-B (UV-B) irradiation sensitize nociceptive nerve endings and increase axonal excitability of nociceptors. Combining NGF and UV-B treatment is supra-additive for sensory sensitization and even caused spontaneous pain in about 70% of the subjects. ⋯ The combination of NGF and UV-B increases axonal excitability that contributes to hyperalgesia and might also facilitate ongoing spontaneous pain.