孤啡肽在大鼠脑内对抗吗啡镇痛

脑内全新的阿片受体样受体（１９９４）及其内源性配体孤啡肽（１９９５）的发现形成了中枢神经系统阿片／抗阿片相互关系的研究领域中一个新的推动力。基于它们与阿片家族的高同源性及在脑内痛觉整合相关区域的丰富表达，本实验观察了ＯＦＱ在大鼠脑内对吗啡镇痛作用的影响。结果表明：（１）ＯＦＱ可以对抗脑室注射生理盐水引起的镇痛，后者可能是一种由内源性阿片系统介导的应激镇痛。（２）脑室注射ＯＦＱ在很大的剂量范围（４０

ANTAGONISTIC EFFECT OF ORPHANIN FQ ON MORPHINE ANALGESIA IN RAT BRAIN

The discovery of a novel receptor-opioid receptor-like (ORL) receptor (1994 ) andits endogenous ligand-Orphanin FQ (OFQ) (1995) represented a new approach in thestudy of opioids and anti-opioids in CNS. Based on the high homology of ORL receptorand OFQ with their opioid family counterparts, as well as the high expression of ORLreceptor mRNA and protein in the brain areas associated with nociception, the effect ofOFQ on morphine induced analgesia in the rat brain was further investigated. The results showed that: (1) Intracerebroventricular (i. c. v. ) injection of OFQ reversed thestress analgesia induced by i. c. v. injection of normal saline, which seems to be mediated by endogenous opioid peptides. (2) I. c. v. injection of OFQ dose-dependently antagonized morphine-induced analgesia dose-dependently. (3) I. c. v. injection of antisenseoligodeoxynucleotide for the gene encoding ORL receptor to block the expression ofORL receptor in the CNS potentiated the analgesia induced by cumulative injection ofmorphine. The results suggest that OFQ seems to play a role of anti-opioid peptide inthe rat brain.