Grisel J E, Mogil J S
Department of Psychology, Furman University, 29613, Greenville, SC, USA.
Peptides. 2000 Jul;21(7):1037-45. doi: 10.1016/s0196-9781(00)00236-9.
The first reported behavioral action of the endogenous ligand for the "orphan" opioid receptor was a seemingly paradoxical increased sensitivity to nociception (i.e. hyperalgesia) after supraspinal injection into the cerebral ventricles of mice. In the continuing absence of an appropriate in vivo receptor antagonist, studies attempting to define the role of orphanin FQ/nociceptin (OFQ/N) in pain modulation and other behaviors have also featured central injection of peptide. This article reviews the findings of such studies. There appears to be concordance around the observation of anti-opioid actions of supraspinally injected OFQ/N, whereas the observations of hyperalgesia and/or analgesia are much less clear. A portion of the discrepant data may be explained in terms of methodological issues, stress-induced analgesia accompanying experimental protocols, and genotypic variation among subjects. Clarification of OFQ/N's role in nociception, as with other putative biologic functions, will probably depend upon the availability of a selective receptor antagonist.
“孤儿”阿片受体的内源性配体首次报道的行为作用是，在向小鼠脑室进行脊髓上注射后，对伤害感受的敏感性出现了看似矛盾的增加（即痛觉过敏）。在仍然缺乏合适的体内受体拮抗剂的情况下，试图确定孤啡肽/痛敏肽（OFQ/N）在疼痛调节及其他行为中作用的研究，也都采用了向中枢注射该肽的方法。本文综述了此类研究的结果。对于脊髓上注射OFQ/N的抗阿片样作用的观察结果似乎较为一致，而关于痛觉过敏和/或镇痛的观察结果则不太明确。部分存在差异的数据或许可以从方法学问题、实验方案伴随的应激诱导镇痛以及实验对象的基因变异等方面来解释。与其他假定的生物学功能一样，要阐明OFQ/N在伤害感受中的作用，可能取决于选择性受体拮抗剂的可得性。
