大鼠相关脑区p—CREB和c—Fos在吗啡点燃条件性位置偏爱条件下的变化

目的：研究磷酸化cAMP反应元件结合蛋白（phospho—cAMP response element binding protein,p-CREB）和c-Fos在吗啡点燃条件性位置偏爱激活大鼠海马、杏仁核表达的变化。方法：以剂量递增连续皮下（s．c．）注射吗啡6d建立吗啡诱导大鼠条件位置性偏爱（conditionedplacepreference,CPP）模型,第7天用生理盐水替代吗啡训练大鼠10d,使CPP消退,单次s．c．吗啡（4mg／kg）激发已消退的CPP。采用免疫组化技术测定吗啡激发CPP重现时大鼠海马、杏仁核p-CREB和c—Fos的变化。结果：吗啡可使大鼠产生CPP效应,吗啡4mg／kg可使已消失的CPP效应激活;吗啡诱发CPP激活时大鼠海马、杏仁核p-CREB和c—Fos的表达增加。结论：海马、杏仁核p-CREB和c—Fos蛋白的表达参与了吗啡点燃CPP重现。     

东茛菪碱对吗啡依赖大鼠条件位置性偏爱激活的抑制作用

目的：观察东莨菪碱（Scopolamine，Sco）对吗啡（Morphine，Mor）依赖大鼠条件位置性偏爱激活的抑制作用。方法：以剂量递增连续皮下（SC）给吗啡6天建立吗啡诱导大鼠条件位置性偏爱（CPP）模型，第7天用生理盐水替代吗啡训练大鼠10天，使形成的CPP逐渐消退，单次SC4mg／kg吗啡激发消退的CPP。部分大鼠在注射吗啡前30分钟分别腹腔注射（ip）Sco（1mg／kg、2mg／kg、3mg／kg）。观察东莨菪碱对吗啡依赖大鼠在伴药箱停留时间的变化。结果：与Mor依赖组相比在SC4mg／kgMor引燃刺激前30min应用Sco 1mg／kg、2mg／kg、3mg／kg均可以使大鼠在伴药箱停留时间缩短（P〈0．05）。结论：Sco一定程度上抑制Mor引燃的Mor依赖大鼠的条件位置性偏爱激活。     

褪黑素抗大鼠吗啡奖赏效应的表达与脑内CREB及其磷酸化

目的:观察褪黑素(melatonin,Mel)对大鼠吗啡诱导的条件性位置偏爱(CPP)效应表达的影响及此过程中脑内cAMP反应元件结合蛋白(CREB)及其磷酸化的变化。方法:(1)大鼠连续6 d给予吗啡(sc,5 mg.kg-1/d)建立CPP模型,于CPP测试前20 min ip Mel(50和25 mg.kg-1),观察Mel对大鼠吗啡诱导的CPP效应表达的影响。(2)大鼠同上建立吗啡CPP模型,d7上、下午,d8上午ip Mel 50 mg.kg-1,共3次,最后一次ip后6 h,采用免疫组化结合计算机图像处理技术测定脑内伏隔核、海马内CREB及磷酸化CREB(p-CREB)的免疫阳性反应强度。结果:Mel 50 mg.kg-1可显著翻转大鼠吗啡诱导的CPP评分升高(P<0.01),同时显著降低吗啡诱导的大鼠伏隔核、海马内p-CREB的上调(P<0.01)。结论:Mel抑制大鼠吗啡奖赏效应的表达,此作用可能与其抑制吗啡诱导的伏隔核、海马内p-CREB蛋白水平上调有关。     

吗啡依赖和复吸时大鼠脑内神经甾体水平的变化

目的探讨吗啡精神依赖和复吸对大鼠脑内神经甾体水平的影响。方法采用条件性位置偏爱(CPP)实验,吗啡诱导大鼠CPP形成,足底电击应激诱发CPP重建,高效液相色谱-质谱法测定大鼠额叶皮质、海马及血浆中孕烯醇酮(PREG)及其硫酸酯(PREGS)、别孕烯醇酮(AP)、脱氢表雄酮(DHEA)及其硫酸酯(DHEAS)的含量。结果5 mg.kg-1吗啡训练10 d诱导大鼠产生了稳定的CPP,间歇足底电击有效诱发CPP的重建。与对照组比较,吗啡CPP形成时,大鼠额叶皮质内DHEA、PREG水平升高(P<0.05),海马内DHEA水平降低(P<0.05);与吗啡消退组比较,足底电击诱发CPP重现时,大鼠额叶皮质内PREG水平降低(P<0.01),而海马内PREG水平升高(P<0.05)。结论大鼠额叶皮质和海马内神经甾体水平的变化可能与吗啡依赖和复吸有关。     

东莨菪碱对吗啡依赖大鼠条件位置性偏爱激活的抑制作用

目的:观察东莨菪碱(Scopolamine,Sco)对吗啡(Morphine,Mor)依赖大鼠条件位置性偏爱激活的抑制作用。方法:以剂量递增连续皮下(SC)给吗啡6天建立吗啡诱导大鼠条件位置性偏爱(CPP)模型,第7天用生理盐水替代吗啡训练大鼠10天,使形成的CPP逐渐消退,单次SC4mg/kg吗啡激发消退的CPP。部分大鼠在注射吗啡前30分钟分别腹腔注射(ip)Sco(1mg/kg、2mg/kg、3mg/kg)。观察东莨菪碱对吗啡依赖大鼠在伴药箱停留时间的变化。结果:与Mor依赖组相比在SC4mg/kgMor引燃刺激前30min应用Sco1mg/kg、2mg/kg、3mg/kg均可以使大鼠在伴药箱停留时间缩短(P<0.05)。结论:Sco一定程度上抑制Mor引燃的Mor依赖大鼠的条件位置性偏爱激活。     

虎门合剂对吗啡诱导的大鼠条件性位置偏爱效应及伏核内BDNF蛋白表达的影响

目的:研究虎门合剂对吗啡诱导的大鼠条件性位置偏爱(CPP)效应及伏核内BDNF表达水平的调节作用。方法:使用盐酸吗啡建立大鼠CPP模型,采用Obersiver5.0行为学软件分析大鼠的CPP效应:使用高中低剂量虎门合剂干预CPP形成;利用Western blot方法测定伏核内BDNF的蛋白含量。结果:吗啡模型组大鼠在伴药箱中停留的时间较正常对照组明显延长(P<0.001),同时伏核中的BDNF蛋白表达水平亦显著升高(P<0.001)。而虎门合剂中高剂量干预组大鼠较吗啡模型组在伴药箱中停留的时间和伏核内BDNF含量则显著下降(P<0.01)。结论:中高剂量虎门合剂能显著抑制吗啡诱导的CPP效应,其作用机制与降低伏核内BDNF蛋白表达水平有关。     

咖啡因对大鼠吗啡条件性位置偏爱获得和重现的影响

目的:本文以大鼠条件性位置偏爱(CPP)为模型,探讨咖啡因对阿片类物质奖赏效应的影响。方法:30只大鼠分为四组:吗啡组、吗啡+咖啡因组、咖啡因组和生理盐水对照组。前三组大鼠隔日分别皮下注射(sc)吗啡(5mg·kg-1)、吗啡+咖啡因(5mg·kg-1+5mg·kg-1)、咖啡因(5mg·kg-1)和生理盐水进行CPP训练。生理盐水组大鼠一直给予等体积的生理盐水。CPP建立后,比较CPP效应强度。待各组大鼠CPP消退后,均sc咖啡因(5mg.kg-1)观察CPP重现情况。结果:吗啡组、吗啡+咖啡因组、咖啡因组大鼠均形成了CPP。吗啡+咖啡因组大鼠CPP强度最高,但与吗啡组、咖啡因组比较差异无显著性。单次sc咖啡因可使咖啡因+吗啡组CPP重现,但没有使吗啡组和咖啡因组大鼠CPP重现。结论:咖啡因与吗啡的奖赏作用可能具有相加或协同作用;单剂量咖啡因给药可使吗啡和咖啡因的混合物形成的CPP重现;实验结果提示阿片类物质中掺杂咖啡因不但是成瘾形成的危险因素,也可能是诱导复吸的危险因素。     

应激损害吗啡奖赏记忆再巩固及其对海马CA1脑区活性调节细胞骨架蛋白（Arc）表达的影响

目的：观察应激是否损害吗啡奖赏记忆再巩固及其对海马活性调节细胞骨架蛋白（Arc）的影响。方法：（1）建立大鼠吗啡条件位置偏爱（conditioned place preference,CPP）模型,给予不同的处理即暴露、应激、暴露后立即应激,观察应激对吗啡奖赏记忆再巩固的作用。（2）建立吗啡CPP模型,暴露6 h后应激,观察应激损害吗啡奖赏记忆再巩固是否存在时间窗。（3）处理测试后的大鼠断头取脑,采用免疫荧光法和Western blot法分析应激对吗啡CPP大鼠海马Arc表达的影响。结果：（1）吗啡奖赏记忆唤起后立即给予应激,其再巩固受到损害（P〈0.05）。（2）应激损害吗啡奖赏记忆再巩固作用存在时间窗（P〈0.05）。（3）暴露后给予应激组大鼠在CPP测试后海马CA1脑区中的Arc表达下降（P〈0.05）。结论：（1）应激可损害吗啡奖赏记忆再巩固,且其作用具有时间窗。（2）应激损害吗啡记忆再巩固可能与其降低海马CA1脑区的Arc表达有关。     

氯胺酮诱导的大鼠条件性位置偏爱

目的:探讨氯胺酮在大鼠模型上形成条件性位置偏爱(CPP)的特点,分析氯胺酮精神依赖性潜力。方法:(1)60只SD♂大鼠随机分为对照组、氯胺酮及吗啡阳性对照组。(2)氯胺酮组每隔24h腹腔注射氯胺酮10m·lkg-1一次,连续6d,建立大鼠氯胺酮精神依赖性模型,吗啡组给予等剂量的吗啡,对照组则给予等剂量的生理盐水;(3)氯胺酮组及吗啡组于CPP形成后给予生理盐水进行消退实验。结果:(1)氯胺酮组及吗啡组大鼠出现了明显的CPP;(2)与吗啡组相比,氯胺酮组的CPP效应更显著,但消退较快。结论:氯胺酮可诱导大鼠产生CPP,但随着时间的推移CPP消退速度较吗啡快。     

下边缘皮质中神经元周围基质网络（PNNs）的降解联合消退训练能够抑制吗啡奖赏记忆的复燃

目的：利用硫酸软骨素酶（ChABC）降解下边缘皮质神经元周围基质网络（PNNs）之后,观察对于吗啡奖赏记忆复燃的影响。方法：采用条件性位置偏爱（CPP）模型,用核团微注射方法。结果：（1）与PBS对照组相比,消退训练前在下边缘皮质微注射ChABC将PNNs降解之后联合消退训练能够抑制消退后低剂量吗啡引起的CPP复燃;（2）与对照组相比,吗啡CPP训练前下边缘皮质微注射ChABC,对于吗啡CPP的获得没有影响。结论：本研究发现下边缘皮质神经元周围基质网络（PNNs）/硫酸软骨素蛋白聚糖（CSPGs）降解之后,可以抑制消退后低剂量药物引起的觅药行为的复现。这种作用可能是通过PNNs/CSPGs降解能够增强吗啡奖赏消退记忆来发挥作用的。     

Effects of scopolamine and ketamine on reconsolidation of morphine conditioned place preference in rats

Persistent memory associated with addictive drugs contributes to the relapse of drug abuse. The current study was conducted to examine the effects of scopolamine and ketamine on reconsolidation of morphine-induced conditioned place preference (CPP). In experiment 1, after morphine CPP was acquired, rats were injected with ketamine (60 mg/kg, intraperitoneally) and scopolamine (2 mg/kg, intraperitoneally), respectively, after reexposure to an earlier morphine-paired context or in their home cages. The CPP was reassessed 24 and 48 h after reexposure. An additional group of rats received saline following reexposure to the earlier morphine-paired context. In experiment 2, two groups of rats were only given saline during the CPP training and subsequent administration of ketamine or scopolamine during the reexposure. In experiment 1, rats failed to exhibit morphine CPP when ketamine and scopolamine were administered only after reexposure to a morphine-paired context. CPP was not abolished by ketamine or scopolamine administration in the animals' home cages. Also, the animals receiving only saline injections showed strong morphine CPP 24 h after a short exposure to the morphine-paired context. In experiment 2, ketamine or scopolamine treatment alone did not induce CPP or aversion. Administration of scopolamine and ketamine, after reexposure to a drug-paired context, resulted in the disruption of morphine CPP, suggesting the potential effects of scopolamine and ketamine in disrupting memory associated with environmental cues and addictive drugs.     

Reactivation of morphine conditioned place preference by drug priming: role of environmental cues and sensitization

RATIONALE: Relapse is a major characteristic of drug addiction and remains the primary problem in treating drug abuse. Despite a great deal of research, the exact factors that determine renewed drug-seeking and persistent craving for them remain unclear. OBJECTIVE: The present study was designed to evaluate the role of environmental cues and behavioral sensitization in reactivation of place preference following long-term extinction of morphine conditioned place preference (CPP) in rats. METHODS: After being injected with morphine and saline alternately for 6 days to induce morphine CPP, the rats were subjected to extinction of conditioning for 21 days. The rats were then administered various doses of morphine, heroin, or cocaine and confined in the previous drug- or saline-paired compartment. CPP was determined. Some rats were treated with scopolamine or naloxone prior to administration of these three drugs. RESULTS: Morphine CPP disappeared following a 21-day extinction. A single injection of morphine, heroin, or cocaine evoked place preference for the previous drug-paired side. However, place preference for the previous vehicle-paired side was induced after the animals received a single injection of morphine, heroin or cocaine and confined to the previous vehicle-paired compartment. Administration of naloxone prior to drug treatment significantly attenuated the place preference induced by morphine or heroin, but had no significant effect on the place preference elicited by cocaine. Administration of the cholinergic antagonist scopolamine before morphine, heroin and cocaine inhibited the expression of place preference. CONCLUSIONS: Environment-related cues and behavioral sensitization play critical roles in the incentive motivation underlying drug-seeking behaviors.     

褪黑素对吗啡依赖大鼠复吸行为的抑制作用

目的 :研究褪黑素对吗啡依赖大鼠复吸行为的抑制作用。方法 :以剂量递增法连续皮下注射 (sc)吗啡 6d建立吗啡诱导的大鼠条件性位置偏爱 (CPP)模型 ,d7用生理盐水替代吗啡训练大鼠 10d ,以使形成的CPP逐渐消退。单次sc 4mg·kg- 1 吗啡以唤起消退的CPP的恢复。部分大鼠在注射吗啡前 30min分别腹腔注射 (ip)褪黑素 2 0、4 0和 80mg·kg- 1 进行治疗。结果 :与吗啡依赖组相比 ,在sc 4mg·kg- 1 吗啡引燃刺激前 30min应用褪黑素 4 0和 80mg·kg- 1 急性治疗 ,可以使大鼠在伴药箱的停留时间明显缩短 ,(P <0 0 5、P <0 0 1) ;而褪黑素 2 0mg·kg- 1 急性治疗亦使大鼠在伴药箱的停留时间缩短 ,但无统计学意义 ,P >0 0 5。结论 :褪黑素在一定程度上可以抑制吗啡引燃的吗啡依赖大鼠的复吸行为     

The effect of L-stepholidine, a novel extract of Chinese herb, on the acquisition, expression, maintenance, and re-acquisition of morphine conditioned place preference in rats

The effect of L-stepholidine (SPD), a novel alkaloid extract of the Chinese herb Stephania with partial dopamine D1 receptor agonistic and D2 receptor antagonistic dual actions, on morphine conditioned place preference (CPP) was studied. Daily injection of morphine (10 mg/kg, i.p.) for 6 days induced CPP in rats, and daily treatment with SPD at 10 or 20 mg/kg before morphine injection dose-dependently attenuated morphine-induced CPP. On the day following acquisition of morphine CPP, a single administration of SPD at 10 or 20 mg/kg failed to block the expression of CPP. However, daily administration of SPD at 20 mg/kg for 7 days attenuated the maintenance of CPP. Morphine-induced CPP extinguished after a 21-day saline training and then a single injection of morphine (3 mg/kg, i.p.) induced re-acquisition of morphine CPP; however, pretreatment with SPD at 10 or 20 mg/kg 30 min before morphine injection dose-dependently blocked morphine (3 mg/kg, i.p.)-induced re-acquisition of morphine CPP. Furthermore, our data indicate that SPD had no effect on food-induced CPP or state-dependent learning, suggesting that the observed effect of SPD does not result from an inhibition of general learning ability. These results demonstrate that SPD can inhibit acquisition, maintenance, and re-acquisition of morphine conditioned place preference and suggest its potential for treatment of opioid addiction.     

Effects of beta-funaltrexamine and naloxonazine on single-trial morphine-conditioned place preference and locomotor activity

The current study assessed the ability of the selective irreversible mu-opioid receptor antagonists beta-funaltrexamine (betaFNA) and naloxonazine (NALZ) to alter the locomotor and rewarding effects of a single intravenous injection of morphine using the conditioned place preference (CPP) model. In the first experiment, rats were conditioned with a single injection of morphine (10 mg/kg iv) paired with one compartment of a CPP apparatus and then were tested for CPP at either 1 or 7 days after conditioning. Rats showed hypoactivity following acute morphine on the conditioning trial and showed CPP when tested either 1 or 7 days later. In the next experiments, rats were pretreated with betaFNA (20 mg/kg sc, 20 h before conditioning), NALZ (15 or 30 mg/kg sc, 24 h before conditioning) or saline and then were conditioned with a single injection of morphine (10 mg/kg iv) or saline. Pretreatment with NALZ alone, but not betaFNA, significantly decreased locomotor activity; neither antagonist alone produced a significant shift in preference for either compartment of the CPP apparatus. Pretreatment with either betaFNA or NALZ blocked completely morphine-induced hypoactivity, but neither antagonist had a significant effect on morphine CPP. These results indicate that mu-opioid receptors are more critically involved in acute morphine-induced hypoactivity than in acute morphine reward.     

左旋四氢巴马汀对吗啡条件性位置偏爱的影响

目的探讨不同剂量的左旋四氢巴马汀(lTetrahydropalmatine,lTHP)对吗啡诱导的条件性位置偏爱(CPP)的影响以及自身能否产生CPP效应。方法本实验采用倾向性实验程序,①对♂SD大鼠sc吗啡(5.00mg·kg-1)或生理盐水(NS)训练8d,d9测定大鼠对伴药侧的偏爱效应或测试前40minipNS或不同剂量的lTHP(1.25～5.00mg·kg-1),观察这些预处理对该效应的影响;②测量不同剂量的lTHP(1.25～5.00mg·kg-1)慢性用药(每天1次,ip)对CPP效应消退的影响;③测试ipNS或lTHP(1.25～5.00mg·kg-1)能否诱导大鼠对伴药侧产生偏爱(方法同吗啡)。结果5.00mg·kg-1吗啡诱导大鼠对伴药盒产生明显的CPP;测试前ip2.50mg·kg-1或5.00mg·kg-1的lTHP明显降低吗啡诱导的CPP效应的表达(P<0.05),其慢性给药明显加速吗啡CPP效应的消退;3个剂量的lTHP均不能诱导大鼠形成CPP。结论lTHP能抑制吗啡的奖赏效应,可在吗啡成瘾的治疗中发挥一定的作用。     

Scopolamine inhibits cocaine-conditioned but not unconditioned stimulant effects in mice

RATIONALE: In animal models, cocaine cues contribute to the development of conditioned responses to the psychomotor stimulating and rewarding effects of the drug. OBJECTIVES: In the present study we investigated the effect of scopolamine, known to impair learning and memory, on cocaine-induced conditioned and unconditioned responses in Swiss Webster mice. METHODS: In the first experiment, mice were treated with saline/saline, saline/cocaine (20 mg/kg), scopolamine (1.0 mg/kg)/cocaine, or scopolamine/saline for 5 days. The treatments were paired with the locomotor activity test cage twice, on days 1 and 5. This allowed to determine: (a) the induction and expression of place-dependent sensitization (PDS) to the psychomotor-stimulating effect of cocaine and (b) place-dependent hyperlocomotion (PDH; i.e., conditioning) as defined by the response to saline injection in the test cage. In the second experiment, all injections were delivered in animals' home cage in order to induce place-independent sensitization (PIS) to cocaine and to avoid the development of PDH. In the third experiment, the effect of scopolamine (1.0 mg/kg) on the acquisition of cocaine-induced conditioned place preference (CPP) was investigated. RESULTS: Data from the first experiment suggest that pretreatment with scopolamine had no specific effect on the induction and expression of cocaine-induced PIS. However, scopolamine blocked cocaine-induced PDH. Results from the second experiment confirmed that scopolamine had no effect on the induction of PIS to cocaine. Results from the third experiment showed that scopolamine completely blocked cocaine-induced CPP. CONCLUSIONS: The finding that scopolamine blocked the conditioned behaviors, PDH and CPP, that develop after exposure to cocaine supports the hypothesis that cocaine cue reactivity in the paradigms tested is associated with learning and memory.