Articles: hyperalgesia.
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Comparative Study
Increased nerve growth factor after rat plantar incision contributes to guarding behavior and heat hyperalgesia.
Acutely, nerve growth factor (NGF) exerts profound effects on nociceptive transmission and produces pain and hyperalgesia. In the present study, we sought to determine the tissue levels and role of NGF after a plantar incision. A substantial increase in NGF protein expression occurred in skin 4-h, 1-day and 2-days and 5-days after incision comparing contralateral uninjured skin. ⋯ In conclusion, increased NGF was present in skin after plantar incision. NGF contributes to some incision-induced pain behaviors, guarding and heat hyperalgesia. Anti-NGF did not affect the extent of sensitization of C-fibers observed in vitro.
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J. Neuropathol. Exp. Neurol. · Sep 2005
Comparative StudyInhibition of type 1 diabetic hyperalgesia in streptozotocin-induced Wistar versus spontaneous gene-prone BB/Worchester rats: efficacy of a selective bradykinin B1 receptor antagonist.
Insulin-dependent type 1 diabetes (T1D) is linked to a series of complications, including painful diabetic neuropathy (PDN). Several neurovascular systems are activated in T1D, including the inducible bradykinin (BK) B1 receptor (BKB1-R) subtype. We assessed and compared the efficacy profile of a selective BKB1-R antagonist on hyperalgesia in 2 models of T1D: streptozotocin (STZ) chemically induced diabetic Wistar rats and spontaneous BioBreeding/Worchester diabetic-prone (BB/Wor-DP) rats. ⋯ BB/Wor-DP rats also developed hyperalgesia over time that preceded hyperglycemia, starting at the age of 6 weeks (9% decrease in the hot plate reaction time) and stabilizing over the age of 16 to 24 weeks to a maximum (60% decrease in the hot plate reaction time). Single, acute subcutaneous administration of the selective BKB1-R antagonist induced significant time- and dose-dependent attenuation of hyperalgesia in both STZ diabetic and BB/Wor-DP rats. Thus, selective antagonism of the inducible BKB1-R subtype may constitute a novel and potential therapeutic approach for the treatment of PDN.
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Comparative Study Clinical Trial
The impact of ethnic differences in response to capsaicin-induced trigeminal sensitization.
Ethnic differences in the experience of pain, pain-related health care utilization and pain-reducing activities have been reported. Thus, evaluating of such variations is important in clinical and experimental pain. Since clinical pain is greatly influenced by disease-specific factors (severity, duration, type and treatment), evaluating ethnic differences in experimental pain models may not only provide some information about underlying mechanisms but also may predict or explain group differences in clinical pain. ⋯ Pain sensitivity, secondary hyperalgesic area, and pressure pain threshold were assessed. Overall, the model showed significant greater pain responses in South Indians (8.75+/-1.25 cm pain intensity and 9.33+/-2.32 cm2 hyperalgesic area) compared to Caucasians (6.25+/-1.95 cm pain intensity and 6.25+/-1.41 cm2 hyperalgesic area). The model may provide important information for further clinical research, e.g. migraine or differences in mechanisms underlying trigeminal sensitization.
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To describe the incidence and time course of dynamic mechanical allodynia (brush allodynia, BA) in an inpatient headache population. ⋯ BA is common in hospitalized headache patients. Subjects with more severe unilateral headaches were more likely to have BA. The presence of BA did not predict treatment failure in an inpatient setting.
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We developed a mouse model of cancer pain to investigate its underlying mechanisms. SCC-7, squamous cell carcinoma (SCC) derived from C3H mice, was inoculated subcutaneously into either the plantar region or thigh in male C3H/Hej mice. Heat and mechanical sensitivity as well as spontaneous behavior were measured at the plantar surface of the ipsilateral hind paw after the inoculation. ⋯ Intraperitoneal administration of the competitive TRPV1 antagonist capsazepine inhibited hyperalgesia induced by tumor cell-inoculation in either plantar- or thigh-inoculated animals. This study indicated that inoculation of SCC resulted in spontaneous pain, heat hyperalgesia and mechanical allodynia. The altered expression of TRPV1 in the DRG may be involved in behavioral changes in this model.