Backonja M M, Miletic G, Miletic V
Department of Neurology, University of Wisconsin School of Medicine, Madison 53706, USA.
Neurosci Lett. 1995 Aug 18;196(1-2):61-4. doi: 10.1016/0304-3940(95)11844-m.
We employed hindfoot withdrawal latencies to radiant heat to assess the analgesic effect of prolonged morphine infusion on thermal hyperalgesia induced by chronic constriction injury (CCI) of the rat sciatic nerve. All CCI rats developed thermal hyperalgesia while sham-operated animals did not. Continuous systemic infusion of morphine dose-dependently reversed the thermal hyperalgesia in the CCI rats. In contrast, thermal hyperalgesia persisted in saline-treated CCI rats. Tolerance to morphine's analgesic effect did not develop over a period of seven days of morphine infusion, which is considered long-term for animal models. These data suggest that morphine acts rapidly and effectively to reduce behavioral signs of hyperalgesia in rats with sciatic CCI, without the concomitant development of tolerance. Scheduled administration of morphine might be an appropriate treatment regimen for relief of neuropathic pain, and the infrequent use of opioids in equivalent human clinical pain syndromes due to fear of opioid unresponsiveness and tolerance might need to be re-evaluated.
我们采用后足对辐射热的缩腿潜伏期来评估长时间输注吗啡对大鼠坐骨神经慢性压迫损伤（CCI）诱导的热痛觉过敏的镇痛效果。所有CCI大鼠均出现热痛觉过敏，而假手术动物则未出现。持续全身性输注吗啡可剂量依赖性地逆转CCI大鼠的热痛觉过敏。相比之下，生理盐水处理的CCI大鼠的热痛觉过敏持续存在。在长达七天的吗啡输注期间，未出现对吗啡镇痛作用的耐受性，这在动物模型中被认为是长期的。这些数据表明，吗啡能迅速有效地减轻坐骨神经CCI大鼠的痛觉过敏行为体征，且不会同时产生耐受性。定时给予吗啡可能是缓解神经性疼痛的合适治疗方案，并且由于担心阿片类药物无反应性和耐受性，在等效的人类临床疼痛综合征中不常使用阿片类药物的情况可能需要重新评估。
