戊四氮点燃癫(癎)大鼠海马巢蛋白和骨形成蛋白-4的表达研究

目的观察巢蛋白(nestin)和骨形成蛋白4(BMP4)基因在戊四氮(PTZ)点燃癫大鼠海马中的表达,并探讨两者与癫发病机制的关系。方法将81只成年雄性SD大鼠随机分为实验组(n=54)和对照组(n=27)。实验组采用PTZ点燃癫大鼠,按点燃中的不同时相点,又随机分为9组。用免疫组化技术、地高辛标记特异性寡核苷酸探针原位杂交组织化学技术,观察海马nestin和BMP4表达的变化。结果nestin阳性细胞在PTZ注射后3d开始出现在齿状回、CA3区和CA1区,到7d达到高峰,以后逐渐减少。BMP4在PTZ注射后7d开始增多,在点燃后1d达到高峰,以后逐渐减少,主要分布在齿状回、CA3区和CA1区。结论PTZ点燃可引起海马内星形胶质细胞增生、活化和神经发生,这可能是癫海马组织胶质化、神经元可塑性的病理基础;BMP4可能在PTZ癫形成过程中起重要作用。     

脑源性神经营养因子修饰的神经干细胞移植对阿尔茨海默病大鼠的学习及p75表达的影响

目的研究脑源性神经营养因子(BDNF)修饰的神经干细胞(NSC)移植对阿尔茨海默病大鼠的学习及p75表达的影响。方法 36只SD成年大鼠被选为受试对象。采用Aβ1-40立体定向注射法制作阿尔茨海默病模型(AD),并将AD模型大鼠随机分为3组:BDNF修饰的神经干细胞(BDNF-NSC)移植组、神经干细胞移(NSC)植组和溶剂(Vehicle)对照组(n=6),然后分别向这3组大鼠的海马区注入500μl的BDNF-NSC悬液(5×105)、NSC悬液(5×105)和相同剂量的不含细胞的培养基。注射4w后,采用Y迷宫方法检测AD大鼠的空间学习和记忆能力,随之用过量麻醉的方法处死受试大鼠,立即取脑并分别采用免疫组织化学方法检测BDNF-NSC在海马区的表达和Western blot法检测p75蛋白在海马区的表达。结果 BDNF-NSC组大鼠的行为学能力较NSC组和Vehi-cle组明显提高(P<0.05),同时免疫组化检测显示在海马区的BDNF-NSC阳性细胞数明显增多而Western blot检测显示p75蛋白在该区的表达显著降低(P<0.05)。结论 BDNF修饰的神经干细胞能够通过抑制海马区p75表达来防止由Aβ1-40造成的神经损害。     

丰富环境促进颞叶癫(痫)大鼠神经发生及其机制的研究

目的 探讨丰富环境对颞叶癫(痫)大鼠齿状回新生细胞分化和存活的影响及其相关分子机制.方法 成年Wistar 大鼠随机分为4组:假手术组、丰富环境+假手术组、癫(痫)组、丰富环境+癫(痫)组,各组均n=15.大鼠侧脑室注射海人酸制作颞叶癫(痫)模型.丰富环境干预30 d后,应用免疫荧光技术观察大鼠海马齿状回的新生细胞分化和存活情况,用Western blot方法检测各组海马脑源性神经营养因子(BDNF)、cAMP应答元件结合蛋白(pCREB)、蛋白激酶A(PKA)表达水平.结果 丰富环境+假手术组、丰富环境+癫(痫)组齿状回新生细胞标记物(BrdU)和新生成熟神经细胞标记物(BrdU/NeuN)阳性细胞数分别多于假手术组、癫(痫)组(P＜0.05),而新生星形胶质细胞BrdU/GFAP阳性细胞数无统计学意义,并且丰富环境+假手术组、丰富环境+癫(痫)组海马BDNF和pCREB蛋白表达水平分别高于假手术组、癫(痫)组(P＜o.05),而PKA蛋白表达水平无增高.结论 丰富环境可能通过增强pCREB/BDNF通路促进成年颞叶癫(痫)大鼠海马齿状回的神经发生.     

Orexin-1受体拮抗剂对慢性点燃癫大鼠学习记忆的影响及海马神经细胞的增殖变化

目的:研究orexin-1受体(OX1R)拮抗剂(SB334867,SB)对戊四氮(PTZ)慢性点燃癫大鼠空间学习记忆能力及海马齿状回神经细胞增殖的影响。方法:Wistar大鼠随机分为①对照组[腹腔和侧脑室均注射生理盐水(NS)];②PTZ组(腹腔注射PTZ+侧脑室注射NS);③PTZ+orexin-A(OXA)组(腹腔注射PTZ+侧脑室注射OXA);④PTZ+SB组(腹腔注射PTZ+侧脑室注射SB);⑤PTZ+SB+OXA组(腹腔注射PTZ+侧脑室注射SB和OXA)。观察各组大鼠的空间学习记忆能力及海马齿状回区BrdU+和BrdU+/NeuN+细胞的表达。结果:与PTZ+OXA组比较,PTZ+SB+OXA组大鼠逃避潜伏期延长、穿越平台象限的次数减少(P<0.05)。免疫荧光显示,PTZ+OXA组大鼠齿状回区BrdU+和BrdU+/NeuN+细胞表达增多(P<0.01),而PTZ+SB+OXA组大鼠齿状回区BrdU+/NeuN+细胞表达比PTZ+OXA组减少(P<0.01)。结论:OXA通过OX1R能改善癫大鼠的空间学习记忆能力,可能与OX1R介导的海马齿状回神经细胞增殖与分化作用有关。     

颞叶癫(癎)大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化

目的研究颞叶癫大鼠海马轴突导向分子Sema3F及其受体Np2表达的变化。方法给SD大鼠腹腔注射匹罗卡品、氯化锂制作颞叶癫模型。用免疫组化法和原位杂交技术对致后不同时间点大鼠海马CA1区、CA3区、齿状回的Sema3F mRNA、Np2 mRNA和蛋白表达进行检测,并与正常对照组比较。结果颞叶癫大鼠致后7d、15d,海马CA1区、CA3区Sema3F mRNA、Np2 mRNA和蛋白的表达明显低于正常对照组(P<0.05~0.01),致后30d、60d表达与正常对照组差异无统计学意义;而齿状回Sema3F mRNA、Np2 mRNA和蛋白的表达与正常对照组的差异无统计学意义。结论颞叶癫大鼠海马CA1区、CA3区Se-ma3F、Np2表达在致后早期明显下调,而在慢性期恢复正常。     

红景天苷和脑源性神经营养因子与神经干细胞共移植对致鼠神经干细胞定向分化的研究

目的：探讨红景天苷和脑源性神经营养因子（BDNF）、神经干细胞（NSCs）共移植对致鼠NSCs定向分化影响。方法：将戊四氮致大鼠分为模型组、NSCs组、NSCs＋BDNF组和NSCs＋BDNF＋红景天苷组。取新生大鼠海马组织,将培养的NSCs与BDNF＋红景天苷＋BDNF和基础培养基分别移植至致鼠海马组织中,苏木精-伊红染色及免疫组化检测不同时间点5-溴脱氧尿嘧啶核苷（BrdU）、谷氨酸脱羧酶（GAD65）阳性细胞数,并观察大鼠行为学改变。结果：NSCs＋BDNF＋红景天苷共移植组与其他组比较,各时间点BrdU、GAD65阳性细胞数均增多（P〈0.05）。第3周开始,大鼠癫发作次数最少（P〈0.05）。结论：BDNF与红景天苷联合有利于神经干细胞向γ-氨基丁酸能神经元分化。两者联合移植至致鼠后能减少大鼠的癫发作次数。     

脑室内灌注神经肽Y对戊四氮致痫大鼠海马结构内脑源性神经营养因子表达的影响

目的 :探讨脑室内注入神经肽 Y(Neuropeptide Y,NPY)对戊四氮 (PTZ)致痫大鼠海马结构内脑源性神经营养因子 (Brain- derived Neurotrophic Factor,BDNF)表达的影响。方法 :将 18只健康雄性 Wistar大鼠随机分为 NPY实验组 (n=10 )和对照组 (n=8)。 NPY实验组 ,于 PTZ造模前给予侧脑室注射 NPY(6 nmol/ 10μl) ,对照组给予等容量生理盐水。侧脑室注射后 5分钟 ,腹腔注射 PTZ(6 0 mg/ kg) ,观察痫性发作持续时间并于痫性发作后 2小时处死动物。用免疫组化方法观察海马齿状回 (DG)和 CA1区 BDNF的免疫反应性。结果 :NPY实验组痫性发作时间短于对照组 (P<0 .0 0 1)。实验组 DG颗粒细胞层、分子层的 BDNF免疫反应性高于对照组相应各层 ,各组比较有显著性差异。实验组CA1区锥体细胞层、放射层及腔隙层免疫反应性均高于对照组相应各层 ,各组比较有显著性差异。实验组 DG分子层和 CA1区放射层及腔隙层免疫反应性分别高于颗粒细胞层和锥体细胞层免疫反应性 ,各组比较有显著性差异。 CA1区分子层未见 BDNF免疫反应性表达。结论 :脑室内注射 NPY可缩短痫性发作时间 ,并促进致痫大鼠海马内 BDNF的表达。     

神经干细胞移植后在视神经损伤大鼠视网膜内表达BDNF的研究

目的探讨神经干细胞(NSC)移植入视神经损伤(ONI)的SD大鼠玻璃体下腔后在视网膜内表达脑源性神经营养因子(BDNF)的情况,为进一步探索NSC移植治疗视神经损伤提供实验依据。方法体外培养NSC,其上清液采用酶联免疫吸附实验(ELISA)定量分析BDNF含量。取34只SD大鼠,其中4只作为正常对照,另外30只制作成右眼ONI模型并随机等分为N组和P组。ONI术后随即向N组大鼠右眼玻璃体下腔注入定量NSC,P组注入等量PBS,并采用半定量RT-PCR方法检测正常大鼠视网膜及N组、P组大鼠术后第3天、1周、2周、3周、4周时视网膜BDNFmRNA的表达水平,行统计学分析。结果正常视网膜内可见BDNF表达;N组与P组大鼠视网膜内表达BDNF的量除第1周差异无统计学意义外,余时间段N组均高于P组。结论NSC能促使视神经损伤大鼠视网膜高表达BDNF,NSC移植治疗视神经损伤值得进一步深入研究。     

银杏叶提取物对戊四氮致大鼠海马内NMDA受体和HSP70表达的影响

目的探讨银杏叶提取物抗癫的分子生物学机制。方法在SD大鼠腹腔内注射戊四氮(PTZ)诱发大鼠惊厥急性发作,制作癫模型。应用免疫组化技术观察银杏叶提取物(GBE)对点燃癫大鼠海马内NMDA受体和HSP70表达的影响。结果戊四氮致组大鼠海马内NMDA受体表达明显高于正常对照组,银杏叶提取物干预组明显低于戊四氮致组,银杏叶提取物干预组与正常对照组之间差异无显著性意义。戊四氮致组大鼠海马内HSP70表达明显高于正常对照组,银杏叶提取物干预组明显高于戊四氮致组。结论银杏叶提取物可降低癫大鼠海马内NMDA受体的表达,其可能通过此种机制来抑制癫的发生和发展。银杏叶提取物可增加癫大鼠海马内HSP70的表达,以此来减轻癫发作后所致的神经元损伤。     

丰富环境促进颞叶癫癇大鼠神经发生及其机制的研究

目的探讨丰富环境对颞叶癫癇大鼠齿状回新生细胞分化和存活的影响及其相关分子机制。方法成年Wistar大鼠随机分为4组:假手术组、丰富环境+假手术组、癫癇组、丰富环境+癫癇组,各组均n=15。大鼠侧脑室注射海人酸制作颞叶癫癇模型。丰富环境干预30 d后,应用免疫荧光技术观察大鼠海马齿状回的新生细胞分化和存活情况,用Western blot方法检测各组海马脑源性神经营养因子(BDNF)、cAMP应答元件结合蛋白(pCREB)、蛋白激酶A(PKA)表达水平。结果丰富环境+假手术组、丰富环境+癫癇组齿状回新生细胞标记物(Brd U)和新生成熟神经细胞标记物(Brd U/Neu N)阳性细胞数分别多于假手术组、癫癇组(P0.05),而新生星形胶质细胞Brd U/GFAP阳性细胞数无统计学意义,并且丰富环境+假手术组、丰富环境+癫癇组海马BDNF和pCREB蛋白表达水平分别高于假手术组、癫癇组(P0.05),而PKA蛋白表达水平无增高。结论丰富环境可能通过增强p CREB/BDNF通路促进成年颞叶癫癇大鼠海马齿状回的神经发生。     

重组大鼠质粒pEGFP-GDNF的构建及大鼠胚胎神经干细胞转染的研究

目的 探讨携带GDNF基因的神经干细胞表达载体的构建方法。方法 采用RT-PCR方法从大鼠胎脑组织总RNA中扩增出该基因的全序列cDNA，并克隆到增强型绿色荧光蛋白（EGFP）报告基因的真核表达载体pEGFP-C1中，经酶切鉴定及测序分析对重组质粒pEGFP-GDNF作进一步鉴定。采用阳离子脂质体将重组质粒pEGFP-GDNF转染至鼠胚胎神经干细胞。结果 大鼠GD-NF cDNA已正确地克隆到真核表达载体pEGFP-C1中，而构建成重组大鼠质粒pEGFP-GDNF，GDNF基因在细胞中可稳定表达。结论 神经干细胞可直接作为基因靶细胞，能被GDNF真核细胞表达载体pEGFP-GDNF有效的感染。     

男性慢性精神分裂症患者血清脑源性神经营养因子和胶质源性神经营养因子水平及认知功能的对照研究

目的:探讨慢性精神分裂症患者血清脑源性神经营养因子(BDNF)、胶质源性神经营养因子水平(GDNF)和神经认知功能的变化及它们之间关系。方法:入组慢性精神分裂症患者57例和正常对照39名。采用阳性与阴性症状量表(PANSS)评估患者的精神症状。使用酶联免疫吸附法检测血清BDNF、GDNF蛋白水平,采用数字划消测验、连线测验(TMT)、WMS-III空间广度测验(WMS-III SST)、定步调连续加法任务测验(PASAT)、Stroop测验、木块图评估神经认知功能。结果:患者组血清BDNF水平低于对照组,差异有统计学意义(t=9.112,P0.01),患者组血清GDNF与对照组相比差异无统计学意义(t=1.513,P0.05)。患者组数字划消测验、TMT-A、TMT-B、Stroop测验、木块图、WMS-III SST逆行分、PASAT成绩均差于对照组(P0.05)。患者组血清BDNF水平与PANSS阳性症状分、数字划消测验中的错误个数呈负相关(分别为r=-0.295,P=0.026;r=-0.262,P=0.049),血清GDNF水平与Stroop色词干扰测验分呈正相关(r=0.263,P=0.048)。结论:慢性稳定期的精神分裂症患者仍存在广泛的神经认知损害。BDNF可能是精神分裂症的一种素质性标记,可能参与了患者的注意障碍。     

Brain-derived neurotrophic factor-mediated effects on mitochondrial respiratory coupling and neuroprotection share the same molecular signalling pathways

Intracerebral injection of ibotenate into mouse pups induced grey matter lesions and white matter cysts; co-administration of brain-derived neurotrophic factor (BDNF) produced a dose-dependent reduction in these lesions. In contrast, glial cell line-derived neurotrophic factor (GDNF) had no significant effect, whereas nerve growth factor (NGF) or interleukin-1β (IL-1β) resulted in dose-dependent exacerbation. The neuroprotective effects of BDNF were abolished by co-administration of anti-BDNF antibody or MEK inhibitors, or ABT-737, a BH3 mimetic and Bcl-2 antagonist. The actions of BDNF, GDNF and NGF were measured in a parallel in vitro study on the oxidative metabolism of mouse brain mitochondria. BDNF produced a concentration-dependent increase in the respiratory control index (RCI, a measure of respiratory coupling efficiency, ATP synthesis, and organelle integrity) when co-incubated with synaptosomes containing signal transduction pathways; but GDNF failed to modify RCI, and NGF had only weak effects. BDNF had no effect on pure mitochondria, and enhanced oxidation only when complex I substrates were used. The effect of BDNF was inhibited by anti-BDNF antibody, MEK inhibitors or ABT-737, and also by IL-1β, indicating that the mitochondrial effects are mediated via the same MEK-Bcl-2 pathway as the neuroprotection. The complex I inhibitor rotenone, a compound implicated in the aetiology of Parkinson's disease, inhibited both the in vitro mitochondrial and in vivo neuroprotective effects of BDNF. The ability of BDNF to modify brain metabolism and the efficiency of oxygen utilization via a MEK-Bcl-2 pathway may be an important component of the neuroprotective action observed with this neurotrophin.     

单用或联用UDP-糖、GDNF和美金刚对脑白质损伤大鼠长期预后的改善作用

目的 探讨单用和联用尿苷二磷酸葡萄糖(UDP-糖)、胶质细胞源性神经营养因子(GDNF)和美金刚对脑室周围白质软化(PVL)新生大鼠体格发育、学习记忆和肢体运动功能的远期影响. 方法 5日龄SD新生大鼠按照随机数字表法分为对照组、PVL组、UDP-糖组和UDP-糖+GDNF+美金刚组(简称三联药组).对照组大鼠仅游离右侧颈总动脉,不接扎和缺氧;PVL组大鼠结扎颈总动脉和缺氧;UDP-糖组大鼠在缺血缺氧后给予腹腔注射UDP-糖;三联药组大鼠在缺血缺氧后给予颅内注射GDNF,同时腹腔注射UDP-糖和美金刚.每组大鼠造模前后称重并记录睁眼日龄,在PVL造模后21d进行水迷宫和斜板测试,记录各组大鼠逃逸潜伏期、游泳距离及在不同倾斜角度下的斜板得分. 结果 PVL组在各时段的体质量及睁眼日龄均显著低于其他3组,四象限的平均逃逸潜伏期值和游泳距离数值均显著长于其他3组,在45°和50°斜板上的得分均显著低于其他3组,差异有统计学意义(P＜0.05);两个用药组间以及两个用药组分别和对照组间大鼠体质量、睁眼日龄、逃逸潜伏期值、游泳距离以及斜板评分的差异均无统计学意义(P＞0.05). 结论 单用UDP-糖或联用UDP-糖、GDNF和美金刚能明显改善脑白质损伤大鼠的长期预后,三联药组的改善作用略微更明显.     

PDGF-B及其受体蛋白在缺血大鼠脑组织中的表达

目的 探讨血小板源性生长因子B链(PDGF—B)及其受体PDGFR—β在缺血性脑损伤后濒危神经元存活和损伤修复中的作用。方法 采用线栓法制备大鼠大脑中动脉局灶性缺血模型，分别于缺血2h再灌注6h、24h、3d、7d、14d和21d处死，用免疫组化分别检测PDGF—B和PDGFR—β蛋白在脑缺血区及其周围的表达。结果 缺血再灌注后24h，PDGF—B和PDGFR—β在缺血区及其周围的神经元的表达开始增强，并分别于3d和7d出现第一个高峰，其中PDGFR—β的表达还可见于反应性胶质细胞；两者的第二个表达高峰出现在再灌注后14d，主要表达于梗死区增生的胶质细胞、新生血管和胶质疤痕周围的神经元。结论局灶性脑缺血后，PDGF—B及其受体蛋白在时间和空间上的一致性表达，说明它们对濒危神经元的存活、胶质疤痕形成和血管发生均有重要的作用。     

CXCR4 prevents dispersion of granule neuron precursors in the adult dentate gyrus

Neurogenesis in the adult dentate gyrus (DG) generates new granule neurons that differentiate in the inner one‐third of the granule cell layer (GCL). The migrating precursors of these neurons arise from neural stem cells (NSCs) in the subgranular zone (SGZ). Although it is established that pathological conditions, including epilepsy and stroke, cause dispersion of granule neuron precursors, little is known about the factors that regulate their normal placement. Based on the high expression of the chemokine CXCL12 in the adult GCL and its role in guiding neuronal migration in development, we addressed the function of the CXCL12 receptor CXCR4 in adult neurogenesis. Using transgenic reporter mice, we detected Cxcr4‐GFP expression in NSCs, neuronal‐committed progenitors, and immature neurons of adult and aged mice. Analyses of hippocampal NSC cultures and hippocampal tissue by immunoblot and immunohistochemistry provided evidence for CXCL12‐promoted phosphorylation/activation of CXCR4 receptors in NSCs in vivo and in vitro. Cxcr4 deletion in NSCs of the postnatal or mature DG using Cre technology reduced neurogenesis. Fifty days after Cxcr4 ablation in the mature DG, the SGZ showed a severe reduction of Sox2‐positive neural stem/early progenitor cells, NeuroD‐positive neuronal‐committed progenitors, and DCX‐positive immature neurons. Many immature neurons were ectopically placed in the hilus and inner molecular layer, and some developed an aberrant dendritic morphology. Only few misplaced cells survived permanently as ectopic neurons. Thus, CXCR4 signaling maintains the NSC pool in the DG and specifies the inner one‐third of the GCL as differentiation area for immature granule neurons. © 2013 Wiley Periodicals, Inc.     

补肾壮阳胶囊对精神分裂症模型大鼠海马胶质细胞源性神经营养因子表达的影响

目的 探讨补肾壮阳胶囊(WSKY)对地卓西平马来酸盐(MK801)建立的精神分裂症模型大鼠海马胶质细胞源性神经营养因子(GDNF)表达的影响.方法 将40只6周龄SD雄性大鼠随机分为3组:对照组(生理盐水腹腔注射+生理盐水灌胃)、模型组(M K801腹腔注射+生理盐水灌胃)及WSKY+MK801组(MK801腹腔注射+WSKY灌胃,而根据WSKY剂量的不同又分为3个亚组);各组相应处理两周后运用Western Blot和RT-PCR技术分别检测各组大鼠海马区GDNF蛋白及mRNA的表达.结果 与对照组相比较,模型组的GDNF蛋白及mRNA的表达下降,差异有统计学意义(P<0.05);而与模型组相比,WSKY+MK801组中较高剂量WSKY可致GDNF蛋白及其mRNA的表达增加,差异有统计学意义(P<0.05).结论 MK801可致大鼠海马GDNF表达减少,而补肾壮阳胶囊可上调大鼠海马GDNF的表达.     

Human adipose tissue‐derived mesenchymal stem cells improve cognitive function and physical activity in ageing mice

Brain ageing leads to atrophy and degeneration of the cholinergic nervous system, resulting in profound neurobehavioral and cognitive dysfunction from decreased acetylcholine biosynthesis and reduced secretion of growth and neurotrophic factors. Human adipose tissue‐derived mesenchymal stem cells (ADMSCs) were intravenously (1 × 10⁶ cells) or intracerebroventricularly (4 × 10⁵ cells) transplanted into the brains of 18‐month‐old mice once or four times at 2‐week intervals. Transplantation of ADMSCs improved both locomotor activity and cognitive function in the aged animals, in parallel with recovery of acetylcholine levels in brain tissues. Transplanted cells differentiated into neurons and, in part, into astrocytes and produced choline acetyltransferase proteins. Transplantation of ADMSCs restored microtubule‐associated protein 2 in brain tissue and enhanced Trk B expression and the concentrations of brain‐derived neurotrophic factor and nerve growth factor. These results indicate that human ADMSCs differentiate into neural cells in the brain microenvironment and can restore physical and cognitive functions of aged mice not only by increasing acetylcholine synthesis but also by restoring neuronal integrity that may be mediated by growth/neurotrophic factors. © 2013 Wiley Periodicals, Inc.     

Viral vector-mediated gene therapy for Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects 1% of the population above the age of 60. The cause of the disease remains unknown. The histopathological hallmarks of the disease are intracytoplasmic Lewy bodies and dopaminergic striatal insufficiency secondary to a loss of dopaminergic neurons in the substantia nigra pars compacta (SN). Pharmacological treatment options for PD are often limited by the ability of prodopaminergic drugs to function within the nigrostriatal system, without activating other dopaminergic, but non-nigrostriatal regions, of the CNS. Even if this obstacle is overcome, considerations regarding the chronic availability of the drug can limit drug utility. Gene delivery systems are ideal for delivering therapeutic molecules to site specific regions of the CNS. Via gene therapy, a piece or pieces of DNA placed into a carrying vector encoding for a substance of interest is introduced into cells. While there are many ways to apply this technology, this review will focus on in vivo gene therapy as it applies to Parkinson's disease. Using stereotaxic surgery, vectors can be introduced into specific target areas in the brain and deliver genes encoding for therapeutic molecules. By delivering genes using gene therapy approaches, a therapeutic molecule can be delivered chronically in a site-specific fashion, diminishing unwanted side effects and repeated interventions to obtain useful levels of the drug. Throughout this review, we discuss the potential for gene delivery aimed at enhancing dopamine production or providing neuroprotection for nigrostriatal neurons to serve as a therapeutic strategy for PD.     

Effects of neonatal stress on markers of synaptic plasticity in the hippocampus: Implications for spatial memory

Early stressful adverse situations may increase the vulnerability to cognitive deficits and psychiatric disorders, such as depression. Maternal separation (MS) has been used as an animal model to study changes in neurochemistry and behavior associated with exposure to early‐life stress. This study investigated the effects of neonatal stress (MS) on the expression of synaptic plasticity markers in the hippocampus and a purported relationship to cognitive processes. Spatial learning (Morris water maze) significantly increased the expression of total levels of the neural cell adhesion molecule (NCAM), as well as its three major isoforms (NCAM‐120, ‐140, and ‐180) both in the control and MS groups. Interestingly, these increases in NCAM expression after learning were lower in MS animals when compared with control rats. MS induced a significant decrease in total levels of NCAM, and specifically, in the NCAM‐140 isoform expression. In the hippocampus of MS rats there was a significant decrease in brain‐derived neurotrophic factor and synaptophysin mRNA densities. Cell proliferation, measured as BrdU‐positive cells, was also decreased in the dentate gyrus of MS rats. Altogether these results suggest that MS can alter normal brain development, providing a potential mechanism by which early environmental stressors may influence vulnerability to show cognitive impairments later in life. © 2009 Wiley‐Liss, Inc.