Quantitative sensory examination of epidural anaesthesia and analgesia in man: effects of pre- and post-traumatic morphine on hyperalgesia.

摘要: The objectives of the study were: (1) comparison hypoalgesic effects pre- and post-traumatic epidural morphine (EM) on primary secondary hyperalgesia, (2) EM hypoalgesia in normal injured skin. Burn injuries (25 x 50 mm rectangular thermode, 47 degrees C, 7 min) were produced calves healthy volunteers, at 2 different days least 1 week apart. In randomized order, subjects received 4 mg administered via L2-L3 intervertebral space one day no treatment other day. One calf was 30 min prior to 2.5 h after administration morphine. Hence, a model postinjury treatment, administration, pretraumatic treatment. timing identical control days. induced decrease heat pain detection tolerance thresholds within area injury (area hyperalgesia) as well reduction areas allodynia for brush pinprick surrounding hyperalgesia). Both increased thresholds, decreased by approximately 50% hyperalgesia postinjury. naloxone (NAL)-reversible (0.1 mg/kg, i.v.). There significant difference between effect either or hyperalgesia. threshold more than corresponding non-injured site. Following NAL, expanded beyond size. It is suggested that major inhibition C fibre-mediated activity which maintains altered response properties central neurons responsible Possible mechanisms action NAL enhancement are discussed.