拮抗触液核P物质对吗啡戒断大鼠行为学的影响

目的观察P物质(substance P,SP)在吗啡戒断大鼠触液核内的表达及拮抗触液核内SP对吗啡戒断行为学的影响,探讨触液核内SP在吗啡戒断中的作用。方法 SPF级SD♂大鼠2组,吗啡戒断-人工脑脊液组(A组)和吗啡戒断-SP抑制剂组(B组);两组均采用剂量递增法腹腔注射盐酸吗啡,建立大鼠吗啡依赖模型,在d4上午侧脑室注射霍乱毒素亚单位B-辣根过氧化物酶复合物(CB-HRP)逆行追踪触液神经元;B组d5上午在立体定位仪下侧脑室注射SP拮抗剂(D-Pro2、D-Phe7、D-Trp9)-SP,A组注射人工脑脊液作为对照组;d6上午腹腔注射纳络酮(5mg·kg-1)建立吗啡戒断模型;并进行戒断行为学评分、记录戒断总评分(total withdrawal scores,TWS),免疫荧光结合激光共聚焦显微镜观察SP的表达。结果 A组大鼠触液核内SP表达增加,B组显示,拮抗触液核内SP可减弱吗啡戒断样症状;两组TWS相比较,A组高于B组(P<0.01)。结论抑制触液核内SP能够减轻吗啡戒断症状,本研究首次证实触液核SP表达参与了吗啡躯体依赖的发展与纳洛酮药物催促戒断,这将有助于利用药理学手段干预阿片依赖寻找新方法。

Effects of substance P antagonist on morphine withdrawal behavior in cerebrospinal fluid-contacting nucleus of rats

Aim To observe the effect of substance P(SP) in cerebrospinal fluid-contacting nucleus(CSFCN) of morphine withdrawal rats,and to study the relationship between morphine withdrawal and CSF-CN in rat brain parenchyma.Methods Male Sprague-Dawley rats(270～290 g) were randomly assigned into two groups.All the animals were intraperitoneally injected three times daily to set the model of morphine dependence.At day 4,all the animals were injected into one of the rats’lateral ventricles with the 30%CB-HRP. At day 5,group B were intracerebroventricular injected into the CSF-CN with the inhibitor of SP,(D-Pro2,DPhe7,D-Trp9) -SP,group A with the identical artificial cerebrospinal fluid(ACSF) .To test the morphine withdrawal-like behavioral signs,rats were placed in a plexiglass observation chamber to allow for acclimatization to the environment at day 6.Two hours later morphine withdrawal rats were injected with naloxone(5 mg· kg -1,sc) ,and withdrawal symptoms were monitored for an hour after naloxone administration.A dual-labeled immunofluorescent technique and laser scanning confocal microscopy were used to identify the expression of CB-HRP,SP and CB-HRP/SP in CSF-CN for each group.Results SP-expression in CSF-CN was significantly increased after naloxone injection.The withdrawal symptoms(TWS) of group B were significantly attenuated than group A.Conclusion The inhibited SP in CSF-CN can attenuate the morphine withdrawal signs.This study provides the first evidence that SPexpression in CSF-CN participate in the development of morphine physical dependence and naloxone precipitated withdrawal,which may provide a novel pharmacological therapeutic approach for preventing or reversing opioid dependence via icv injection.