European journal of pain : EJP
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The mechanisms underlying sex-based differences in pain and analgesia are poorly understood. In this study, we investigated gene expression changes in trigeminal ganglia (TG) of male and female rats exposed to infraorbital nerve chronic constriction injury (IoN-CCI). ⋯ We present novel sex-specific transcriptional regulation in trigeminal ganglia that may contribute to male-/female-based differences in trigeminal neuropathic pain. These findings are expected to open new research horizons, particularly in male versus female targeted therapeutic regimens.
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Prostaglandin E2 (PGE2) enriched in inflamed tissues contributes to chronic pain by sensitizing nociceptive dorsal root ganglion (DRG) neurons (nociceptors). Of four PGE2 receptors (EP1-4), EP4 plays a major role in PGE2-induced nociceptor sensitization. We have previously reported that PGE2 or EP4 agonists stimulated EP4 externalization in cultured DRG neurons and this event contributes to nociceptor sensitization. However, the signalling transduction events governing this event remain unknown. ⋯ This study adds mechanistic information regarding signalling transduction events involved in agonist-induced EP4 cell surface trafficking. EP4 and EP2 (to lesser extent) receptors, extra- and intracellular Ca++ , CaKMII, cAMP, PKA, PKC, PKCε, PLC, MAPK, PI3K and Akt are involved in this event. Agonist-induced EP4 externalization contributes to enhanced nociceptor sensitization.
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The evidence for Internet-delivered pain management programs for chronic pain is growing, but there is little empirical understanding of how they effect change. Understanding mechanisms of clinical response to these programs could inform their effective development and delivery. ⋯ This study employed robust statistical techniques to assess the psychological mechanisms of an established internet-delivered pain management program. While clinical improvements (e.g. depression, anxiety, pain) were closely associated with improvements in psychological variables (e.g. pain self-efficacy and pain acceptance), these variables do not appear to be treatment mechanisms.