小鼠慢性酒精中毒及戒断过程中抑郁样行为的改变及其共病机制

 目的: 研究小鼠慢性酒精中毒及戒断过程中抑郁样行为的改变,进一步探讨酒精中毒与抑郁症的共病机制。方法: 构建新型慢性酒精中毒小鼠模型;实验分为正常对照组及慢性酒精7 d、14 d、21 d和28 d组。在第6、13、20和27天分别进行酒精偏好度测试,测试后戒断酒精1 d,随后次日进行抑郁行为学测试,测试结束后处死小鼠取海马与额叶皮层,采用高效液相色谱法测定5-羟色胺(5-HT)及去甲肾上腺素(NE)含量,采用免疫印迹法测定cAMP反应元件结合蛋白(CREB)和脑源性神经营养因子(BDNF)的含量。结果: 随着酒精饮酒天数及戒断次数的增加,小鼠表现出明显嗜酒现象,并且在强迫游泳和悬尾测试中,表现出明显的不动时间增加。7 d组小鼠额叶皮层内5-HT水平升高(P < 0.05),海马与额叶5-HT水平在21 d与28 d组降低(P < 0.01);7 d和14 d组小鼠海马与额叶NE水平无明显变化,21 d和28 d组NE水平降低(P < 0.05)。21 d和28 d组小鼠海马与额叶内p-CREB/CREB比值及BDNF表达水平明显下降(P < 0.05),7 d与14 d组无明显变化。结论: 酒精中毒、戒断阶段与抑郁的共病机制涉及5-HT。5-HT-cAMP-CREB-BDNF信号转导通路可能为酒精中毒与抑郁症的共病机制。     

高压氧通过激活CREB/BDNF信号通路减轻阿尔茨海默病小鼠海马神经元突触损伤

目的:探讨高压氧(hyperbaric oxygen,HBO)对阿尔茨海默病APP/PS1转基因(trangenic,TG)小鼠海马神经元突触损伤的影响及其作用机制。方法:将6月龄雄性APP/PS1 TG小鼠随机分为TG组、HBO组及环磷酸腺苷反应元件结合蛋白(cAMP response element binding protein,CREB)抑制剂H89组,每组10只;另取10只同龄雄性野生型(wild-type,WT)C57BL/6小鼠作为阴性对照组(WT组)。HBO和H89组小鼠进行高压氧治疗6个疗程;WT组及TG组小鼠不给予治疗。Morris水迷宫实验检测各组小鼠学习记忆能力;筑巢实验检测小鼠智力改变;尼氏染色检测各组小鼠海马神经元中尼氏体表达;real-time PCR检测小鼠海马区CREB及脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)mRNA的表达;Western blot检测小鼠海马区突触素(synapsin,SYN)、突触后致密区蛋白95(postsynaptic density protein 95,PSD95)、生长相关蛋白43(growth-associated protein 43,GAP43)、CREB、磷酸化CREB(p-CREB)及BDNF的蛋白水平。结果:与WT组相比,TG组小鼠学习记忆能力降低,筑巢分数显著降低,海马区尼氏体数量显著减少,CREB及BDNF mRNA相对表达显著减少,SYN、PSD95、GAP43、p-CREB及BDNF蛋白水平显著降低(P0. 05)。与TG组相比,HBO组小鼠学习与记忆能力改善,小鼠筑巢分数显著增加,海马区神经元排列整齐且尼氏体数量增加,CREB及BDNF mRNA相对表达显著增加,SYN、PSD95、GAP43、p-CREB及BDNF蛋白水平显著升高(P0. 05)。与HBO组相比,H89组小鼠学习记忆能力及筑巢分数显著降低,海马区尼氏体数量减少,CREB及BDNF mRNA相对表达显著减少(P0. 05),SYN、PSD95、GAP43、p-CREB及BDNF蛋白水平显著降低(P0. 05)。结论:HBO能改善APP/PS1 TG小鼠的学习记忆能力,其机制可能与激活CREB/BDNF信号通路,减轻小鼠海马神经元突触损伤有关。     

慢性间歇低氧对幼鼠认知及相关脑区CREB的影响

目的:观察慢性间歇低氧(CIH)对幼鼠认知的影响并探讨其潜在的机制。方法:取八臂迷宫训练成功的SPF级健康雄性SD幼鼠40只,随机分为:间歇低氧2周(2IH)、4周组(4IH),对照2周(2C)、4周组(4C),建立IH幼鼠模型,低氧结束后进行八臂迷宫测试,观察海马和前额叶皮层超微结构变化及cAMP反应元件结合蛋白(CREB)mRNA和磷酸化CREB蛋白的表达。结果:4组幼鼠的记忆错误次数比较均有显著差别(均P0.05);IH各组海马及前额叶皮层神经元均出现早期凋亡和变性,尤以4IH组最为明显,对照组则基本正常;与相应对照组相比,2IH、4IH组幼鼠海马和前额叶皮层CREB mRNA和p-CREB蛋白的表达水平显著降低(均P0.05),且以4IH组最低(均P0.01),差异显著,两对照组之间无显著差异(P0.05)。结论:慢性间歇低氧诱导海马和前额叶皮层神经元超微结构改变,还下调CREB的基因转录和抑制CREB蛋白磷酸化,抑制记忆相关蛋白的合成,这可能是引起学习记忆能力下降的重要机制之一。     

CCK-8及其受体拮抗剂对吗啡戒断大鼠额叶皮质及海马CREB与pCREB表达的影响

 目的：观察八肽胆囊收缩素（CCK-8）及其受体拮抗剂对吗啡戒断大鼠额叶皮质和海马cAMP反应元件结合蛋白（CREB）表达及其磷酸化（pCREB）的影响,初步探讨CCK-8调节吗啡戒断大鼠的受体后机制。方法：建立大鼠吗啡慢性依赖及纳络酮催促戒断模型,并给予CCK-8、CCK1受体拮抗剂L-364718和CCK2受体拮抗剂LY-288513慢性干预,应用Western blotting和免疫组织化学技术观察额叶皮质和海马CREB与pCREB 表达的变化。结果：（1） 正常组大鼠额叶皮质神经元胞浆、胞核均表达CREB蛋白,pCREB蛋白则仅在胞核中高表达;海马CA1区锥体细胞层神经元中,CREB蛋白在胞浆中高表达,胞核低表达,pCREB蛋白则仅在胞核中表达。（2） 慢性吗啡作用后CREB无明显变化,pCREB增加;急性纳洛酮催促戒断后CREB仍无明显变化,pCREB进一步升高。（3） 与戒断组相比,CCK-8、L-364718和LY-288513慢性干预对吗啡依赖戒断大鼠额叶皮质CREB蛋白表达无明显影响,pCREB蛋白表达均明显降低;L-364718和LY-288513慢性干预后,海马CREB与pCREB表达均明显降低,而CCK-8慢性干预对CREB蛋白表达无明显影响,仅pCREB蛋白表达明显降低。结论：CCK-8及其受体拮抗剂可能通过调节核转录因子CREB减轻吗啡戒断症状,并具有脑区特异性。     

长期亚麻醉剂量氯胺酮对青少年期食蟹猴前额叶和海马脑源性神经营养因子水平的影响

目的:探讨长期亚麻醉剂量氯胺酮对青少年食蟹猴自发活动、前额叶和海马脑源性神经营养因子(Brainderived neurotrophic factor,BDNF)和环磷腺苷效应元件结合蛋白(cAMP response element binding protein,CREB)的影响。方法:36只雄性食蟹猴(3.7-4.8岁)随机分为对照组,1个月、3个月和6个月氯胺酮组,氯胺酮组每日静脉注射氯胺酮(1mg/kg),对照组注射同体积生理盐水。比较给药前,给药1个月,3个月,6个月后动物的自发活动、前额叶和海马神经元形态及BDNF和CREB水平。结果:1个月氯胺酮组移动显著多于对照组;3个月组行走显著多于对照组;6个月组移动和攀爬显著低于对照组。氯胺酮导致前额叶和海马神经元数量减少,细胞排列紊乱,细胞间隙疏松、增大,部分细胞核固缩。氯胺酮组前额叶BDNF表达水平显著低于对照组;CREB表达水平在3个月组和6个月组显著低于对照组和1个月组。海马CREB表达水平在6个月组显著低于对照组、1个月组和3个月组。结论:长期亚麻醉剂量氯胺酮导致青少年食蟹猴自发活动由兴奋到抑制、前额叶和海马神经元损伤、BDNF和CREB表达降低。     

艾司西酞普兰对APP/PS1小鼠海马神经元突触功能及对BDNF-TrkB-CREB信号通路的影响

目的探讨艾司西酞普兰对APP/PS-1小鼠海马神经元突触功能及与BDNF-TrkB-CREB信号通路的关系。方法将7月龄APP/PS-1转基因小鼠随机分为模型组及艾司西酞普兰组,每组10只;另取10只同龄C57BL/6小鼠作为阴性对照组。给予10 mg/kg艾司西酞普兰灌胃治疗,连续8周,每天一次;对照组及模型组给予等体积生理盐水。Morris水迷宫检测各组小鼠学习记忆能力;尼式染色检测各组小鼠海马DG区尼氏体变化;酶联免疫吸附实验(ELISA)检测小鼠海马区乙酰胆碱酯酶(AChE)及胆碱乙酰转移酶(ChAT);Western blot检测小鼠海马区SYN、PSD95、GAP43、BDNF、TrkB、p-TrkB、CREB及p-CREB蛋白表达。结果艾司西酞普兰组改善APP/PS-1小鼠认知功能,小鼠逃避潜伏期减少,穿越平台次数增加,在目标象限停留时间延长,小鼠海马DG区神经元排列整齐且尼氏体数量增加,下调AChE,上调ChAT表达,且能增加SYN、PSD95及GAP43蛋白表达;此外,艾司西酞普兰还能显著增加小鼠海马区BDNF、p-TrkB及p-CREB蛋白表达,与模型组相比,差异有统计学意义(P0.05)。结论艾司西酞普兰改善小鼠海马神经元突触功能,提高APP/PS-1小鼠的学习记忆能力,可能与调控BDNF-TrkBCREB信号通路相关蛋白表达有关。     

补阳还五汤对血管性痴呆大鼠海马cAMP-PKA-CREB信号通路的影响

目的: 观察补阳还五汤对血管性痴呆大鼠海马组织环磷酸腺苷(cAMP)-蛋白激酶A(PKA)-cREB反应元件结合蛋白(CREB)信号通路的影响。方法: 将大鼠随机分为补阳还五汤组、尼莫地平组、模型组、假手术组。用改良Pulsinellis四血管阻断法建立血管性痴呆大鼠模型,分别给予相应的药物,连续30 d。利用放射免疫分析法检测海马组织cAMP含量,Western blotting法检测PKA催化亚基(PKAc)蛋白表达,电泳迁移率改变分析法检测CREB的DNA结合活性。结果: 与假手术组比较, 模型组大鼠海马组织cAMP含量、PKAc蛋白表达和CREB的DNA结合活性均降低(P<0.01);与模型组比较,补阳还五汤组和尼莫地平组cAMP含量、PKAc蛋白表达和CREB的DNA结合活性均升高(P<0.01)。结论: 补阳还五汤可增加血管性痴呆大鼠海马cAMP含量、PKAc蛋白表达和CREB的DNA结合活性,增强cAMP-PKA-CREB信号通路的作用。     

对药酸枣仁-合欢花对抑郁模型大鼠学习记忆能力及BDNF-MEK-ERK-CREB细胞信号转导通路的影响

目的:观察对药酸枣仁-合欢花对抑郁模型大鼠学习记忆能力及脑源性神经营养因子(BDNF)-丝裂原细胞外激酶(MEK)-细胞外信号调节蛋白激酶(ERK)-环磷腺苷反应元件结合蛋白(CREB)信号转导通路的影响,探讨对药酸枣仁(SZS)-合欢花(AJF)抗抑郁作用的机制。方法:将雄性SD大鼠按随机数字表法分为正常组(control)、模型组(CUMS)、对药酸枣仁-合欢花组(SZS+AJF)、盐酸文拉法辛组(Venlafaxine)、PD184161组(PD),采用孤养加慢性不可预知性温和应激(CUMS)复制抑郁症大鼠模型,并用Morris水迷宫实验评价各组大鼠不同时间学习记忆能力的改变。应用ELISA法测定血清BDNF水平,应用real time RT-PCR法测海马CREB、BDNF mRNA表达,应用Western Blot法测定海马ERK、p-ERK、p-RSK及p-CREB蛋白表达。结果:与Control组比较,CUMS组大鼠学习记忆能力下降(从第14 d开始有统计学意义,P 0. 05或P 0. 01),血清BDNF含量减少(P 0. 01),海马CREB、BDNF mRNA和ERK、p-ERK、p-RSK、p-CREB蛋白表达量减少(P 0. 05或P 0. 01)。与CUMS组比较,SZS+AJF组、Venlafaxine组、PD组大鼠学习记忆能力提高(从第14 d开始有统计学意义,P 0. 05或0. 01),血清BDNF含量增加(P 0. 05),海马CREB、BDNF mRNA和ERK、p-ERK、p-RSK、p-CREB蛋白表达量增加(P 0. 05或P 0. 01)。与SZS+AJF组比较,PD组大鼠学习记忆能力减少(第21 d有统计学意义,P 0. 05),血清BDNF含量减少(P 0. 05),海马CREB、BDNF mRNA和ERK、p-ERK、p-RSK、p-CREB蛋白表达降低(P 0. 05)。结论:对药酸枣仁-合欢花能够提高抑郁模型大鼠的学习记忆能力,具有抗抑郁效应,其作用机制可能与提高抑郁模型大鼠BDNF-MEK-ERK-CREB信号转导通路的关键因子表达有关。     

NGF对局灶性脑缺血再灌注大鼠顶叶皮质CREB表达的上调作用

为探讨外源性神经生长因子(NGF)对局灶性脑缺血再灌注大鼠顶叶皮质cAMP反应元件结合蛋白(CREB)和磷酸化CREB(p-CREB)表达的影响,用线栓法制作局灶性脑缺血再灌注模型,应用免疫组织化学、WesternBlotting和图像分析方法检测大鼠缺血侧顶叶皮质CREB和p-CREB的表达。结果显示:缺血再灌注组CREB表达较假手术组减少,p-CREB表达高于假手术组(P<0.05);NGF组CREB和p-CREB表达高于缺血再灌注组(P<0.05)。以上结果表明NGF明显上调局灶性脑缺血再灌注大鼠顶叶皮质CREB和p-CREB的表达,NGF对缺血神经元的保护作用可能通过上调CREB和p-CREB的表达来实现。     

解郁丸对WKY大鼠的抑郁样行为及海马和前额叶皮层BDNF表达的影响

目的:观察解郁丸对Wistar-Kyoto(WKY)大鼠抑郁样行为及脑源性神经营养因子(BDNF)在海马和前额叶皮层表达的影响,探讨其抗抑郁作用及相关机制。方法:成年雄性WKY大鼠为内源性抑郁动物模型,选取同品系Wistar大鼠作为空白对照组,WKY大鼠随机分为模型组、西酞普兰组和解郁丸组,分别灌胃给药21 d后,用糖水偏好实验及强迫游泳实验观察各组大鼠抑郁行为变化;采用免疫荧光法和Western blot法检测海马及前额叶皮层BDNF表达水平的变化。结果:WKY大鼠表现出明显的抑郁样行为,海马及前额叶皮层的BDNF表达量显著下降,且海马区神经元轴突减少(P0.01);在药物治疗后,WKY大鼠的抑郁样行为明显减少,BDNF在海马及前额叶皮层中的表达增加,且轴突数目也增加(P0.01)。结论:解郁丸能有效减少WKY大鼠的抑郁样行为;BDNF是其抗抑郁作用发挥的关键因子。本研究也进一步验证BDNF参与抑郁的发生发展过程。     

磷酸二酯酶4抑制剂咯利普兰逆转慢性束缚应激诱导的大鼠抑郁和焦虑样行为

目的: 探讨磷酸二酯酶4(PDE4)特异性抑制剂咯利普兰(rolipram)对抗慢性应激诱导的抑郁和焦虑样行为的分子机制。方法: (1)将40只SD大鼠分为4组(每组10只):空白对照组、模型组、阳性对照药氯化锂(LiCl)组及rolipram组,并进行应激前旷场实验。给予慢性束缚应激21 d 后,分别进行强迫游泳、高架十字迷宫及应激后旷场实验。最后一次行为学实验结束后立即处死动物并取双侧海马组织,免疫印迹法检测海马内磷酸化cAMP反应元件结合蛋白(p-CREB)、脑源性神经营养因子(BDNF)、磷酸化丝氨酸残基21糖原合成酶激酶3α(p-Ser21-GSK3α)、磷酸化丝氨酸残基9糖原合成酶激酶3β(p-Ser9-GSK3β)、磷酸化酪氨酸残基279糖原合成酶激酶3α(p-Tyr279-GSK3α)、磷酸化酪氨酸残基216糖原合成酶激酶3β(p-Tyr216-GSK3β)、总糖原合成酶激酶3α(total GSK3α)及总糖原合成酶激酶3β(total GSK3β)的表达。(2)30只SD大鼠平均分为6组,双侧海马CA1区手术埋管并恢复7 d 后进行慢性应激处理21 d,并在每次应激前微量注射蛋白激酶A(PKA)的拮抗剂H89,并腹腔注射LiCl和rolipram。双侧海马用于检测PDE4D、p-CREB和p-Ser9-GSK3β的表达。结果: (1)应激前各组动物自主活动能力无显著差异,应激14 d及21 d后应激组与空白对照组相比体重显著下降,LiCl及rolipram均显著逆转了应激对体重的下调作用。应激显著增加了强迫游泳实验中动物的不动时间,减少了攀爬时间和高架十字迷宫实验中进入开臂的次数及时间,表现出抑郁和焦虑样行为,而LiCl及rolipram均显著逆转了慢性束缚应激诱导的上述行为障碍。免疫印迹结果显示rolipram可显著逆转应激对p-CREB、BDNF、p-Ser21-GSK3α和p-Ser9-GSK3β表达的下调作用,而LiCl仅显著上调p-Ser21-GSK3α及p-Ser9-GSK3β的表达。各组p-Tyr279-GSK3α、p-Tyr216-GSK3β、total GSK3α及total GSK3β的表达无显著差异。(2)慢性应激诱导了大鼠海马内PDE4D表达的上调,PKA、p-CREB及p-Ser9-GSK3β的下调。Rolipram显著逆转了上述效应,且H89显著阻断了Rolipram的药物效应。结论: Rolipram抗抑郁及抗焦虑作用不仅通过CREB/BDNF信号通路,而且还有GSK3 抑制性丝氨酸残基磷酸化信号通路的参与,且CREB介导的信号转导通路对GSK3 抑制性丝氨酸残基磷酸化信号通路发挥重要调节作用。     

Rescuing prefrontal cAMP-CREB pathway reverses working memory deficits during withdrawal from prolonged alcohol exposure

Both human and animal studies indicate that alcohol withdrawal following chronic alcohol consumption (CAC) impairs many of the cognitive functions which rely on the prefrontal cortex (PFC). A candidate signaling cascade contributing to memory deficits during alcohol withdrawal is the protein kinase A (PKA)/cAMP-responsive element binding (CREB) cascade, although the role of PKA/CREB cascade in behavioral and molecular changes during sustained withdrawal period remains largely unknown. We demonstrated that 1 week (1W) or 6 weeks (6W) withdrawal after 6-month CAC impairs working memory (WM) in a T-maze spontaneous alternation task and reduces phosphorylated CREB (pCREB) in the PFC but not the dorsal CA1 region (dCA1) of the hippocampus compared with CAC and water conditions. In contrast, both CAC-unimpaired and withdrawn-impaired mice exhibited decreased pCREB in dCA1 as well as reduced histone H4 acetylation in PFC and dCA1, compared with water controls. Next, we showed that enhancing CREB activity through rolipram administration prior to testing improved WM performance in withdrawn mice but impaired WM function in water mice. In addition, WM improvement correlates positively with increased pCREB level selectively in the PFC of withdrawn mice. Results further indicate that direct infusion of the PKA activator (Sp-cAMPS) into the PFC significantly improves or impairs, respectively, WM performance in withdrawn and water animals. In contrast, Sp-cAMPS had no effect on WM when infused into the dCA1. Collectively, these results provide strong support that dysregulation of PKA/CREB-dependent processes in prefrontal neurons is a critical molecular signature underlying cognitive decline during alcohol withdrawal.     

右美托咪定对抑郁症大鼠行为及海马BDNF和mTOR蛋白表达的影响

目的:观察右美托咪定(DEX)对抑郁症大鼠行为及海马脑源性神经营养因子(BDNF)和哺乳动物雷帕霉素靶蛋白(mTOR)表达的影响并探讨其机制。方法:实验设5组,即假手术(sham)组、抑郁症模型(model)组及DEX(2.5、5和10μg/kg)组,每组12只大鼠。抑郁症动物模型采用卵巢摘除加慢性不可预知性温和应激法制备。DEX各剂量组大鼠连续腹腔注射给药21 d。强迫游泳及旷场实验观察大鼠行为变化。Morris水迷宫实验评价大鼠空间学习和记忆能力。海马神经元病理变化采用尼氏染色法检测。大鼠海马白细胞介素1β(IL-1β)、IL-6和肿瘤坏死因子α(TNF-α)mRNA的表达水平采用RT-qPCR法检测。Western blot检测海马IL-1β、IL-6、TNF-α和BDNF蛋白表达水平及蛋白激酶A(PKA)、cAMP反应元件结合蛋白(CREB)、原肌球蛋白相关激酶B(TrkB)、磷脂酰肌醇3-激酶(PI3K)、蛋白激酶B(Akt)和mTOR蛋白的磷酸化水平。结果:与model组相比,DEX各剂量组大鼠强迫游泳不动时间明显降低,自发活动明显增加,逃避潜伏期明显降低,穿越平台次数明显增加(P<0.05或P<0.01),海马神经元损伤显著减轻,IL-1β、IL-6和TNF-α的表达水平明显降低,PKA、CREB及TrkB的磷酸化水平和BDNF表达水平均明显升高,同时PI3K/Akt/mTOR信号通路蛋白磷酸化水平明显上调(P<0.01)。结论:右美托咪定可改善抑郁症大鼠行为及空间学习和记忆能力,其机制可能与其抗炎、调节海马BDNF蛋白表达及TrkB磷酸化水平、进而激活PI3K/Akt/mTOR信号通路有关。     

可乐定对慢性脑缺血大鼠学习记忆及ERK信号通路相关蛋白的影响

目的:研究可乐定(clonidine)对大鼠慢性脑缺血(ischemia)后认知功能的影响并初步探讨其神经保护作用机制。方法:将45只SD大鼠随机分为假手术(sham)组、脑缺血(ischemia)组和可乐定(clonidine)组,每组15只。通过大脑中动脉栓塞法建立慢性脑缺血大鼠模型。各组大鼠在术前1周连续灌胃给药,其中clonidine组每日以clonidine 100μg/kg灌胃,sham组和ischemia组以等体积蒸馏水灌胃。术后4周,用Morris水迷宫法检测各组大鼠的学习记忆能力,免疫组织化学法和Western blot法检测非磷酸化和磷酸化细胞外信号调节激酶1/2(ERK1/2)及环磷腺苷效应元件结合蛋白(CREB)的蛋白水平。结果:Morris水迷宫实验结果显示,与假手术组相比,脑缺血组大鼠学习和记忆能力减弱;与脑缺血组相比,可乐定组大鼠学习和记忆能力增强。免疫组织化学法和Western blot法检测结果表明,与假手术组比较,脑缺血组大鼠海马组织中p-ERK1/2和CREB的蛋白水平均增加(P0.01);与脑缺血组相比,可乐定组大鼠海马组织中p-ERK1/2和p-CREB的蛋白水平降低(P0.01)。结论:可乐定可能通过调节ERK信号通路相关蛋白ERK1/2和CREB的表达,从而改善脑缺血再灌注引起的学习记忆障碍。     

The cAMP-dependent protein kinase A and brain-derived neurotrophic factor expression in lymphoblast cells of bipolar affective disorder

BACKGROUND: Abnormalities in cAMP signaling and altered expression of downstream targets such as brain-derived neurotrophic factor (BDNF) have been postulated in patients with bipolar disorder (BD). METHODS: The PKA activity and levels of (3)H-cAMP binding to PKA R regulatory subunits were measured in lymphoblasts from 10 BD and 10 control subjects. In addition, the possibility that BDNF expression could be altered in these cells has been explored. RESULTS: Results indicate that PKA activity significantly increased (t-test; P<0.01), whereas the (3)H-cAMP binding to PKA R subunits decreased in cells from BD (t-test; P<0.02). The presence of 10 microM Sp-cAMP in culture 24 h before cell harvesting induced an increase in enzyme activity and a decrease in (3)H-cAMP binding sites (t-test; P<0.01), with a significant difference between BD and controls (t-test; P<0.01). This presence of Sp-cAMP also results in increased BDNF expression (t-test, P<0.01), but neither in resting cells, nor in stimulated cells, was any difference observed in BDNF expression between BD and controls (t-test, NS). Limitations: This study was conducted on a peripheral model cell, whose importance of BDNF is unknown. CONCLUSIONS: These data suggest that the upregulation of cAMP signaling observed in BD patients results in the normalization of the BDNF expression. Studies on signal transduction, gene expression and pathologies have implications for development of novel treatments.     

An inhibitor of cAMP-dependent protein kinase induces behavioural and neurological antidepressant-like effects in rats

Although it is well established that cyclic adenosine monophosphate (cAMP) signalling via cAMP-dependent protein kinase (PKA)within neurons plays an important role in depression and antidepressant treatment, the importance of several newly discovered targets that function independently from PKA, such as exchange protein activated by cAMP (Epac), remains unexplored in this regard. In this study we used a cAMP analogue that inhibits PKA but not Epac (Rp-8-Br-cAMP), to explore the modifying actions of these two targets on immobility in the forced swim test (FST) and cerebellar cAMP response element binding protein (CREB) phosphorylation in rats. In addition, we assessed central cAMP and cGMP levels and investigated the involvement of cGMP-dependent protein kinase (PKG) on any observed effects by using a selective PKG inhibitor (Rp-8-Br-PET-cGMPS).Interestingly, Rp-8-Br-cAMPS strongly reduced immobility in the FST and induced an increase in the phosphorylation of CREB in the cerebellum, effects that were unaltered by the co-administration of Rp-8-Br-PET-cGMPS. Furthermore, Rp-8-Br-cAMPS increased the accumulation of cAMP and cGMP in the hippocampus, frontal cortex and cerebellum of these rats. Together, these results suggest that in addition to activating PKA, elevated cAMP may also stimulate other targets that mediate antidepressant activity. According to the pharmacodynamic profile of Rp-8-Br-cAMPS and taking into consideration what has recently been discovered regarding the cAMP signalling system, a likely candidate is the guanine nucleotide exchange factor, Epac.     

酒精处理影响青春期大鼠海马CA1区BDNF和TrkB的表达

为探讨青春期饮酒致学习记忆力下降的可能机制,本研究观察了青春期大鼠酒精处理后海马CA1区脑源性神经营养因子(BDNF)和酪氨酸激酶受体B(TrkB)的表达变化。实验选用30d龄SD雄性大鼠,以25%的酒精按8g/kg/d灌胃,连续灌7d,动物分别在停酒后0d,3d,7d和14d处死;对照组以等量生理盐水代替酒精按同样方法处理。用免疫组织化学方法(ABC法)检测海马CA1区BDNF和TrkB的表达,Motic3.2图像分析系统测定免疫阳性产物的平均灰度值。结果显示,BDNF的表达在停酒后0d和14d,实验组与相应对照组相比差异无显著性(P>0.05);3d显著升高(P<0.05);7d明显下降(P<0.05)。TrkB的表达在停酒后0d,3d,7d,实验组与相应对照组相比差异无显著性(P>0.05);14d显著下降(P<0.05)。以上结果提示,BDNF表达的相对不足可能是青春期饮酒致学习记忆力持续性下降的原因之一。     

电针对海洛因成瘾大鼠学习记忆及海马CREB表达的影响

目的：探讨电针对海洛因成瘾大鼠学习记忆的影响及作用机制。方法130只Wistar大鼠随机分为对照组、海洛因成瘾组（简称成瘾组）和海洛因成瘾后作电针治疗组（简称电针组）。进行跳台实验测试大鼠学习记忆能力,并用免疫组化方法检测鼠脑海马环磷酸腺苷反应元件结合蛋白（CREB）和磷酸化CREP（P—CREB）的表达。结果：成瘾组大鼠学习记忆下降（P％0．01）,电针组大鼠学习记忆有所改善（P〈0．01）;成瘾组大鼠海马CREB、P—CREB表达较对照组增高（P〈0．05）,电针组更高（P〈0．01）。结论：电针治疗可在一定程度上对抗海洛因成瘾大鼠所致的学习记忆下降,其机制可能与海马内CREB、P—CREB表达变化有关;CREB、PCREB参与学习记忆及海洛因成瘾的形成。     

PACAP38 improves airway epithelial barrier destruction induced by house dust mites allergen

PurposeThis study aimed to investigate the mechanism of PACAP38 on house dust mite (HDM)-induced asthmatic airway epithelial barrier destruction.MethodsThe HDM-induced asthma mice model and 16HBE cell model was established respectively. The enzyme linked immunosorbent assay (ELSIA), cell count and immunohistochemical assay were performed on mice in control group, HDM group and PACAP38 + HDM group.The cAMP/PKA activity, p-CREB and total CREB expression, TEER and the FITC-DX were investigated on cells in control-16HBE group, HDM-16HBE group and PACAP38 + HDM-16HBE group.ResultsThe levels of IL-4 and IL-5 in the HDM group were significantly higher than those in the control group (P < 0.05), while the above indexes in the PACAP38 + HDM group were lower than those in the HDM group (P < 0.05). E-cadherin, β-catenin, ZO-1 and occludin in the control group were highly immunoreactive in airway epithelial cells, whereas connexin staining was attenuated after HDM induction. The TEER level, cAMP levels and PKA activity were decreased, while FITC-DX transmittance was increased in HDM-16HBE group (P < 0.05) compared with the control-16HBE group.ConclusionPACAP38 could reduce the airway inflammation, weaken the AJC protein heterotopia and activate cAMP/PKA signaling pathway in HDM-induced asthma, which indicate that PACAP38 may be an important contributor in HDM-induced asthma.