中文摘要：

目的研究鞘内注射吗啡对大鼠中脑导水管周围灰质（PAG）、海马和脊髓μ阿片受体（MOR）mRNA表达的影响,探讨大鼠鞘内注射吗啡免疫功能抑制的机制。方法清洁级成年雄性SD大鼠,鞘内置管成功的16只大鼠随机分为2组（n=8）：生理盐水组（NS组）和吗啡组（M组）。M组鞘内持续输注吗啡10μg/h 7 d（生理盐水稀释）,NS组给予等体积的生理盐水。输注7 d后断头处死大鼠,取出大鼠PAG、海马和脊髓标本,采用巢式RT-PCR测定MOR mRNA的表达。结果与NS组比较,M组PAG和海马MOR mRNA表达下调（P〈0.05或0.01）,脊髓MOR mRNA表达无统计学意义（P〉0.05）。结论大鼠PAG和海马MOR表达下调可能是鞘内注射吗啡导致免疫功能抑制的机制之一。

英文摘要：

　Objective To investigate the effect of intrathecal（IT）morphine on mu opioid receptor mRNA expression in periaqueductal gray matter（PAG）,hippocampus and spinal cord and the mechanism of immune depression induced by IT morphine.Methods Sixteen male SD rats weighing 260-320 g were randomly divided into 2 groups（n=8 each）：control group and morphine group.A micro-catheter was inserted into the subarachnoid space in the lumbar region according to the method described by Yaksh.Five days later morphine was infused IT at 10μg/h for 7 days using Alzet pump in morphine group,while in control group normal saline was infused instead of morphine.The animals were decapitated and the brains and spinal cords were removed immediately and kept in liquid nitrogen.The mu opioid receptor mRNA expression was determined by RT-PCR. Results The mu opioid receptor mRNA expression in PAG and hippecampus was significantly down-regulated in morphine group as compared with control group.There was no significant difference in mu opioid receptor mRNA expression in the spinal cord between the 2 groups.Conclusion The down-regulation of mu opioid receptor mRNA in PAG and hippocampus may be one of the mechanisms of immune depression induced by IT morphine.