Articles: hyperalgesia.
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Comparative Study
Activation of p38 MAPK in primary afferent neurons by noxious stimulation and its involvement in the development of thermal hyperalgesia.
Alterations in the intracellular signal transduction pathway in primary afferents may contribute to pain hypersensitivity. We demonstrated that very rapid phosphorylation of p38 mitogen-activated protein kinase occurred in dorsal root ganglion (DRG) neurons that were participating in the transmission of noxious signals. Capsaicin injection induced phosphorylated-p38 (p-p38) in small-to-medium diameter sensory neurons with a peak at 2 min after capsaicin injection. ⋯ Intrathecal administration of the p38 inhibitor, FR167653, reversed the thermal hyperalgesia produced by the capsaicin injection. Inhibition of p38 activation was confirmed by the decrease in the number of p-p38-IR neurons in the DRG following capsaicin injection. Taken together, these findings suggest that the activation of p38 pathways in primary afferents by noxious stimulation in vivo may be, at least in part, correlated with functional activity, and further, involved in the development of thermal hyperalgesia.
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The present study was conducted to test the hypothesis that the peripheral 5-hydroxytryptamine (5-HT)2A receptor is involved in inflammatory hyperalgesia and production of noxious stimulus-induced neuronal activity at the level of the spinal cord dorsal horn. Intraplantar (i.pl.) injection of carrageenan dramatically reduced paw withdrawal latency to noxious heat (47 degrees C) and caused paw swelling. Pretreatment with ketanserin, a selective antagonist of 5-HT2A receptor, in the hindpaw produced dose-dependent inhibition of the hyperalgesia (0.5, 3 and 5 mug; i.pl.) with full relief at 5 mug. ⋯ Ketanserin (5 mug) markedly reduced carrageenan-induced FLI in all laminae of the dorsal horn. However, blockade of peripheral 5-HT1A receptors by (N-2-[4-(2-methoxyphenyl-1-piperazinyl] ethyl]-N-2-pyridinylcyclohexanecarboxamide at maximally effective doses (30 and 100 mug; i.pl.) did not alter carrageenan-induced hyperalgesia, edema or expression of FLI. The present study provided evidence at cellular level that the peripheral 5-HT2A receptor is preferentially involved in the development of thermal hyperalgesia in the carrageenan model of inflammation.
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Randomized Controlled Trial Comparative Study Clinical Trial
Psychophysical outcomes from a randomized pilot study of manual, electro, and sham acupuncture treatment on experimentally induced thermal pain.
In this pilot study comparing the analgesic effects of three acupuncture modes--manual, electro, and placebo (with Streitberger placebo needles)--in a cohort of healthy subjects, we found that verum acupuncture treatment, but not placebo, lowered pain ratings in response to calibrated noxious thermal stimuli. This finding was mainly the result of highly significant analgesia in 5 of the 11 subjects who completed the 5-session study. Of the 5 responders, 2 responded only to electroacupuncture and 3 only to manual acupuncture, suggesting that acupuncture's analgesic effects on experimental pain may be dependent on both subject and mode. We developed a simple quantitative assessment tool, the Subjective Acupuncture Sensation Scale (SASS), comprised of 9 descriptors and an anxiety measure to study the relationship between the deqi sensation induced by acupuncture and the putative therapeutic effects of acupuncture. The SASS results confirm that the deqi sensation is complex, with all subjects rating multiple descriptors during each mode. We found significant correlations of analgesia with SASS ratings of numbness and soreness, but not with ratings of stabbing, throbbing, tingling, burning, heaviness, fullness, or aching. This suggests that attributes of the deqi sensation may be useful clinical indicators of effective treatment. ⋯ The results of this study indicate the existence of both individual subject and acupuncture mode variability in the analgesic effects of acupuncture. This suggests that switching acupuncture mode may be a treatment option for unresponsive patients.
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Our aims were to determine whether subjects with painful bladder syndrome (PBS) demonstrate characteristics of visceral pain syndromes: visceral hyperalgesia, expanded loci of referral of bladder sensation, increased bladder pain with repetitive filling, lower thresholds to cutaneous stimulation in relevant dermatomes, abnormal response to repetitive cutaneous stimulation in relevant dermatomes, and also to develop easily applied measures for PBS pain evaluation and management. ⋯ PBS subjects demonstrate bladder hyperalgesia and may sense bladder discomfort at sites other than suprapubic. Rating of bladder discomfort and sensory mapping during cystometry usefully distinguishes between PBS subjects and controls.
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Schweiz Monatsschr Zahnmed · Jan 2005
[Therapeutic local anesthesia for the management of atypical odontalgia. A clinical case series].
The management of patients diagnosed with atypical odontalgia (AO) is a challenging task. The aim of this longitudinal clinical case series was to document the effect of a 4% carticaine solution without epinephrine among ten patients with AO. Once or on two successive days, 1.7 ml of the local anesthetics was injected buccally in the area of the perceived pain. ⋯ Patient satisfaction was not significantly associated with the amount of pain reduction. Considering the limited treatment options and their side effects, injections with epinephrine-free carticaine seem to be a measure worth to be taken into consideration. Although results gained from uncontrolled case series have to be interpreted with caution, the findings of this observational study sound promising.