脑血疏口服液灌胃对帕金森病模型大鼠黑质内神经炎症反应的影响

目的:研究脑血疏口服液对帕金森病(PD)模型大鼠黑质内神经炎症的抑制作用,以及对黑质多巴胺(DA)能神经元的保护作用。方法:应用立体定向注射技术,向大鼠脑右侧纹状体内注射6-羟多巴胺制备PD模型。将PD模型大鼠随机分为PD组、雷沙吉兰组和脑血疏口服液高、中、低剂量干预组,每组10只;另选10只正常大鼠作为对照组。采用免疫组织化学法检测各组大鼠黑质DA能神经元(酪氨酸羟化酶(TH)阳性)、小胶质细胞(CD11b阳性)、星形胶质细胞(GFAP阳性)形态变化。Western Blot法检测中脑黑质环氧化酶-2(COX-2)和肿瘤坏死因子-α(TNF-α)的变化。结果:大鼠行为学检测和黑质TH免疫组织化学染色显示,中剂量组的干预效果最好。免疫组织化学显示,与对照组相比,PD组的星形胶质细胞、小胶质细胞、TNF-α阳性细胞和COX-2阳性细胞均明显增加,TH阳性细胞数量明显减少,经中剂量的脑血疏口服液干预后,两种胶质细胞、TNF-α和COX-2阳性细胞数量均减少,TH阳性细胞增多。Western Blot显示,与PD组比较,中剂量组和雷沙吉兰组GFAP、CD11b、TNF-α和COX-2蛋白表达量显著减少(P0.05),而中剂量组与雷沙吉兰组比较上述蛋白表达均无显著差异(P0.05)。结论:脑血疏口服液可能通过抑制PD大鼠黑质胶质细胞的异常激活,减少炎性因子分泌而发挥神经保护作用。     

帕金森病大鼠黑质小胶质细胞及星形胶质细胞的变化

目的探讨帕金森病(PD)发病中黑质小胶质细胞和星形胶质细胞的变化。方法采用立体定向术将神经毒素6-羟基多巴胺(6-OHDA)注入大鼠右侧黑质和内侧前脑束内,制备大鼠PD模型。将制模成功的16只PD大鼠随机分为2周和8周模型组,另6只正常大鼠作为对照组。观察各组大鼠黑质致密带内多巴胺(DA)能神经元、OX-42(小胶质细胞的特异性标志物)及神经胶质纤维酸性蛋白(GFAP,星形胶质细胞的特异性标志物)阳性细胞的分布和形态变化。结果 2周和8周模型组损毁侧黑质致密部DA能神经元较健侧显著减少(P0.01),损毁侧OX-42阳性细胞的数量较健侧明显增加(P0.01),形态呈"阿米巴状"。损毁侧GFAP阳性细胞数量较健侧明显增加(P0.01),突起变短,染色加深。2周模型组和8周模型组DA能神经元及两种胶质细胞的变化情况相似。结论 PD大鼠模型中存在着小胶质细胞和星形胶质细胞的激活,且两种胶质细胞的活化程度在PD发病过程中的不同时间无明显差别。     

香椿子多酚对6-OHDA所致帕金森病大鼠模型的抗炎和神经保护作用

目的:观察香椿子多酚(polyphenols from toona sinensis seeds,PTSS)抑制神经炎症反应,对黑质多巴胺能神经元的保护作用。方法:脑立体定向注射6-羟多巴胺(6-OHDA)至右侧纹状体,制备帕金森病(Parkinson’s disease,PD)大鼠模型。将成模大鼠随机分为模型组和PTSS组,另10只正常大鼠设为对照组,PTSS组每日PTSS灌胃2 ml,另外两组大鼠等体积量生理盐水灌胃,1/d次,连续30 d。免疫组织化学法观测大鼠黑质多巴胺能(酪氨酸羟化酶TH阳性)神经元、星形胶质细胞(GFAP阳性)、小胶质细胞(CD11b阳性)形态和数量变化。RT-PCR和Western Blot分别检测黑质肿瘤坏死因子(TNF-α)和环氧化酶-2(COX-2)在mRNA和蛋白水平上的变化。结果:免疫组织化学结果显示,与对照组比较,模型组和PTSS组大鼠黑质TH阳性细胞数量显著下降、黑质CD11b和GFAP免疫反应阳性细胞数量明显增多(P0.05)。中脑黑质TNF-α和COX-2蛋白含量显著升高;RT-PCR检测TNF-αmRNA和COX-2 mRNA表达量的结果与Western Blot一致。与模型组比较,PTSS组大鼠旋转圈数明显减少(P0.05)、黑质TH阳性细胞数量显著增多,CD11b、GFAP阳性细胞数量明显下降,TNF-α和COX-2阳性表达光密度值降低;黑质中TNF-α和COX-2蛋白含量及其mRNA表达量显著下降。结论:PTSS能够抑制胶质细胞活化,减轻神经炎症,有效保护黑质DA能神经元。     

帕金森病大鼠黑质区神经干细胞分化的观察

目的:探讨帕金森病(Parkinson's disease,PD)大鼠中脑黑质区神经干细胞(NSCs)的分化情况.方法:将6-OHDA注入纹状体内制作PD大鼠模型.随机将成功模型分为3 d、5 d、7 d、14 d、28 d组,每组6只;另设假手术及正常对照组各3只.向成功模型鼠腹腔注射5-溴脱氧尿苷(Brdu).用Brdu/NeuN、Brdu/GFAP、Brdu/TH免疫双标组织化学方法检测黑质区内源性NSCs向神经元、神经胶质细胞和多巴胺(DA)能神经元的分化情况.结果:PD模型7 d组,在黑质区Brdu /GFAP 、Brdu /NeuN 细胞开始出现,14 d组双标的阳性细胞数量逐渐增加,28 d达到高峰,14 d、28 d组与其它组比较差异显著(P＜0.05).在这些双标细胞中,Brdu /GFAP 细胞数量较多,Brdu /NeuN 细胞数量较少(P＜0.05),未发现Brdu /TH 细胞.结论:PD大鼠模型黑质区NSCs多数分化为神经胶质细胞,少数分化为神经元,在没有诱导和干预下,未见有向DA能神经元分化.     

血管活性肠肽对帕金森病大鼠黑质胶质细胞活化及相关炎性因子释放的影响

目的探讨血管活性肠肽(VIP)对帕金森病(PD)大鼠模型中脑黑质胶质细胞活化及相关炎性因子表达的影响。方法将6-羟多巴胺(6-OHDA)定向注入大鼠右侧纹状体制备PD模型。32只制备成功的PD大鼠随机分为VIP组和模型组,VIP组大鼠腹腔注射VIP 1ml(20μg/L),另10只正常大鼠为对照组。分别采用免疫组织化学、Western blotting、RT-PCR方法观察大鼠中脑黑质多巴胺(DA)能神经元、小胶质细胞、星形胶质细胞的数量和形态变化以及肿瘤坏死因子α(TNF-α)和环氧化酶2(COX-2)的表达变化。结果模型组大鼠黑质损毁侧小胶质细胞即白细胞分化抗原11b(CD11b)阳性细胞,数量较对照组明显增加(P0.05)并呈阿米巴样改变,星形胶质细胞(GFAP阳性细胞)数量明显增加(P0.05),炎性因子表达水平也明显上升(P0.05),DA能神经元数量较对照组明显下降(P0.05);与模型组相比,VIP组大鼠损毁侧黑质小胶质细胞和星形胶质细胞数量明显下降(P0.05),炎性因子表达水平显著降低(P0.05),DA能神经元数量较模型组增加(P0.05)。结论 VIP对帕金森病大鼠黑质小胶质细胞和星形胶质细胞的活化具有抑制作用,并可减少相关炎症因子的表达,从而保护黑质DA能神经元。     

硫辛酸对帕金森模型大鼠黑质内神经胶质细胞及多巴胺能神经元的影响

目的:探讨硫辛酸(LA)对帕金森病(PD)模型大鼠黑质内星形胶质细胞胶质纤维酸性蛋白(GFAP)、小胶质细胞离子钙接头蛋白(Iba-l)、酪氨酸羟化酶(TH)表达的影响。方法:130只雄性SD大鼠随机分为对照组(颅内注射生理盐水)30只、模型组(颅内注射6-OHDA)100只。30只对照组大鼠术后4周再随机取20只作为假手术组;100只模型组大鼠4周后随机取80只成功模型再随机分为PD模型组和硫辛酸干预低、中、高剂量组,每组20只。模型组采用立体定位仪定向注射6-OHDA。对照组定向注射等体积的生理盐水。硫辛酸低、中、高剂量组于PD模型大鼠成功术后4周分别每日腹腔注射15、30、60 mg/kg,连续注射14 d。干预结束后取各组大鼠右侧中脑黑质采用Western Blot方法检测GFAP和Iba-l的表达,采用免疫组化方法检测黑质内TH的表达情况。结果:(1)与假手术组比较,PD模型组及硫辛酸干预低、中、高剂量组大鼠黑质内GFAP及Iba-1的表达均明显有所增加(P<0.05),但TH阳性细胞数则明显有所减少(P<0.01);(2)与PD模型组比较,硫辛酸干预低、中、高剂量组大鼠黑质内GFAP及Iba-1表达均明显减少(P<0.05),而TH阳性细胞数则明显增加(P<0.05);(3)与硫辛酸干预低剂量组比较,硫辛酸干预中、高剂量组大鼠黑质内GFAP及Iba-1表达均明显减少(P<0.05),而TH阳性细胞数则明显有所增加(P<0.01);(4)硫辛酸干预中、高剂量组间大鼠黑质内GFAP及Iba-1的表达虽无显著差异(P>0.05),但TH阳性细胞数则明显有所增加(P<0.05)。结论:硫辛酸通过抑制帕金森病模型大鼠黑质内星形胶质细胞和小胶质细胞的过度表达,保护多巴胺能神经元,该结果可为帕金森病的治疗提供新的思路。     

香椿子多酚通过抑制p38MAPK信号通路减轻帕金森病大鼠的神经炎症反应

目的探讨香椿子多酚(PTSS)对帕金森病(PD)大鼠神经炎症的抑制作用及机制。方法成年雄性SD大鼠单侧纹状体内注射6-羟多巴胺(6-OHDA)造模。造模成功大鼠随机分为模型组、PTSS处理组,另设一组正常大鼠为对照组,每组10只。30 d后,采用阿朴吗啡(APO)腹腔注射诱导大鼠的旋转行为,检测各组大鼠的行为改变。免疫组织化学染色法观测各组大鼠黑质酪氨酸羟化酶(TH)阳性的多巴胺(DA)能神经元、钙离子结合接头蛋白分子1(Iba1)阳性的小胶质细胞、胶质原纤维酸性蛋白(GFAP)阳性的星形胶质细胞形态和数量变化;免疫组织化学染色法检测黑质诱导型一氧化氮合酶(iNOS)、核因子κBp65(NF-κBp65)、p38丝裂原活化蛋白激酶(p38MAPK)和磷酸化的p38MAPK(p-p38MAPK)的表达; Western blot法检测大鼠黑质TH、GFAP、p38MAPK、p-p38MAPK蛋白水平。结果 PTSS处理组大鼠的旋转圈数较模型组明显减少。模型组大鼠损毁侧黑质TH阳性细胞较对照组显著减少, PTSS处理后, TH阳性细胞数量以及蛋白表达明显增加。与对照组相比,模型组大鼠损毁侧黑质Iba1、GFAP、iNOS、NF-κB、p38MAPK和p-p38MAPK蛋白含量显著增加。PTSS处理后,上述蛋白的表达均明显减弱,蛋白含量显著降低。结论 PTSS通过抑制p38MAPK信号通路,减少炎症因子的表达,对PD大鼠DA能神经元起保护作用。     

尼古丁对PD大鼠黑质多巴胺能神经元变性的影响

目的 探讨尼古丁对帕金森病(PD)大鼠黑质多巴胺能神经元变性的影响及其机制. 方法 45只大鼠随机分为PBS对照组(CON)、生理盐水+ 脂多糖(NS)组、尼古丁+脂多糖(NIC)组,每组15只.黑质内立体定向注射脂多糖(LPS)或PBS后24h,免疫印迹法检测黑质诱导性一氧化氮合酶(iNOS)蛋白表达变化;黑质注射药物后14d,采用免疫组织化学法观察大鼠黑质酪氨酸羟化酶(TH)阳性神经元数量及OX-42阳性细胞形态学变化,RT-PCR及免疫印迹检测黑质TH mRNA及TH蛋白的表达水平. 结果 与CON组相比,NS组大鼠黑质iNOS表达明显增多,TH阳性神经元、TH mRNA及TH蛋白明显减少,小胶质细胞大多呈胞体大突起短粗的形态;NIC组黑质iNOS表达明显少于NS组,黑质TH阳性神经元、TH mRNA及TH蛋白表达较NS组明显增多,大部分小胶质细胞呈胞体小,突起细长的形态. 结论 尼古丁可以减轻LPS介导的多巴胺能神经元变性,对多巴胺能神经元有保护作用,其保护机制与抑制小胶质细胞激活、减少iNOS的表达有关.     

帕金森病模型大鼠黑质内神经祖细胞的增殖

目的研究成年大鼠帕金森病（PD）时,黑质内是否存在神经祖细胞,并进一步观察其增殖和分化的情况.方法成年大鼠纹状体内立体定位注射6-羟多巴胺（6-OHDA）,并作行为学分析,筛选PD动物模型.取不同存活时间鼠脑黑质节段,用免疫组织化学染色方法,以抗巢蛋白（Nestin）抗体、抗增殖细胞核抗原（PCNA）抗体、抗Ⅲ型β-微管蛋白（Tuj1）抗体、抗酪氨酸羟化酶（TH）抗体分别显示神经祖细胞、分裂细胞、神经元前体细胞和多巴胺（DA）能神经元.光镜观察并细胞计数,统计学分析.结果PD模型大鼠右侧黑质内可见：1.Nestin反应阳性细胞：注射6-OHDA后第10 d,黑质致密部可见少量Nestin阳性细胞;第14 d时,出现大量Nestin阳性细胞;第17 d时开始减少;第21 d几乎检测不到.2.抗PCNA反应阳性细胞：注射6-OHDA后第7 d即可检测到较弱的PCNA阳性细胞;第14 d出现大量PCNA阳性细胞;至21 d开始减少、减弱;28 d时则检测到少量阳性细胞.3.抗Tuj1反应阳性细胞：注射后第10 d,开始出现少量Tuj1阳性细胞;第14 d出现大量Tuj1阳性细胞;第17 d开始减少,第21 d几乎检测不到.4.抗TH反应阳性神经元：注射6-OHDA后第7 d,黑质致密部抗TH反应阳性神经元数量显著少于对照组,且随注射时间延长而逐渐下降.结论成年大鼠纹状体内注射6-OHDA致黑质多巴胺能神经元变性、死亡,能诱导黑质内神经祖细胞在一段时期内大量增殖并向神经细胞方向分化（不包括多巴胺能神经元）.     

Sertoli细胞对大鼠大脑皮质神经前体细胞的诱导分化作用

目的:研究Sertoli细胞对体外培养大鼠皮质神经前体细胞生长发育的促进作用,及向多巴胺能神经元分化的诱导作用.方法:将大鼠Sertoli细胞与14 d大鼠皮质神经前体细胞体外共培养,免疫细胞化学检测神经干细胞标记物巢蛋白,神经元、星形胶质细胞和小胶质细胞标记物βⅢ-微管蛋白(βⅢ-tubulin)、胶质纤维酸性蛋白(GFAP)和半乳糖脑苷脂(GalC),及多巴胺能神经元标记物酪氨酸羟化酶(TH)的表达情况.结果:随着共培养时间的延长,神经前体细胞中GFAP阳性细胞数量逐渐减少,而β-Ⅲ tubulin 阳性细胞数增多,并出现TH阳性神经元.结论:Sertoli细胞抑制体外培养的大鼠皮质神经前体细胞的生长,但具有显著促神经元分化作用,并能够诱导与其共培养的大鼠皮质神经前体细胞分化为多巴胺能神经元.     

益精养血方对帕金森病大鼠多巴胺能神经元Bcl-2及caspase-3表达的影响

为了观察益精养血方对帕金森病(Parkinson’sdisease,PD)大鼠多巴胺能神经元Bcl-2及caspase-3表达的影响,本研究采用6-羟多巴胺注入右侧黑质制备的PD模型大鼠,实验分为模型组、实验(益精养血方)组和正常组。正常组和模型组大鼠用生理盐水灌胃,实验组大鼠用益精养血方灌胃,各30d。灌胃结束两周后进行旋转行为学检测,并用免疫荧光组织化学方法观察黑质酪氨酸羟化酶(TH)阳性神经元及神经纤维的变化,用免疫组织化学方法观测黑质神经元Bcl-2、caspase-3的表达。结果显示:(1)实验组大鼠的旋转圈数比治疗前明显减少(P<0.05);(2)实验组损毁侧与健侧黑质TH阳性神经元数量百分比和网状部TH阳性纤维面积百分比较模型组显著提高(P<0.05);(3)实验组损毁侧黑质神经元caspase-3表达的OD值比模型组显著降低(P<0.05),而Bcl-2的表达与caspase-3相反。以上结果提示益精养血方可使帕金森病大鼠黑质内多巴胺能神经元Bcl-2的表达升高,caspase-3的表达降低,进而明显抑制神经细胞的凋亡。     

Intrastriatal administration of erythropoietin protects dopaminergic neurons and improves neurobehavioral outcome in a rat model of Parkinson's disease

Erythropoietin (EPO), a hematopoietic cytokine, has recently been demonstrated to protect nigral dopaminergic neurons in a mouse model of Parkinson's disease (PD). In the present study, we tested the hypothesis that recombinant human erythropoietin (rhEPO) could protect dopaminergic neurons and improve neurobehavioral outcome in a rat model of PD. rhEPO (20 units in 2 microl of vehicle) was stereotaxically injected into one side of the striatum. 6-hydroxydopamine (6-OHDA) was injected into the same side 1 day later. Another group of rats received rhEPO (5000 u/kg, i.p.) daily for 8 days, and unilateral injection of 6-OHDA in the striatum 3 days after systemic administration of rhEPO. We observed that intrastriatal administration, but not systemic administration of rhEPO significantly reduced the degree of rotational asymmetry. The rhEPO-treated rats also showed an improvement in skilled forelimb use when compared with control rats. The number of tyrosine hydroxylase (TH)-immunoreactive (IR) neurons in the ipsilateral substantia nigra (SN) was significantly larger in intrastriatal rhEPO-treated rats than that in control rats. TH-IR fibers in the 6-OHDA-lesioned striatum were also increased in the intrastriatal rhEPO-treated rats when compared with control rats. In addition, there were lower levels of expression of major histocompatibility complex (MHC) class II antigens and a smaller number of activated microglia in the ipsilateral SN in intrastriatal rhEPO-treated rats than that in control rats at 2 weeks, suggesting that intrastriatal injection of rhEPO attenuated 6-OHDA-induced inflammation in the ipsilateral SN. Our results suggest that intrastriatal administration of rhEPO can protect nigral dopaminergic neurons from cell death induced by 6-OHDA and improve neurobehavioral outcome in a rat model of PD. Anti-inflammation may be one of mechanisms responsible for rhEPO neuroprotection.     

The effect of intrastriatal single injection of GDNF on the nigrostriatal dopaminergic system in hemiparkinsonian rats: behavioral and histological studies using two different dosages

Glial cell line-derived neurotrophic factor (GDNF) is a member of the transforming growth factor-beta superfamily and acts as a neurotrophic factor for the nigrostriatal dopamine (DA) system. Although previous studies have shown that pretreatment with GDNF could prevent degenerative changes of nigrostriatal DA system by DA neurotoxin 6-hydroxydopamine (6-OHDA), it is not really known whether GDNF can induce recovery of nigrostriatal DA system after partial lesioning by 6-OHDA. Substantia nigra has been commonly chosen as injection site for GDNF but a limited number of studies have used striatum as injection site where neural transplantation is commonly performed. Unilateral intrastriatal administration of 6-OHDA was performed in Sprague-Dawley rats to create partial lesion of the nigrostriatal DA system. These hemiparkinsonian model rats received a 10- or 100-microg single injection of human recombinant GDNF into the same portion of the striatum 4 weeks after 6-OHDA treatment. Both animals that received a 10- or 100-microg single injection of GDNF showed decreased apomorphine-induced rotation at 2 weeks after injection. More potent and prolonged functional recovery was observed in animals receiving 100 microg of GDNF than in those receiving 10 microg of GDNF. Tyrosine hydroxylase (TH) immunocytochemistry revealed that TH positive DA fiber density in the striatum and the number of DA cell bodies in the substantia nigra were greater in animals receiving 10 or 100 microg of GDNF than those receiving saline. These immunocytochemical results have also shown that 100 microg of GDNF was more potent than 10 microg of GDNF. These morphological and functional results indicate that GDNF treatment 4 weeks after 6-OHDA lesioning could induce recovery of nigrostriatal DA system. Striatum was a good site for GDNF administration for hemiparkinsonian rats and a single injection of 100 microg of GDNF was more potent than 10 microg of GDNF.     

GDNF reduces oxidative stress in a 6-hydroxydopamine model of Parkinson's disease

Many current theories of Parkinson's disease (PD) suggest that oxidative stress is involved in the neurodegenerative process. Potential neuroprotective agents could protect neurons through inherent antioxidant properties or through the upregulation of the brain's antioxidant defenses. Glial cell line-derived neurotrophic factor (GDNF) has been shown to protect and restore dopamine neurons in experimental models of PD and to improve motor function in human patients. This study was designed to investigate GDNF's effect on oxidative stress in a model of PD. GDNF or vehicle was injected into the right striatum of male Fischer-344 rats. Three days later 6-OHDA or saline was injected into the same striatum. The striatum and substantia nigra from both sides of the brain were removed 24h after 6-OHDA or saline injection and analyzed for the oxidative stress markers protein carbonyls and 4-hydroxynonenal. Both markers were significantly reduced in GDNF+6-OHDA treated animals compared to vehicle+6-OHDA treated animals. In addition, in animals allowed to recover for 3.5-4 weeks after the 6-OHDA administration, the GDNF led to significant protection against loss of striatal and nigral tissue levels of dopamine. These results suggest that the protective effects of GDNF against 6-OHDA involve a reduction in oxidative stress.     

6-OHDA所致PD大鼠模型黑质多巴胺能神经元与胶质细胞的变化

目的 应用6-羟多巴(6.OHDA)建立帕金森病(PD)大鼠模型。方法将6-OHDA立体注入大鼠前脑内侧束,应用免疫组织化学法检测6-OHDA注射后第3、7及14天后多巴胺能神经元、小胶质细胞与星形胶质细胞数量及形态的变化。用显微镜专业摄像头采集图像,计算机图像分析软件测量平均灰度值。结果 损伤侧与对侧相比,TH阳性多巴胺能神经元数量减少,损伤侧平均灰度值增加;小胶质细胞与星形胶质细胞显著增生,二者损伤侧的平均灰度值下降,经配对t检验,各组内比较差异均具有显著性意义(P<0.01);增生活化的小胶质细胞与星形胶质细胞形态发生明显的改变。结论 6-OHDA能成功建立PD大鼠模型。     

6-羟多巴诱导大鼠黑质的持续胶质细胞反应

本研究将40μg6- 羟多巴注射到SD大鼠一侧纹状体制作Parkinson病动物模型,研究黑质反应性神经胶质增生在Par kinson病发病过程中的可能作用。筛选成功的模型大鼠,术后12周处死。应用免疫荧光双标记法检测模型大鼠黑质胶质细胞对多巴胺能神经元损伤的反应。结果显示:在注射后12周,损伤侧黑质仍然存在明显的星形胶质细胞反应和小胶质细胞激活。此外,小胶质小结和淋巴细胞浸润的存在提示在注射后12周的注射侧黑质内依然有多巴胺能神经元死亡。结论: 6 -羟多巴对大鼠黑质多巴胺能神经元的急性损伤可以通过胶质细胞反应从而对多巴胺能神经元产生长期的毒性作用。     

Intranigral ventral mesencephalic grafts and nigrostriatal injections of glial cell line-derived neurotrophic factor restore dopamine release in the striatum of 6-hydroxydopamine-lesioned rats

We have previously reported that grafting of fetal ventral mesencephalic (VM) tissue to the nigral region of unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rats, in conjunction with glial cell line-derived neurotrophic factor (GDNF) injection between nigra and striatum, restores nigrostriatal tyrosine hydroxylase (TH) immunoreactivity. In this study, we investigated the electrochemical indices of dopamine (DA) release in these grafted animals in the striatum and nigra. Adult Sprague-Dawley rats were anesthetized and unilaterally injected with 6-OHDA into the medial forebrain bundle. The completeness of lesions was tested by measuring methamphetamine-induced rotations. One to two months after 6-OHDA administration, fetal VM tissues were grafted in the lesioned nigral area followed by injection of GDNF, brain-derived neurotrophic factor (BDNF), or phosphate-buffered saline (PBS), along a tract from nigra to striatum. Animals receiving transplantation and GDNF, but not BDNF or PBS, injection showed a significant decrease in rotation 1–3 months after grafting. High-speed chronoamperometric recording techniques, using Nafion-coated carbon fiber electrodes, were used to evaluate DA overflow in the striatum. We found that 6-OHDA lesions resulted in a loss of KCl-induced DA overflow in the urethane-anesthetized rats. Three months after GDNF-bridged grafting, application of KCl elicited DA release both in nigra and striatum. The KCl-evoked DA release area was limited to the GDNF-bridging tract in the striatum. On the other hand, KCl did not induce DA release in the BDNF- or PBS-bridged grafts. Immunocytochemical studies indicated that TH-positive neurons and fibers were found in the nigra and striatum after GDNF-bridged grafting. Taken together, our data suggest that fetal nigral transplantation and GDNF injection may restore the nigrostriatal DA pathway and DA release in these hemiparkinsonian animals and support the hypothesis of trophic activity of GDNF on fiber outgrowth from midbrain DA neurons. Received: 8 August 1997 / Accepted: 9 August 1997