腹外侧眶皮层内给予吗啡对福尔马林试验诱发脊髓背角c-fos表达的抑制效应

目的　研究前额叶腹外侧眶皮层 (VLO)内微量注射吗啡对大鼠福尔马林试验诱发的腰段脊髓背角c fos蛋白表达的抑制作用。方法　用免疫组化的方法观察c fos样免疫反应神经元在脊髓背角的表达。结果　VLO内微量注射吗啡明显抑制大鼠后爪注射福尔马林诱发的脊髓背角c fos蛋白表达 ,c fos阳性神经元数为 1 8.5 0± 0 .2 6,与注射生理盐水 5 8.2 5± 0 .98相比 ,差异显著(P <0 .0 0 1 ) ,并且这种抑制效应可被VLO内注射阿片受体拮抗剂纳络酮所翻转 ,其c fos阳性神经元数为 5 6.32± 2 .2 8,与单独注射吗啡相比差异显著 (P <0 .0 0 1 ) ,但与注射生理盐水相比 ,无显著差异 (P >0 .0 5 )。结论　阿片肽及其受体可能参与VLO介导的下行抗伤害感受效应

Inhibitory effect of morphine microinjection into the ventrolateral orbital cortex on c-fos expression of neurons in spinal dorsal horn induced by formalin-test in rats∥Huang Xin, Tang Jingshi, Yuan Bin, et al

Objective To investigate the possible inhibitory effect of microinjection of morphine into the ventrolateral orbital cortex (VLO) on the c fos expression of neurons in the spinal dorsal horn induced by formalin injection into the rat hindpaw. Methods The c fos expression was examined by immunohistochemical method.Results Microinjection of morphine (0.5?μg) into the VLO depressed the c fos expression of neurons in the spinal dorsal horn induced by formalin test with a statistically significant difference ( P < 0.001 ) as compared with that obtained from saline injection into VLO, and this effect could be antagonized by application of the opioid receptor antagonist naloxone (1.5?μg) into the same VLO site. The statistical difference was significant as compared with that of injection of morphine alone ( P < 0.001 ).Conclusion Opioid peptides and receptors may be involved in the descending antinociception mediated by VLO.