Robinson-Vanderwerf T M, Di Pirro J M, Caggiula A R, Kristal M B
Department of Psychology, University at Buffalo, NY 14260, USA.
Pharmacol Biochem Behav. 1997 Sep;58(1):147-51. doi: 10.1016/s0091-3057(97)00006-3.
Ingestion of amniotic fluid and placenta by rats has been shown to enhance opioid-mediated antinociception but not affect the nonopioid-mediated antinociception produced by aspirin, suggesting specificity for opioid-mediated processes. However, enhancement by the active substance(s) in amniotic fluid and placenta (POEF, for placental opioid-enhancing factor) of antinociception produced by other nonopioid mechanisms has yet to be examined. The present experiments tested whether ingestion of amniotic fluid enhances the antinociception produced by nicotine injection. In Experiment 1A, enhancement of morphine-mediated antinociception by ingestion of amniotic fluid was demonstrated in a hot-plate assay. In Experiment 1B, rats pretreated with naltrexone were given an orogastric infusion of amniotic fluid or control (0.25 ml), then injected with nicotine (0, 0.075, 0.125, or 0.225 mg/kg subcutaneously), then tested for antinociception in a hot-plate assay. Amniotic fluid ingestion did not enhance the antinociception produced by various doses of nicotine. In Experiment 2, rats pretreated with naltrexone were given an orogastric infusion of amniotic fluid (0, 0.125, 0.25, or 0.50 ml) and then injected with 0.125 mg/kg nicotine. None of the doses of amniotic fluid enhanced the nicotine-induced antinociception. The findings of these experiments lend support to our contention that the enhancement by POEF of antinociception is specific to opioid-mediated processes.
已表明大鼠摄入羊水和胎盘可增强阿片类药物介导的镇痛作用，但不影响阿司匹林产生的非阿片类药物介导的镇痛作用，这表明对阿片类药物介导的过程具有特异性。然而，羊水和胎盘（POEF，胎盘阿片增强因子）中的活性物质对其他非阿片类机制产生的镇痛作用的增强作用尚未得到研究。本实验测试了摄入羊水是否会增强尼古丁注射产生的镇痛作用。在实验1A中，在热板试验中证明了摄入羊水可增强吗啡介导的镇痛作用。在实验1B中，用纳曲酮预处理的大鼠经口胃灌注羊水或对照（0.25 ml），然后皮下注射尼古丁（0、0.075、0.125或0.225 mg/kg），然后在热板试验中测试镇痛作用。摄入羊水并未增强不同剂量尼古丁产生的镇痛作用。在实验2中，用纳曲酮预处理的大鼠经口胃灌注羊水（0、0.125、0.25或0.50 ml），然后注射0.125 mg/kg尼古丁。所有剂量的羊水均未增强尼古丁诱导的镇痛作用。这些实验的结果支持了我们的观点，即POEF对镇痛作用的增强作用对阿片类药物介导的过程具有特异性。
