大鼠海马CA2区GDNF mRNA表达与吗啡依赖和吗啡的关系

【目的】观察吗啡戒断大鼠侧脑室胶质细胞源性神经营养因子(GDNF)反义寡脱氧核苷酸注射后对海马GDNF mRNA表达的影响。【方法】SD大鼠侧脑室立体定位,皮下注射吗啡建立吗啡依赖大鼠模型,侧脑室微注射GDNF有义和反义寡脱氧核苷酸,纳洛酮催促戒断,应用原位杂交方法检测海马GDNF mRNA的表达。【结果】侧脑室注射GDNF反义寡脱氧核苷酸能显著抑制大鼠吗啡戒断症状评分(P<0.05)。吗啡依赖大鼠海马CA2区GDNF mRNA表达较对照组显著增加(P<0.05),CA1和CA3区变化不明显;吗啡依赖大鼠纳洛酮(4mg/kg,ip)催促戒断后海马CA1、CA2和CA3区GDNF mRNA表达较依赖组有增加趋势,但均没有显著差异(P>0.05);吗啡依赖大鼠纳洛酮激发前24h侧脑室注射GDNF反义寡脱氧核苷酸能显著抑制吗啡依赖大鼠依赖和戒断后CA2区GDNF mRNA表达的增加(P<0.05),而CA1和CA3区与戒断组大鼠相应区域相比没有差异;吗啡依赖大鼠纳洛酮激发前24h侧脑室注射GDNF有义寡脱氧核苷酸与戒断组大鼠相比海马CA1、CA2和CA3区GDNF mRNA表达均没有显著性差异(P>0.05)。【结论】在转录水平,海马CA2区GDNF表达的变化在吗啡依赖和戒断中可能起重要作用。     

肿瘤坏死因子α在吗啡依赖和戒断大鼠海马Cal区的表达变化

目的探讨吗啡依赖和戒断大鼠海马CA1区肿瘤坏死因子α的表达变化.方法实验于2004-04/2005-03在泸州医学院组织胚胎学实验室完成.实验动物选择普通级两三月龄雄性SD大鼠24只.按随机数字法将实验动物分为4组对照组、吗啡依赖组和盐酸纳洛酮催促戒断1 h组和戒断3 h组(后两组合称戒断组),每组6只.采用剂量递增法建立吗啡依赖动物模型,用纳洛酮催促吗啡依赖动物戒断反应.具体方法为每天两次在大鼠背部皮下注射盐酸吗啡,首日10 mg/kg,隔日每次增加10 mg/kg,至第6天末次注射50 mg/kg.吗啡依赖组末次注射后6 h麻醉下灌注固定.盐酸纳洛酮催促戒断组大鼠于末次注射吗啡6 h后,以盐酸纳洛酮5 mg/kg皮下注射激发戒断症状,1 h.和3 h后,同吗啡依赖组处理实验动物.对照组大鼠按照同期平行对照的原则,以相同方式注射同体积的生理盐水.记录大鼠在正常及实验状态下的活动状况.同时取大鼠海马CA1区分别作苏木精-伊红和肿瘤坏死因子α免疫组织化学,测免疫反应阳性细胞的数量和吸光度.结果整个实验过程未出现大鼠异常死亡,吗啡注射的所有动物均成功建立吗啡依赖动物模型,全部进入结果分析.①海马形态改变吗啡依赖和戒断大鼠海马CA1区出现结构松散、神经元萎缩和坏死等改变.②肿瘤坏死因子α蛋白表达对照组大鼠海马CA1区肿瘤坏死因子α蛋白表达轻度阳性,吗啡依赖组和戒断组肿瘤坏死因子α阳性细胞数均增加,各组阳性细胞主要是胶质细胞和神经元.各组阳性细胞均数与对照组比较,差异均有统计学意义[(34.83±3.54),(17.50±2.88),P＜0.01];[(38.83±4.62),(17.50±2.88),P＜0.01];[(58.17±6.62),(17.50±2.88),P＜0.01].而吗啡依赖组与盐酸纳洛酮催促戒断3 h组差异无统计学意义[(34.83±3.54),(38.83±4.62),P＞0.05].吗啡依赖组和戒断组肿瘤坏死因子α阳性细胞吸光度增加,各组阳性细胞吸光度均数与对照组比较差异也均有统计学意义[(0.378 0±0.009 4),(0.310 8±0.001 0),P＜0.01];[(0.399 9±0.012 0),(0.310 8±0.001 0),P＜0.01];[(0.385 5±0.006 6),(0.3108±0.001 0),P＜0.01],吗啡依赖组与盐酸纳洛酮催促戒断3 h组比较差异无统计学意义[(0.378 0±0.009 4),(0.385 5±0.006 6),P＞0.05].盐酸纳洛酮催促戒断1 h组与戒断3 h组肿瘤坏死因子α阳性细胞吸光度差异有显著性[(0.399 9±0.012 0),(0.385 5±0.006 6),P＜0.05].结论肿瘤坏死因子α参与了吗啡依赖和戒断的病理生理过程,可能是药物依赖形成中的脑损伤初始因素之一.     

肿瘤坏死因子α在吗啡依赖和戒断大鼠海马CA1区的表达变化

目的:探讨吗啡依赖和戒断大鼠海马CA1区肿瘤坏死因子α的表达变化。方法:实验于2004-04/2005-03在泸州医学院组织胚胎学实验室完成。实验动物选择普通级两三月龄雄性SD大鼠24只。按随机数字法将实验动物分为4组:对照组、吗啡依赖组和盐酸纳洛酮催促戒断1h组和戒断3h组(后两组合称戒断组),每组6只。采用剂量递增法建立吗啡依赖动物模型,用纳洛酮催促吗啡依赖动物戒断反应。具体方法为每天两次在大鼠背部皮下注射盐酸吗啡,首日10mg/kg,隔日每次增加10mg/kg,至第6天末次注射50mg/kg。吗啡依赖组末次注射后6h麻醉下灌注固定。盐酸纳洛酮催促戒断组大鼠于末次注射吗啡6h后,以盐酸纳洛酮5mg/kg皮下注射激发戒断症状,1h和3h后,同吗啡依赖组处理实验动物。对照组大鼠按照同期平行对照的原则,以相同方式注射同体积的生理盐水。记录大鼠在正常及实验状态下的活动状况。同时取大鼠海马CA1区分别作苏木精-伊红和肿瘤坏死因子α免疫组织化学,测免疫反应阳性细胞的数量和吸光度。结果:整个实验过程未出现大鼠异常死亡,吗啡注射的所有动物均成功建立吗啡依赖动物模型,全部进入结果分析。①海马形态改变:吗啡依赖和戒断大鼠海马CA1区出现结构松散、神经元萎缩和坏死等改变。②肿瘤坏死因子α蛋白表达:对照组大鼠海马CA1区肿瘤坏死因子α蛋白表达轻度阳性,吗啡依赖组和戒断组肿瘤坏死因子α阳性细胞数均增加,各组阳性细胞主要是胶质细胞和神经元。各组阳性细胞均数与对照组比较,差异均有统计学意义[(34.83±3.54),(17.50±2.88),P<0.01];[(38.83±4.62),(17.50±2.88),P<0.01];[(58.17±6.62),(17.50±2.88),P<0.01]。而吗啡依赖组与盐酸纳洛酮催促戒断3h组差异无统计学意义[(34.83±3.54),(38.83±4.62),P>0.05]。吗啡依赖组和戒断组肿瘤坏死因子α阳性细胞吸光度增加,各组阳性细胞吸光度均数与对照组比较差异也均有统计学意义[(0.3780±0.0094),(0.3108±0.0010),P<0.01];[(0.3999±0.0120),(0.3108±0.0010),P<0.01];[(0.3855±0.0066),(0.3108±0.0010),P<0.01],吗啡依赖组与盐酸纳洛酮催促戒断3h组比较差异无统计学意义[(0.3780±0.0094),(0.3855±0.0066),P>0.05]。盐酸纳洛酮催促戒断1h组与戒断3h组肿瘤坏死因子α阳性细胞吸光度差异有显著性[(0.3999±0.0120),(0.3855±0.0066),P<0.05]。结论:肿瘤坏死因子α参与了吗啡依赖和戒断的病理生理过程,可能是药物依赖形成中的脑损伤初始因素之一。     

噻萘普汀对吗啡处理大鼠内源性焦虑物质-苯甲二氮(艹卓)结合抑制因子mRNA表达的影响

目的:研究抗抑郁药噻萘普汀能否影响吗啡处理大鼠脑内内源性焦虑物质-苯甲二氮(艹卓)结合抑制因子(diazepam bindinginhibitor,DBI)mRNA的表达.方法:15只SD大鼠(四川大学动物实验中心提供),随机进入吗啡+生理盐水组、吗啡+噻萘普汀组和生理盐水组,每组5只.按照剂量递增每12 h给大鼠腹腔注射盐酸吗啡(10～80mg/kg,共10次),每次注射吗啡前0.5 h注射噻萘普汀(15 mg/kg),对照组给予同体积的生理盐水,各组于末次吗啡注射后2h,给与腹腔注射盐酸纳洛酮2mg/kg,促发戒断,2h后处死大鼠,提取脑内总RNA,进行RT-PCR,检测DBI mMRNA的表达.结果:吗啡+噻萘普汀组DBI mRNA表达(0.52±0.08)明显少于吗啡+生理盐水组(0.91±0.08),差异有显著性意义q=15.631 P＜0.01);与生理盐水组(0.40±0.06)差异无显著性意义(q=1.992,P＞0.05).结论:噻萘普汀能够影响吗啡处理大鼠脑内DBI mRNA的表达.     

噻萘普汀对吗啡处理大鼠内源性焦虑物质—苯甲二氮革结合抑制因子mRNA表达的影响

目的：研究抗抑郁药噻萘普汀能否影响吗啡处理大鼠脑内内源性焦虑物质一苯甲二氮草结合抑制因子(diazepam binding inhibitor,DBI)mRNA的表达。方法：15只SD大鼠(四川大学动物实验中心提供)，随机进入吗啡+生理盐水组、吗啡+噻萘普汀组和生理盐水组，每组5只。按照剂量递增每12h给大鼠腹腔注射盐酸吗啡(10～80mg／kg，共10次)，每次注射吗啡前0．5h注射噻萘普汀(15mg／kg)，对照组给予同体积的生理盐水，各组于末次吗啡注射后2h，给与腹腔注射盐酸纳洛酮2mg／kg，促发戒断。2h后处死大鼠，提取脑内总RNA，进行RT-PCR，检测DBI mMRNA的表达。结果：吗啡+噻萘普汀组DBI mRNA表达(0．52&;#177;0．08)明显少于吗啡+生理盐水组(0．91&;#177;0．08)，差异有显著性意义q=15．631P&;lt;0．01)；与生理盐水组(0．40&;#177;0．06)差异无显著性意义(q=1．992，P&;gt;0．05)。结论：噻萘普汀能够影响吗啡处理大鼠脑内DBI mRNA的表达。     

噻萘普汀对吗啡处理大鼠内源性焦虑物质—苯甲二氮结合抑制因子mRNA表达的影响

目的:研究抗抑郁药噻萘普汀能否影响吗啡处理大鼠脑内内源性焦虑物质-苯甲二氮结合抑制因子(diazepambindinginhibitor,DBI)mRNA的表达。方法:15只SD大鼠(四川大学动物实验中心提供),随机进入吗啡+生理盐水组、吗啡+噻萘普汀组和生理盐水组,每组5只。按照剂量递增每12h给大鼠腹腔注射盐酸吗啡(10～80mg/kg,共10次),每次注射吗啡前0.5h注射噻萘普汀(15mg/kg),对照组给予同体积的生理盐水,各组于末次吗啡注射后2h,给与腹腔注射盐酸纳洛酮2mg/kg,促发戒断,2h后处死大鼠,提取脑内总RNA,进行RT-PCR,检测DBImMRNA的表达。结果:吗啡+噻萘普汀组DBImRNA表达(0.52±0.08)明显少于吗啡+生理盐水组(0.91±0.08),差异有显著性意义q=15.631P<0.01);艹卓与生理盐水组(0.40±0.06)差异无显著性意义(q=1.992,P>0.05)。结论:噻萘普汀能够影响吗啡处理大鼠脑内DBImRNA的表达。     

吗啡依赖与戒断大鼠脑组织μ阿片受体的变化

目的用光学放射自显影术对吗啡依赖与戒断大鼠脑组织μ阿片受体进行定位和定量研究.方法30只SD大鼠随机分为吗啡依赖组、吗啡戒断组和生理盐水对照组,每组10只.依赖组和戒断组大鼠以腹腔注射吗啡的方法建立吗啡依赖模型,戒断组在依赖后腹腔注射纳洛酮5 mg/kg诱导戒断症状,对照组注射生理盐水.取大鼠不同脑区(包括额叶皮质、海马、纹状体、丘脑、下丘脑)进行光学放射自显影研究,分析大鼠依赖及戒断前后μ阿片受体数目及分布的改变.结果(1)依赖组大鼠与对照组大鼠相比,额叶皮质、海马、纹状体、丘脑、下丘脑的μ受体特异性结合密度发生非常显著下降(P＜0.01);(2)戒断组大鼠与吗啡依赖组比较,额叶皮质、丘脑、海马、纹状体、下丘脑的μ受体特异性结合密度发生了显著的上调(P＜0.05或0.01).但除下丘脑外(P＞0.05),其余脑区的μ受体特异性结合密度仍非常显著地低于正常水平(P＜0.01).结论实验结果表明大鼠不同脑区在吗啡依赖过程中μ阿片受体出现明显下调,予纳洛酮催促戒断,μ阿片受体较依赖组大鼠有显著回升,但仍显著低于正常组水平,这可能是阿片类依赖和戒断的重要神经生物学机制之一.     

肿瘤坏死因子α在吗啡依赖和戒断大鼠海马CA1区的表达变化

目的：探讨吗啡依赖和戒断大鼠海马CA1区肿瘤坏死因子α的表达变化。方法：实验于2004—04／2005—03在泸州医学院组织胚胎学实验室完成。实验动物选择普通级两三月龄雄性SD大鼠24只。按随机数字法将实验动物分为4组：对照组、吗啡依赖组和盐酸纳洛酮催促戒断1h组和戒断3h组（后两组合称戒断组），每组6只。采用剂量递增法建立吗啡依赖动物模型，用纳洛酮催促吗啡依赖动物戒断反应。具体方法为每天两次在大鼠背部皮下注射盐酸吗啡，首日10mg／kg，隔日每次增加10mg／kg，至第6天末次注射50mg／kg。吗啡依赖组末次注射后6h麻醉下灌注固定。盐酸纳洛酮催促戒断组大鼠于末次注射吗啡6h后，以盐酸纳洛酮5mg／kg皮下注射激发戒断症状，1h和3h后，同吗啡依赖组处理实验动物。对照组大鼠按照同期平行对照的原则，以相同方式注射同体积的生理盐水。记录大鼠在正常及实验状态下的活动状况。同时取大鼠海马CA1区分别作苏木精一伊红和肿瘤坏死因子α免疫组织化学，测免疫反应阳性细胞的数量和吸光度。结果：整个实验过程未出现大鼠异常死亡，吗啡注射的所有动物均成功建立吗啡依赖动物模型，全部进入结果分析。①海马形态改变：吗啡依赖和戒断大鼠海马CA1区出现结构松散、神经元萎缩和坏死等改变。②肿瘤坏死因子α蛋白表达：对照组大鼠海马CA1区肿瘤坏死因子α蛋白表达轻度阳性，吗啡依赖组和戒断组肿瘤坏死因子α阳性细胞数均增加，各组阳性细胞主要是胶质细胞和神经元。各组阳性细胞均数与对照组比较，差异均有统计学意义[（34．83&;#177;3.54），（17．50&;#177;2．88），P〈0．01]；[（38．83&;#177;4．62），（17．50&;#177;2．88），P〈0．01]；[（58．17&;#177;6．62），（17．50&;#177;2．88），P〈0．01]。而吗啡依赖组与盐酸纳洛酮催促戒断3h组差异无统计学意义[（34．83&;#177;3．54），（38．83&;#177;4．62），P〉0．05]。吗啡依赖组和戒断组肿瘤坏死因子α阳性细胞吸光度增加，各组阳性细胞吸光度均数与对照组比较差异也均有统计学意义[（0．3780&;#177;0．0094），（0．3108&;#177;0．0010），P〈0．01]；[（0.3999&;#177;0．0120）,（0．3108&;#177;0．0010），P〈0．01]；[（0．3855&;#177;0．0066），（0．3108&;#177;0．0010），P〈0．01]，吗啡依赖组与盐酸纳洛酮催促戒断3h组比较差异无统计学意义[（0．3780&;#177;0．0094），（0．3855&;#177;0．0066），P〉0．05]。盐酸纳洛酮催促戒断1h组与戒断3h组肿瘤坏死因子α阳性细胞吸光度差异有显著性[（0．3999&;#177;0．0120），（0．3855&;#177;0．0066），P〈0．05]。结论：肿瘤坏死因子α参与了吗啡依赖和戒断的病理生理过程，可能是药物依赖形成中的脑损伤初始因素之一。     

吗啡依赖与戒断大鼠脑组织μ阿片受体的变化

背景：内源性阿片肽-阿片受体系统的改变是阿片类药物成瘾的一个重要机制。在离体条件下，给予μ阿片受体拮抗剂或激动剂可以调节阿片受体水平。但不同的实验结果差别很大。目的：用光学放射自显影术对吗啡依赖与戒断大鼠脑组织μ阿片受体进行定位和定量研究。设计：完全随机分组实验研究。地点和对象：实验在第二军医大学长征医院麻醉科完成，对象为雄性SD大鼠30只，体质量180—220g，由第二军医大学动物实验中心提供。干预：30只SD大鼠随机分为吗啡依赖组、吗啡戒断组和生理盐水对照组，每组10只。依赖组和戒断组大鼠以腹腔注射吗啡的方法建立吗啡依赖模型，戒断组在成瘾后腹腔注射纳洛酮5mg／kg诱导戒断24h，对照组注射生理盐水。主要观察指标：大鼠不同脑区μ阿片受体特异性结合密度。结果：依赖组大鼠与对照组大鼠相比，额叶皮质、海马、纹状体、丘脑、下丘脑的μ受体特异性结合密度发生非常显著下降(t=11．54，17．82，15．80，8．35，13．78，P&;lt;0．01)，下降幅度分别为22％，49％，21％，28％，39％；戒断组大鼠与吗啡依赖组比较，额叶皮质、海马、纹状体、丘脑、下丘脑的μ受体特异性结合密度发生了显著的上调(t=3．72，7．77，5．84，3．06，11．24，P&;lt;0．01)，上调幅度分别为10％，38％，12％，13％，58％。但除下丘脑外(t=1．64，P&;gt;0．05)，其余脑区的μ受体特异性结合密度仍非常显著地低于正常水平(t=6．76，11．73，10．19，5．46，P&;lt;0．01)。结论：大鼠不同脑区在吗啡成瘾过程中μ阿片受体出现明显下调，予纳洛酮催促戒断，μ阿片受体较依赖组大鼠有显著回升，但仍显著低于正常组水平，这可能是阿片类依赖和戒断的重要神经生物学机制之一。     

胍丁胺对吗啡戒断大鼠海马神经元型一氧化氮合酶的影响

背景:胍丁胺具有增强吗啡的镇痛作用、对抗吗啡的耐受和依赖等作用。目的:观察注射胍丁胺对吗啡戒断大鼠海马神经元型一氧化氮合酶的影响,分析海马一氧化氮通路是否参与胍丁胺抑制吗啡的戒断作用。设计:随机对照实验。单位:解放军总医院麻醉科。材料:实验于2004-04/07在解放军总医院麻醉科实验室完成。选取健康SD大鼠18只,随机分为盐水对照组、吗啡组、胍丁胺吗啡组,6只/组。方法:盐水对照组皮下注射生理盐水10mg/kg;吗啡组进行5d预处理,分别皮下注射吗啡10,20,30,40,50mg/kg,2次/d;胍丁胺吗啡组每次给予吗啡前30min皮下注射胍丁胺10mg/kg。末次给吗啡后6h,吗啡组和胍丁胺吗啡组均腹腔注射纳洛酮5mg/kg,激发吗啡戒断症状,记录1h内各项吗啡戒断症状的次数(包括湿狗样抖动、咀嚼、激惹、流涎、腹泻等体征),根据动物在纳洛酮激发戒断症状的前后体重差值计算体质量减轻数。行为学测定后将各组动物麻醉处死,取海马作冰冻切片,神经元型一氧化氮合酶免疫组织化学染色。用CMIAS系统进行图像分析,每张切片选5个视野积分吸光度的均值作为阳性神经元的积分吸光度。主要观察指标:①各组大鼠吗啡戒断症状测定结果。②各组脑海马中神经元型一氧化氮合酶的表达变化。结果:实验纳入大鼠18只,全部进入结果分析。①各组大鼠吗啡戒断症状测定结果:胍丁胺吗啡组大鼠湿狗样抖动、咀嚼、激惹、流涎、腹泻、体质量减轻等戒断症状均明显低于吗啡组[(2.0±1.3),(5.0±1.1);(0.3±0.4),(1.8±0.7);(3.2±1.2),(6.8±3.1);(0.2±0.4),(1.2±0.9);(2.7±2.1),(6.7±2.1);(6.0±3.0),(12.8±2.7)次;P均<0.01],与盐水对照组基本相近(P>0.05)。②各组脑海马中神经元型一氧化氮合酶的表达变化:各组大鼠脑海马中神经元型一氧化氮合酶阳性神经元主要分布在CA1区,其胞浆被染成棕黄色,圆形的细胞核被苏木精染成淡紫色。胍丁胺吗啡组阳性神经元免疫荧光吸光度值较吗啡组显著降低(24.32±8.31,50.82±15.13,P<0.01),与盐水对照组基本相似(24.32±8.31,15.24±1.88,P>0.05)。结论:胍丁胺能抑制吗啡的戒断症状,降低吗啡戒断大鼠脑海马CA1区神经元型一氧化氮合酶的活性,海马一氧化氮通路参与胍丁胺抑制吗啡的戒断。     

Spinal γ-Aminobutyric Acid Interneuron Plasticity Is Involved in the Reduced Analgesic Effects of Morphine on Neuropathic Pain

Systemic administration of morphine increases serotonin (5-HT) in the spinal dorsal horn (SDH), which attenuates the analgesic effects of morphine on neuropathic pain through spinal 5-HT3 receptors. We hypothesized that dysfunction of the descending serotonergic system, including the periaqueductal gray (PAG), contributes to attenuate the efficacy of morphine on neuropathic pain through spinal 5-HT3 receptors and GABA neurons. Morphine (100 ng) injected into the PAG produced analgesic effects in normal rats, but not in spinal nerve ligation (SNL) rats. In vivo microdialysis showed that PAG morphine increased the SDH 5-HT concentration in both groups. Intrathecal injection of the 5-HT3 receptor antagonist ondansetron and the GABA_A receptor antagonist bicuculline attenuated the analgesic effects of PAG morphine in normal rats, but increased the effects in SNL rats. The increased analgesic effect of PAG morphine induced by bicuculline was reversed by pretreatment with the tropomyosin receptor kinase B (TrkB) antagonist K252a. Activation of spinal 5-HT3 receptors by 2-methyl-5-HT increased the GABA concentration in both groups. Morphine activates GABAergic interneurons in the SDH by activating descending serotonergic neurons. Functional changes in GABA_A receptors from inhibitory to facilitatory through the activation of TrkB receptors may contribute to the attenuated efficacy of morphine against neuropathic pain.PerspectiveAlthough morphine provides strong analgesia against acute pain, it has limited efficacy against neuropathic pain. This article demonstrates that functional changes in GABA_A receptors in the spinal dorsal horn after nerve injury might strongly contribute to the attenuation of opioid-induced analgesia for neuropathic pain.     

GABA(B) receptor activation in the ventral tegmental area inhibits the acquisition and expression of opiate-induced motor sensitization

Opiate-induced motor sensitization refers to the progressive and enduring motor response that develops after intermittent drug administration, and results from neuroadaptive changes in ventral tegmental area (VTA) and nucleus accumbens (NAc) neurons. Repeated activation of mu-opioid receptors localized on gamma-aminobutyric acid (GABA) neurons in the VTA enhances dopaminergic cell activity and stimulates dopamine release in the nucleus accumbens. We hypothesize that GABA(B) receptor agonist treatment in the VTA blocks morphine-induced motor stimulation, motor sensitization, and accumbal Fos immunoreactivity by inhibiting the activation of dopaminergic neurons. First, C57BL/6 mice were coadministered a single subcutaneous injection of morphine with intra-VTA baclofen, a GABA(B) receptor agonist. Baclofen produced a dose-dependent inhibition of opiate-induced motor stimulation that was attenuated by 2-hydroxysaclofen, a GABA(B) receptor antagonist. Next, morphine was administered on days 1, 3, 5, and 9 and mice demonstrated sensitization to its motor stimulant effects and concomitant induction of Fos immunoreactivity in the NAc shell (NAcS) but not NAc core. Intra-VTA baclofen administered during morphine pretreatment blocked the acquisition of morphine-induced motor sensitization and Fos activation in the NAcS. Intra-VTA baclofen administered only on day 9 blocked the expression of morphine-induced motor sensitization and Fos activation in the NAcS. A linear relationship was found between morphine-induced motor activity and accumbal Fos in single- and repeated-dose treatment groups. In conclusion, GABA(B) receptor stimulation in the VTA blocked opiate-induced motor stimulation and motor sensitization by inhibiting the activation of NAcS neurons. GABA(B) receptor agonists may be useful pharmacological treatments in altering the behavioral effects of opiates.     

Evidence for involvement of cyclic GMP phosphodiesterase in morphine tolerance

Preliminary evidence had suggested that changes in cyclic GMP (cGMP) hydrolysis via cyclic nucleotide phosphodiesterase(s) occurred during development of tolerance to morphine. To examine this finding further and its possible role in development of tolerance to morphine, rats (150-175 g) were injected with 1 ml of a sustained-release morphine preparation (40 mg/ml). Control rats received 1 ml of the oily vehicle. Antinociception, decreased locomotor activity, respiratory depression and mydriasis were measured at various times from 0.5 through 96 hr of exposure to the drug. Particulate and soluble cGMP hydrolysis were measured for the same time periods from periaqueductal gray (PAG), striatum, medulla and oculomotor nucleus, the brain areas believed to mediate the respective behaviors. Each of the behaviors except mydriasis showed development of complete tolerance (no difference from control behaviors) during the 96 hr of continuous exposure. During development of tolerance, particulate cGMP hydrolysis decreased in PAG and increased in striatum and medulla. Particulate cGMP hydrolysis was not altered in oculomotor nucleus, the brain area mediating mydriasis to which tolerance development was partial or incomplete. Significant changes in soluble cGMP hydrolysis occurred only in PAG before decline in the behavioral effect and did not appear to be involved in tolerance phenomena. Modulation of cyclic nucleotide levels by changes in particulate cGMP hydrolysis may produce or allow for development of complete tolerance to various morphine-induced behaviors.     

老龄大鼠脑缺血再灌注肺损伤机制研究

目的从ATP酶活性变化和自由基损伤方面研究老龄大鼠脑缺血再灌注肺脏损伤机制。方法青年(5月龄)和老龄(20月龄以上)大鼠均分为模型组和对照组,观察大鼠全脑缺血30min再灌注60min后肺脏组织形态和丙二醛(MDA)含量及超氧化物岐化酶(SOD)、ATP酶活性的变化。结果青年和老龄模型组大鼠肺脏组织均出现明显的病理改变,老龄模型组较青年模型组严重。老龄对照组肺组织MDA/SOD比值高于青年对照组组。青年模型组肺Ca2+-ATP酶活性低于青年对照组和老龄模型组。结论脑缺血再灌注肺损伤老龄大鼠较青年大鼠严重,Ca2＋-ATP酶活性的降低和自由基损伤可能是肺损伤发生的机制之一。     

Sensitization to repeated morphine injection in the rat: possible involvement of A10 dopamine neurons

Daily administration of morphine in rats produces an increase in the motor stimulant effect of subsequent morphine injections. This study was designed to characterize the behavioral sensitization produced by daily morphine and to evaluate the involvement of the mesolimbic and/or mesocortical dopamine (DA) neurons. Daily injection of morphine for 7 days produced an increase in both horizontal and vertical photocell counts. There was no difference in morphine levels in the blood or brain between daily morphine- and daily saline-treated rats at 30 or 90 min after acute injection of morphine. The increase was present for 60 days after initiating treatment and was associated with increases in locomotion, rearing, sniffing, grooming and bursting. Sensitization to morphine was prevented by pretreatment with naloxone i.p. or naltrexone methobromide injection into the ventral tegmental area (VTA; location of A10 DA perikarya projecting to limbic and cortical areas). In contrast, pretreatment with the same dose of naltrexone methobromide injected into the nucleus accumbens (limbic DA terminal field) or lateral ventricles did not significantly attenuate behavioral sensitization to morphine. Daily intra-VTA injections of the mu opioid agonist Tyr-D-Ala-Gly-NMe-Phe-Gly-ol enhanced the behavioral stimulant effect of acute morphine. The effects of daily morphine treatment on DA systems were evaluated by measuring DA metabolism, dopa accumulation and DA depletion in the VTA and various DA terminal fields including the prefrontal cortex, nucleus accumbens and striatum.(ABSTRACT TRUNCATED AT 250 WORDS)     

百草枯中毒大鼠急性肺损伤机制及姜黄素的干预研究

目的探讨急性百草枯中毒大鼠肺组织氧化应激及脂质过氧化损伤机制及姜黄素的干预作用。 方法将120只成年雄性SD大鼠按不同造模方法用随机数字表法分成对照组、百草枯中毒组、姜黄素干预组,每组大鼠40只。百草枯中毒组腹腔注射百草枯15 mg/kg,姜黄素干预组腹腔注射姜黄素200 mg/kg,15 min后腹腔注射百草枯15 mg/kg,对照组腹腔注射等容量的生理盐水。百草枯中毒组及姜黄素干预组于染毒后（对照组于腹腔注射后）3 h、6 h、24 h、3 d、7 d分别随机抽取8只大鼠取材。荧光实时定量PCR法测定各组大鼠肺组织中的转化生长因子（TGF）-β₁ mRNA的表达量,硫代巴比妥酸比色法、分光光度计比色法、黄嘌呤氧化酶法分别测定肺组织匀浆中丙二醛、髓过氧化物酶（MPO）、超氧化物歧化酶（SOD）活性,光镜下观察各组肺组织病理变化。 结果染毒后6 h、24 h、3 d、7 d,与对照组相比,百草枯中毒组和姜黄素干预组肺组织TGF-β₁ mRNA的表达量明显升高（F = 136.928、32.282、52.008、30.940,P均< 0.05）,丙二醛（F = 132.896、64.988、30.622、30.192）、MPO（F = 34.738、202.578、122.019、119.626）含量升高（P均< 0.05）,而SOD活力降低（F = 34.738、202.578、122.019、119.626,P均< 0.05）;与百草枯中毒组相比,姜黄素干预组各时间点肺组织TGF-β₁ mRNA表达量、丙二醛及MPO含量均降低（P均< 0.05）,肺组织SOD活力均升高（P均< 0.05）。 结论氧化应激及细胞膜脂质过氧化过程的启动可能是百草枯中毒急性肺损伤的机制之一,姜黄素可能通过阻止该过程减轻肺损伤的程度。     

吗啡、曲马多预先给药对急性心肌缺血大鼠背根神经节P物质和降钙素基因相关肽mRNA 表达的影响

目的 观察吗啡、曲马多预先给药对急性心肌缺血大鼠背根神经节内P物质mRNA(SP mRNA)和降钙素基因相关肽mRNA(CGRPmRNA)表达的影响.方法 健康成年雄性SD大鼠24只,体质量270～300 g,随机(随机数字法)分为四组(n=6):假手术组(S组)、单纯冠状动脉结扎组(Ⅰ组)、吗啡干预冠状动脉结扎组(M组)和曲马多干预冠状动脉结扎组(T组).S组大鼠开胸后在冠状动脉左前降支下穿线不结扎;Ⅰ组大鼠开胸后结扎冠状动脉左前降支;M组和T组大鼠经尾静脉分别注射吗啡1.25 mg·kg-1、曲马多12.5 mg·kg-1,15 min后结扎冠状动脉左前降支.各组在穿线或结扎冠状动脉左前降支3 h后开胸快速取脊髓胸段(T1-5)背根神经节采用反转录-聚合酶链反应法(RT-PCR)观察各组大鼠背根神经节内SPmRNA和CGRPmRNA的表达.应用单因素方差分析进行统计学分析.结果 Ⅰ组大鼠背根神经节内SPmRNA(0.93±0.02),α-CGRP mRNA(0.98±0.02)和β-CGRP mRNA (0.83±0.02)的表达均较S组(0.84±0.04),(0.86±0.01),(0.45±0.03)明显上调(P＜0.05);M组和T组SP mRNA(0.88±0.03),(0.88±0.04),α-CGRP mRNA(0.90±0.02),(0.90±0.01)和β-CGRP mRNA(0.67±0.02),(0.66±0.01)的表达均明显低于Ⅰ组(P＜0.05),但仍高于S组(P＜0.05);M组和T组二者间比较差异无统计学意义(P＞0.05).结论 吗啡、曲马多预先给药可降低急性心肌缺血大鼠背根神经节内SP mRNA和CGRP mRNA的表达.

Abstract：

Objective To investigate the effects of morphine and tramadol pre-emptive use on the expressions of substance P mRNA (SPmRNA) and calcitonin gene-related peptide mRNA (CGRPmRNA) in dorsal root ganglia (DRG) following acute myocardial ischemia in the rats. Method Twenty-four adult male SD rats weighing 270 to 300 g were randomly (random number) divided into four groups (n = 6, in each): group Ⅰ(sham operation), group Ⅱ (myocardial ischemia), group Ⅲ (morphine pre-emptive use) and group Ⅳ (tramadol pre-emptive use). The left anterior descending branch of coronary artery was occluded (CAO) for 3 hours in rats of group Ⅱ and Ⅳ.In group Ⅲ morphine 1.25 mg·kg-1 was injected through caudal vein 15 minutes before CAO.In group Ⅳ,tramadol 12.5 mg·kg-1 was daministered via caudal vein 15 minutes before CAO.In 3 hours after myocardial ischemia, the tissue of DRG (T1-5) were taken for detecting the expressions of SPmRNA and CGRPmRNA by using RT-PCR. One-way ANOVA was used for statistical analysis. Results In the tissue of DRG, the expressions of SPmRNA(0.93±0.02) ,α-CGRP mRNA(0.98±0.02) and β-CGRP mRNA(0.83 ± 0.02)were up-regulated in group Ⅱ compared with those in group Ⅰ (0.84±0.04),(0.86±0.01),(0.45±0.03) (P ＜0.05),and decreased markedly in group Ⅲ (0.88 ± 0.03) ,(0.90 ± 0.02), (0.67 ± 0.02) (P ＜ 0.05) and group Ⅳ (0.88±0.04) ,(0.90 ± 0.01),(0.66±0.01) (P ＜ 0.05), but showed no difference between group Ⅲ and Ⅳ (P ＞ 0.05). Conclusions Morphine and tramadol pre-emptive use can significantly inhibit the expressions of SPmRNA and CGRPmRNA in rat's dorsal root ganglia after CAO.     

大肠杆菌肺炎模型老龄大鼠的小肠分泌型IgA和肿瘤坏死因子的观测

目的：探讨老年肺炎时小肠损伤的发病机制。方法：复制大鼠大肠杆菌肺炎模型,分为青年对照组、青年模型组、老龄对照组和老龄模型组。观测肺脏和小肠组织病理改变及其组织含水量,肠内容物分泌型IgA（sIgA),IgA含量,血清和小肠组织肿瘤坏死因子（TNF）含量。结果：青年和老龄模型组肺和小肠组织损伤和含水量增高明显,其中老龄模型组大鼠肺组织损伤较青年模型组严重。青年模型组肠内容物sIgA含量的增高较青年对照组显著,老龄对照组sIgA高于青年对照组,老龄模型组sIgA低于老龄对照组。青年模型组和老龄模型组血清和小肠组织TNF的增高分别较青年对照组和老龄对照组显著,老龄模型组和血清和小肠组织TNF含量高于青年模型组。结论：TNF含量增多和sIgA含量变化与肺炎的肠道损伤发生发展有关密切关系,TNF增多及sIgA含量减少在老龄肺炎大鼠的变化更为显著。     

ATP-sensitive K+ channels and cellular actions of morphine in periaqueductal gray slices of neonatal and adult rats.

ATP-sensitive K+ (K(ATP)) channels were reported to be involved in morphine analgesia in vivo. The present study, using patch-clamp technique in brain slices of neonatal (P12-P16) and adult rats, investigated cellular actions of K(ATP) channel ligands and their interactions with morphine in the ventrolateral periaqueductal gray (PAG), a crucial site for morphine analgesia. In neonatal PAG neurons, morphine depressed evoked inhibitory postsynaptic currents (IPSCs) in almost all tested neurons and elicited an inwardly rectifying K+ current in one-third of tested neurons. Glibenclamide (1-10 microM), a K(ATP) channel blocker, did not affect the membrane current or synaptic current per se but also failed to affect the effects of morphine. No outward current was elicited upon using microelectrodes containing ATP-free internal solution. In adult neurons, morphine, at the concentration up to 300 microM, failed to activate K+ current in all 25 neurons tested but depressed IPSCs to a comparable extent as that in neonatal neurons. Glibenclamide also failed to alter the effect of morphine in adult neurons. The openers of K(ATP) channels, lemakalim (10-30 microM) and diazoxide (10-500 microM), unlike morphine, did not increase membrane currents in both neonatal and adult neurons. However, diazoxide induced a glibenclamide-sensitive outward current in hippocampal CA1 neurons. It is concluded that K(ATP) channels display little functional role per se and might not be involved in effects of morphine in the ventrolateral PAG. The correlation between the insensitivity in K+ channel activation and the less antinociceptive response to morphine in adults was discussed.     

A comparison of the sites at which pentazocine and morphine act to produce analgesia

Sites in the brain stem at which microinjected morphine can produce analgesia have been investigated for sensitivity to microinjections of pentazocine, which has been proposed to act at receptors different to those mediating the effects of morphine. Microinjection of 10 micrograms of pentazocine into the periaqueductal grey matter (PAG), the nucleus reticularis gigantocellularis (NRGC) and nucleus reticularis paragigantocellularis (NRPG) produced analgesia as determined by the tail flick response to noxious heat. Microinjection of pentazocine into nucleus raphe magnus (NRM) did not produce any discernible change in the nociceptive threshold measured with the tail flick test. Using the pain pressure test, analgesia was observed following microinjections of pentazocine into NRGC and NRPG, but not following microinjections into PAG or NRM. Morphine (3 and 5 micrograms) microinjected into PAG, NRM, NRGC or NRPG produced analgesia as determined by both heat and pressure tests. The analgesia produced by injection of pentazocine into the NRGC or NRPG was comparable to the analgesia produced by microinjection of 3 micrograms of morphine into these areas. The analgesia produced by injection of pentazocine into PAG was significantly less than that produced by 3 micrograms of morphine injected into PAG. Pretreatment with naloxone did not affect the analgesia produced by microinjection of pentazocine into NRGC or NRPG, but did antagonize the analgesia produced by injection of pentazocine into PAG. Naloxone blocked the analgesic effects of microinjected morphine. Analgesia produced by systemically given pentazocine was significantly reduced following microinjection of naloxone into PAG or NRM but not into NRGC or NRPG. The present data provide further evidence that the effects of pentazocine, a kappa agonist drug may be mediated by mechanisms different to those mediating the action of morphine, a mu agonist.