Articles: hyperalgesia.
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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.
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Br J Clin Pharmacol · Sep 2005
Oral opioid administration and hyperalgesia in patients with cancer or chronic nonmalignant pain.
Previous research has reported on reduced paw withdrawal latencies to heat and mechanical stimuli after parenteral administration of opioids in animals and on increased pain sensitivity in humans subsequent to postoperative infusions of short-acting opioids or in drug addicts. The aim of the present study was to explore the possibility that oral opioid treated patients with cancer-related or chronic nonmalignant pain differ in their pain sensitivity from patients treated with non-opioid analgesics. ⋯ These results suggest that the administration of 'commonly used' dosages of oral opioids does not result in abnormal pain sensitivity beyond that of patients receiving non-opioid analgesia.
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The aim of the study was to determine the frequency of clinical allodynia, osmophobia and red ear syndrome in a young population. Medical records of the children admitted for headache between 1 December 2004 and 31 March 2005 were consecutively studied. A questionnaire was used to find the prevalence of allodynia, osmophobia and red ear syndrome. ⋯ We classified migraine in 57%, other primary headaches in 25% and secondary headaches in about 18%. The presence of ipsilateral clinical allodynia was 14.5% in migraine, osmophobia in 20% of migraine and red ear syndrome in about 24% of migraine cases and they were absent in the other two headache groups. Our study shows that features like osmophobia, allodynia and red ear syndrome are not uncommon in migraine while they are absent in other types of headache.
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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.