Articles: hyperalgesia.
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Controlled Clinical Trial
Increased contact heat pain and shortened latencies of contact heat evoked potentials following capsaicin-induced heat hyperalgesia.
To examine changes in contact heat evoked potentials (CHEPs) and perceived pain intensity following acute sensitization with topical capsaicin. ⋯ Contact heat may be a useful tool to assess sensitization of the pain system.
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Widespread deep tissue pain hyperalgesia was evaluated in women with chronic whiplash associated disorder (n = 25) and controls (n = 10) using computerized cuff pressure algometry and hypertonic saline infusion. ⋯ The results indicated widespread hyperalgesia in chronic whiplash associated disorder and facilitated temporal summation outside the primary pain area, suggesting involvement of central sensitization.
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The NMDA and TRPV1 receptors that are expressed in sensory neurons have been independently demonstrated to play important roles in peripheral pain mechanisms. In the present study, we investigated whether the 2 receptor-channel systems form a functional complex that provides the basis for the development of mechanical hyperalgesia. In the masseter muscle, direct application of NMDA induced a time-dependent increase in mechanical sensitivity, which was significantly blocked when the muscle was pretreated with a specific TRPV1 antagonist, AMG9810. ⋯ Consistent with the biochemical data, the NMDA-induced mechanical hyperalgesia was also effectively blocked when the muscle was pretreated with a CaMKII or PKC inhibitor. Thus, NMDA receptors and TRPV1 functionally interact via CaMKII and PKC signaling cascades and contribute to mechanical hyperalgesia. These data offer novel mechanisms by which 2 ligand-gated channels in sensory neurons interact and reinforce the notion that TRPV1 functions as a signal integrator under pathological conditions.
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Reg Anesth Pain Med · Jul 2012
Sciatic nerve block fails in preventing the development of late stress-induced hyperalgesia when high-dose fentanyl is administered perioperatively in rats.
: Sciatic nerve block fails in preventing the development of late stress-induced hyperalgesia (SIH) when high-dose fentanyl is administered perioperatively in rats. ⋯ Perioperative use of long-lasting RA reduced both acute postoperative hyperalgesia and the development of long-term pain vulnerability. However, high doses of fentanyl for intraoperative analgesia induce central sensitization that cannot be reversed by using long-lasting RA.
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Anesthesia and analgesia · Jul 2012
Comparative StudyThe efficacy of morphine, pregabalin, gabapentin, and duloxetine on mechanical allodynia is different from that on neuroma pain in the rat neuropathic pain model.
It has been reported that <50% of neuropathic pain patients are satisfactorily treated with drugs. It is possible that this lack of efficacy of drugs on neuropathic pain might be due to the drugs prescribed, regardless of the origin of pain. We compared the efficacy of orally administered morphine, pregabalin, gabapentin, and duloxetine on mechanical allodynia with that on neuroma pain using the tibial neuroma transposition (TNT) model. ⋯ These data indicate that the potency of morphine and the efficacy of pregabalin, gabapentin, and duloxetine on mechanical allodynia are different from those on neuroma pain and that combination therapy is one of different therapeutic choices for the treatment of neuropathic pain.