Articles: hyperalgesia.
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Zhonghua yi xue za zhi · Jan 2013
Clinical Trial[Effect of dexmedetomidine in acute postoperative pain relief is independent of suppressing the hyperalgesia induced by remifentanil].
To explore the effect of dexmedetomidine in acute postoperative pain and remifentanil-induced hyperalgesia. ⋯ Dexmedetomidine can alleviate the acute postoperative pain effectively, but the effect is not dependent on inhibiting remifentanil-induced hyperalgesia.
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S-(+)-dicentrine is an aporphinic alkaloid found in several plant species, mainly from Lauraceae family, which showed significant antinociceptive activity in an acute model of visceral pain in mice. In this work, we extended the knowledge on the antinociceptive properties of S-(+)-dicentrine and showed that this alkaloid also attenuates mechanical and cold hypersensitivity associated with cutaneous inflammation induced by Complete Freund's Adjuvant in mice. Given orally, S-(+)-dicentrine (100 mg/kg) reversed CFA-induced mechanical hypersensitivity, evaluated as the paw withdrawal threshold to von Frey hairs, and this effect lasted up to 2 hours. ⋯ When administered either by oral or intraplantar routes, S-(+)-dicentrine reduced the licking time (spontaneous nociception) and increased the latency time to paw withdrawal in the cold plate (cold hypersensitivity), both induced by the intraplantar injection of cinnamaldehyde. Taken together, our data adds information about antinociceptive properties of S-(+)-dicentrine in inflammatory conditions, reducing spontaneous nociception and attenuating mechanical and cold hypersensitivity, probably via a TRPA1-dependent mechanism. It also indicates that S-(+)-dicentrine might be potentially interesting in the development of new clinically relevant drugs for the management of persistent pain, especially under inflammatory conditions.
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Mol. Cell. Neurosci. · Jan 2013
Neuronal IL-17 receptor upregulates TRPV4 but not TRPV1 receptors in DRG neurons and mediates mechanical but not thermal hyperalgesia.
In addition to the proinflammatory cytokines tumor necrosis factor-α, interleukin-6 and interleukin-1ß, the cytokine interleukin-17 (IL-17) is considered an important mediator of autoimmune diseases such as rheumatoid arthritis. Because tumor necrosis factor-α and interleukin-1ß have the potential to influence the expression of transduction molecules such as transient receptor potential vanilloid 1 (TRPV1) in dorsal root ganglion (DRG) neurons and thus to contribute to pain we explored in the present study whether IL-17A activates DRG neurons and influences the expression of TRPV1. The IL-17A receptor was visualized in most neurons in dorsal root ganglion (DRG) sections as well as in cultured DRG neurons. ⋯ However, we found a pronounced upregulation of transient receptor potential vanilloid 4 (TRPV4) which is considered a candidate transduction molecule for mechanical hyperalgesia. Upon the injection of zymosan into the paw, IL-17A-deficient mice showed less mechanical hyperalgesia than wild type mice but thermal hyperalgesia was not attenuated in IL-17A-deficient mice. These data show, therefore, a particular role of IL-17 in mechanical hyperalgesia, and they suggest that this effect is linked to an activation and upregulation of TRPV4.
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Uropathogenic Escherichia coli (UPEC) are pathogens that play an important role in urinary tract infections and bacterial prostatitis. We have recently shown that UPEC have an important role in the initiation of chronic pelvic pain, a feature of Chronic prostatitis/Chronic pelvic pain syndrome (CP/CPPS). Infection of the prostate by clinically relevant UPEC can initiate and establish chronic pain through mechanisms that may involve tissue damage and the initiation of mechanisms of autoimmunity. ⋯ An irritable focus in visceral tissues reduces cutaneous pain thresholds allowing for an exaggerated response to normally non-painful stimuli (allodynia). Application of normal force to the skin result in abnormal responses that tend to increase with the intensity of the underlying visceral pain. We describe methodology in NOD/ShiLtJ mice that utilize von Frey fibers to quantify tactile allodynia over time in response to a single infection with UPEC bacteria.
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We investigated the influence of morphine and ketamine or clonidine in mice on the expression of genes that may mediate pronociceptive opioid effects. ⋯ The results indicate that co-administration of clonidine or ketamine may influence the underlying mechanisms of OIH.