European journal of pain : EJP
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The spinal cord is a prime site of action for analgesia. Here we characterize the effects of established analgesics on segmental spinal reflexes. The aim of the study was to look for the pattern of action or signature of analgesic effects on these reflexes. ⋯ morphine and duloxetine had general depressant effects on spinal reflexes, whereas the effects of clonidine, pregabalin and S1RA appeared to be restricted to signals originated by strong repetitive activation of C-fibres. Results are discussed in the context of reported behavioural effects of the compounds studied.
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This work summarizes the efficiency, failures and adverse effects of oral administration of ketamine at home for intractable pain. ⋯ Pain was reduced or abolished in two-thirds of patients under ketamine therapy; ketamine was effective for patients taking opioids and resulted in few adverse effects.
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Increased apoptotic changes in the spinal cord may be responsible for the development of chronic constriction injury (CCI)-induced neuropathic pain. We previously reported the beneficial effect of hyperbaric oxygen (HBO) in the treatment of CCI-induced neuropathic pain. In this study, we tested our hypotheses that HBO may achieve its beneficial effect by inhibiting CCI-induced proapoptosis gene expression and apoptosis in the spinal cord. ⋯ Overly expressed proapoptosis genes, and subsequent increase in spinal apoptotic cells, seem to contribute to the development of CCI-induced neuropathic pain. The inhibitory role of HBO on spinal proapoptosis genes and apoptotic changes may contribute to its beneficial effect on CCI-induced neuropathic pain.
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The development of antinociceptive tolerance following repetitive administration of opioid analgesics significantly hinders their clinical use. Evidence has accumulated indicating that microglia within the spinal cord play a critical role in morphine tolerance. The present study investigated the effects and possible mechanisms of a natural compound, paeoniflorin, in morphine tolerance via its specific inhibition of microglial activation. ⋯ Paeoniflorin directly suppresses morphine-induced microglial activation and thus results in potentiation of morphine acute analgesia and attenuation of morphine chronic antinociceptive tolerance.