Protective action of recombinant neurturin on dopaminergic neurons in substantia nigra in a rhesus monkey model of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by muscular trembling palsy due to lack of dopamine (DA) in the substantia nigra-striatum (nigrostriatal) system resulting from the degeneration and necrosis of dopaminergic neurons. No effective cure has been found. Neurturin (NTN) has been demonstrated to act specifically on midbrain (mesencephalic) dopaminergic neurons with protective actions specifically. In the present study, we induced rhesus monkey model of Parkinson's disease by injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Rhesus monkeys were randomly divided into a PD model group, NTN treatment group and normal control groups. In the NTN treatment group, 1 mg of E. coli-derived recombinant human NTN was injected into the cerebral ventricles 48 h before the injection of MPTP. Results indicated that Rhesus monkeys in the PD model group acquired PD symptoms that increasingly aggravated over time, while monkeys treated with NTN had less apparent or no symptoms. Using fluorospectrophotometry, the dopamine (DA), 5, 5-hydroxytrytamine (5-HT) and the 5-hydroxyindoleacetic acid (5-HIAA) contents of DA, 5-HT and 5-HIAA in substantia nigra, putamen and caudate nucleus in monkeys from the model group was found to be significantly lower than in the normal control group. While no significant differences were found between monkeys treated with NTN and normal control groups, the contents of DA, 5-HT and 5-HIAA in the NTN treatment group were higher than those observed in the PD model group. A dramatic loss of neurons in the substantia nigra in monkeys in the PD model group was observed by light microscopy, while no obvious loss was observed in the NTN treatment group in which the numbers of neurons were similar to those in normal controls. These results indicate that recombinant human NTN can prevent PD symptoms as well as protect dopaminergic neurons and preserve DA content in midbrain substantia nigra in rhesus monkeys exposed to MPTP.     

AAV2-mediated delivery of human neurturin to the rat nigrostriatal system: long-term efficacy and tolerability of CERE-120 for Parkinson's disease

Neurturin (NTN) is a neurotrophic factor with known potential to protect and restore the function of dopaminergic substantia nigra neurons whose degeneration has been most closely linked to the major motor deficits in Parkinson's disease (PD). CERE-120, an adeno-associated virus serotype 2 (AAV2)-based gene delivery vector encoding human NTN, is being developed as a potential therapeutic for PD. In a series of preclinical studies reported herein, CERE-120 delivery to the striatum produced a dose-related neuroprotection of nigrostriatal neurons in the rat 6-hydroxydopamine (6-OHDA) lesion model. Long-lasting efficacy of CERE-120 was evidenced by substantia nigra cell protection, preserved fiber innervation of the striatum, and behavioral recovery for at least 6 months. In addition, striatal infusion of CERE-120 was found to have a safety and tolerability profile devoid of side effects or toxicological responses, for at least 12 months post-treatment, even at dose multiples 125 times that of the lowest efficacious dose tested. These results support the ongoing CERE-120 clinical program in PD patients.     

Zuckerkandl's organ improves long-term survival and function of neural stem cell derived dopaminergic neurons in Parkinsonian rats

Transplantation of neural stem cells (NSC) derived dopamine (DA) neurons has emerged as an alternative approach to fetal neural cell transplantation in Parkinson's disease (PD). However, similar to fetal neural cell, survival of these neurons following transplantation is also limited due to limited striatal reinnervation (graft with dense neuronal core), limited host-graft interaction, poor axonal outgrowth, lack of continuous neurotrophic factors supply and principally an absence of cell adhesion molecules mediated appropriate developmental cues. In the present study, an attempt has been made to increase survival and function of NSC derived DA neurons, by co-grafting with Zuckerkandl's organ (a paraneural organ that expresses neurotrophic factors as well as cell adhesion molecules); to provide continuous NTF support and developmental cues to transplanted DA neurons in the rat model of PD. 24 weeks post transplantation, a significant number of surviving functional NSC derived DA neurons were observed in the co-transplanted group as evident by an increase in the number of tyrosine hydroxylase immunoreactive (TH-IR) neurons, TH-IR fiber density, TH-mRNA expression and TH-protein level at the transplantation site (striatum). Significant behavioral recovery (amphetamine induced stereotypy and locomotor activity) and neurochemical recovery (DA-D2 receptor binding and DA and DOPAC levels at the transplant site) were also observed in the NSC+ZKO co-transplanted group as compared to the NSC or ZKO alone transplanted group. In vivo results were further substantiated by in vitro studies, which suggest that ZKO increases the NSC derived DA neuronal survival, differentiation, DA release and neurite outgrowth as well as protects against 6-OHDA toxicity in co-culture condition. The present study suggests that long-term and continuous NTF support provided by ZKO to the transplanted NSC derived DA neurons, helped in their better survival, axonal arborization and integration with host cells, leading to long-term functional restoration in the rat model of PD.     

尼古丁对帕金森病大鼠纹状体GDNF和多巴胺含量的影响

目的 研究尼古丁对帕金森病（PD）大鼠纹状体脑胶质细胞源性神经营养因子(GDNF)和多巴胺（DA）含量的影响。方法 将6－羟多巴胺（6－OHDA）立体定向注射到大鼠右侧中脑腹侧背盖部（VTA）和黑质致密部（SNpc)，建立PD大鼠模型。采用生化、免疫组织化学方法观察不同剂量尼古丁对PD大鼠的作用，检测纹状体GDNF表达及DA含量的变化。结果 造模前及造模后皮下注射尼古丁的PD大鼠，纹状体GDNF表达及DA含量较PD组有明显改善（P＜0．05）。结论 尼古丁可减轻6－OHDA对黑质DA能神经元的损伤，对PD大鼠具有保护作用。     

Patterns of developmental mRNA expression of neurturin and GFRalpha2 in the rat striatum and substantia nigra do not suggest a role in the regulation of natural cell death in dopamine neurons

We examined the mRNA expression of neurturin (NTN) and its receptor GFRalpha2 in rat substantia nigra (SN) and striatum by northern analysis at ages ranging from postnatal day (PND) 2 to adult. NTN mRNA expression is developmentally regulated in striatum with a peak at PND10, but its expression in striatum is low, and less than that of SN. In SN, there is no developmental regulation. GFRalpha2 was expressed most highly during the first two postnatal weeks. Like NTN, GFRalpha2 mRNA was also more abundant in SN, at both PND2 and 14. Our results show that NTN expression is relatively low in the striatum, the target of dopamine (DA) neurons, and there is no apparent pattern of developmental regulation in SN. Thus these studies are not strongly supportive of a role for NTN in regulating natural cell death (NCD) in DA neurons, either as a target-derived or as a local paracrine factor.     

Efficient in vivo protection of nigral dopaminergic neurons by lentiviral gene transfer of a modified Neurturin construct

Protein injection studies of the glial cell line derived neurotrophic factor (GDNF) family member Neurturin (NTN) have demonstrated neuroprotective effects on dopaminergic (DA) neurons, which are selectively lost during Parkinson's disease (PD). However, unlike GDNF, NTN has not previously been applied in PD models using an in vivo gene therapy approach. Difficulties with lentiviral gene delivery of wild type (wt) NTN led us to examine the role of the pre-pro-sequence, and to evaluate different NTN constructs in order to optimize gene therapy with NTN. Results from transfected cultured cells showed that wt NTN was poorly processed, and secreted as a pro-form. A similarly poor processing was found with a chimeric protein consisting of the pre-pro-part from GDNF and mature NTN. Moreover, we found that the biological activity of pro-NTN differs from mature NTN, as pro-NTN did not form a signaling complex with the tyrosine kinase receptor Ret and GFRalpha2 or GFRalpha1. Deletion of the pro-region resulted in significantly higher secretion of active NTN, which was further increased when substituting the wt NTN signal peptide with the immunoglobulin heavy-chain signal peptide (IgSP). The enhanced secretion of active mature NTN using the IgSP-NTN construct was reproduced in vivo in lentiviral-transduced rat striatal cells and, unlike wt NTN, enabled efficient neuroprotection of lesioned nigral DA neurons, similar to GDNF. An in vivo gene therapy approach with a modified NTN construct is therefore a possible treatment option for Parkinson's disease that should be further explored.     

Transplantation of neural stem cells co-transfected with Nurr1 and Brn4 for treatment of Parkinsonian rats

Neural stem cells (NSCs) tranplantation has great potential for the treatment of neurodegenerative disease such as Parkinson's disease (PD). However, the usage of NSCs is limited because the differentiation of NSCs into specific dopaminergic neurons has proven difficult. We have recently demonstrated that transgenic expression of Nurr1 could induce the differentiation of NSCs into tyrosine hydroxylase (TH) immunoreactive dopaminergic neurons, and forced co-expression of Nurr1 with Brn4 caused a dramatic increase in morphological and phenotypical maturity of these neurons. In this study, we investigated the effect of transplanted NSCs in PD model rats. The results showed that overexpression of Nurr1 promoted NSCs to differentiate into dopaminergic neurons in vivo, increased the level of dopamine (DA) neurotransmitter in the striatum, resulting in behavioral improvement of PD rats. Importantly, co-expression of Nurr1 and Brn4 in NSCs significantly increased the maturity and viability of dopaminergic neurons, further raised the DA amount in the striatum and reversed the behavioral deficit of the PD rats. Our findings provide a new potential and strategy for the use of NSCs in cell replacement therapy for PD.     

帕金森病模型大鼠黑质多巴胺能神经元的氧化应激研究

目的　探索帕金森病模型大鼠黑质多巴胺能神经元的氧化应激发病机制。方法　通过立体定位仪 ,将 6-OHDA注入大鼠一侧纹状体内制备 PD模型 ,2周后观察动物的行为学改变 ,2个月后观察黑质纹状体等的病理形态学变化 ,检测模型组、假手术组和正常对照组的超氧化物歧化酶 (SOD)的活性 ,丙二醛 (MDA)、一氧化氮(NO)代谢产物 (NO x)的含量的变化。结果　成功 PD模型鼠有 2 2只。光镜下 HE染色示模型组右侧黑质的多巴胺神经元受损 ,数目减少。模型组右侧黑质的 SOD的含量下降 ,MDA及 NO x含量明显升高 ,与左侧、假手术组及正常对照组相比有显著差异 (P>0 .0 5)。结论　 6-OHDA纹状体内双靶点注射法是一种有效的制备 PD模型的方法。帕金森病大鼠模型黑质内 SOD活性下降 ,MDA、NO x含量升高 ,氧化应激在 PD的发病中起重要的作用     

胚胎多巴胺神经元移植治疗帕金森病的实验研究

目的探讨胚胎多巴胺神经元移植对帕金森病大鼠的治疗作用。方法立体定向注射6-羟多巴胺建立帕金森病大鼠模型,随机分为对照组(n=12)和细胞移植组(n=12)。细胞移植组将荧光染料CM-DiI标记的大鼠胚胎多巴胺神经元立体定向注入帕金森病大鼠纹状体区,对照组于相同部位注入生理盐水。用阿扑吗啡诱导帕金森病大鼠旋转行为评估细胞移植的治疗作用。细胞移植8周后取大脑标本行冷冻切片,荧光显微镜下观察移植细胞在脑内存活情况。结果与对照组比较,移植多巴胺神经元能显著改善阿扑吗啡诱导帕金森病大鼠的异常旋转行为(P0.01)。移植8周后,仅少量多巴胺神经元存活。结论多巴胺神经元移植可短期内改善帕金森病大鼠的运动障碍,但长期疗效不佳,可能与移植多巴胺神经元长期存活率较低有关。     

Neuroprotective effects of human mesenchymal stem cells on dopaminergic neurons through anti-inflammatory action

Parkinson's disease (PD) is a common, progressive neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra (SN). Numerous studies have provided evidence suggesting that neuroinflammation plays an important role in the pathogenesis of PD. In this study, we used lipopolysaccharide (LPS)-induced in vitro and in vivo inflammation models to investigate whether human mesenchymal stem cells (hMSCs) have a protective effect on the dopaminergic system through anti-inflammatory mechanisms. The hMSC treatment significantly decreased LPS-induced microglial activation, tumor necrosis factor (TNF)-alpha, inducible nitric oxide synthase (iNOS) mRNA expression, and production of NO and TNF-alpha compared with the LPS-only treatment group. In co-cultures of microglia and mesencephalic dopaminergic neurons, hMSC treatment significantly decreased the loss of tyrosine hydroxylase-immunopositive (TH-ip) cells. The hMSC treatment in rats showed that TH-ip neuronal loss induced by LPS stimulation in the SN was considerably decreased and was clearly accompanied by a decrease in activation of microglia, as well as TNF-alpha and iNOS mRNA expression and production of TNF-alpha. These data suggest that hMSCs have a neuroprotective effect on dopaminergic neurons through anti-inflammatory actions mediated by the modulation of microglial activation. Along with various trophic effects and trans-differentiational potency, the anti-inflammatory properties of MSCs could have major therapeutic implications in the treatment of PD.     

Acupuncture prevents 6-hydroxydopamine-induced neuronal death in the nigrostriatal dopaminergic system in the rat Parkinson's disease model

Parkinson's disease (PD) is a chronic neurodegenerative disorder, and it has been suggested that treatments promoting survival and functional recovery of affected dopaminergic neurons could have a significant and long-term therapeutic value. In the present study, we investigated the neuroprotective effects of acupuncture on the nigrostriatal system in rat unilaterally lesioned with 6-hydroxydopamine (6-OHDA, 4 microg/microl, intrastriatal injection) using tyrosine hydroxylase (TH) and receptor for brain-derived neurotrophic factor, trkB, immunohistochemistries. Two weeks after the lesions were made, rats presented with asymmetry in rotational behavior (118.3 +/- 17.5 turns/h) following injection with apomorphine, a dopamine receptor agonist (0.5 mg/kg, sc). In contrast, acupunctural treatment at acupoints GB34 and LI3 was shown to significantly reduce this motor deficit (14.6 +/- 13.4 turns/h). Analysis via TH immunohistochemistry revealed a substantial loss of cell bodies in the substantia nigra (SN) (45.7% loss) and their terminals in the dorsolateral striatum ipsilateral to the 6-OHDA-induced lesion. However, acupunctural treatment resulted in the enhanced survival of dopaminergic neurons in the SN (21.4% loss) and their terminals in the dorsolateral striatum. Acupuncture also increased the expression of trkB significantly (35.6% increase) in the ipsilateral SN. In conclusion, we observed that only acupuncturing without the use of any drug has the neuroprotective effects against neuronal death in the rat PD model and these protective properties of acupuncture could be mediated by trkB.     

神经节苷脂对帕金森病鼠旋转行为、纹状体多巴胺浓度及黑质病理的影响

目的观察神经节苷脂对帕金森病（Ｐａｒｋｉｎｓｏｎｄｉｓｅａｓｅ，ＰＤ）鼠模型的旋转行为、纹状体多巴胺浓度及黑质病理的影响。方法将６－羟基多巴胺用立体定向法注入大鼠一侧中脑被盖腹侧区制作ＰＤ大鼠模型，并于同侧侧脑室注射混合型神经节苷脂（ａｍｉｘｅｄｇａｎｇｌｉｏｓｉｄｅｐｒｅｐａｒａｔｉｏｎ，ＧＭ），观察ＧＭ对由阿朴吗啡所诱发的旋转行为、受损侧纹状体多巴胺浓度及黑质病理的影响。结果ＧＭ能减轻ＰＤ大鼠模型的旋转行为、使受损侧纹状体多巴胺浓度下降和黑质神经细胞减少。结论ＧＭ可减轻６－羟基多巴胺对黑质多巴胺能神经元的损伤。     

神经细胞黏附分子在GDNF保护大鼠多巴胺能神经元中的作用

目的研究神经细胞黏附分子(neural cell adhesion molecule,NCAM)在胶质细胞系源性神经营养因子(glial cell line-derived neurotrophic factor,GDNF)保护帕金森(Parkinson's disease,PD)模型大鼠受损多巴胺(dopamine,DA)能神经元中的作用。方法右侧纹状体内立体定位注射6-羟多巴胺(6-OHDA)制备早期PD模型,而后分为4组:对照组(同侧黑质内注射PBS)、NCAM组(同侧黑质内仅注射anti-NCAM抗体)、GDNF组(同侧黑质内注射GDNF)、NCAM阻断组(同侧黑质内注射anti-NCAM抗体30min后注射GDNF),采用免疫组织化学染色技术和免疫印迹技术,观察各组酪氨酸羟化酶(tyrosine hydroxylase,TH)的表达变化。结果GDNF组黑质致密部TH阳性神经元数目及表达的量明显多于PBS组,差别有统计学意义;NCAM阻断组与GDNF组相比,该处TH阳性神经元数目及表达的量明显减少,差别有统计学意义。结论NCAM参与了GDNF保护DA能神经元的作用。     

尼莫地平对帕金森病模型小鼠黑质iNOS和COX-2表达的抑制作用

目的研究尼莫地平对1-甲基-4-苯基-1、2、3、6四氢吡啶(MPTP)所诱导的帕金森病(PD)模型小鼠黑质多巴胺能神经元的保护作用。方法雄性健康C57BL/6N小鼠随机分为对照组,腹腔注射生理盐水;模型组,腹腔注射MPTP(25 mg/kg);尼莫地平治疗组,每次注射MPTP前3 h灌胃给予尼莫地平(15 mg/kg)。观察各组小鼠行为学变化,免疫组织化学和免疫蛋白印迹法观察中脑黑质酪氨酸羟化酶(TH)、诱导型一氧化氮合酶(induciblenitricoxidesynthase,i NOS)和环氧化酶-2(Cyclooxygenase,COX-2)的表达变化。结果与对照组小鼠比较,MPTP模型组小鼠出现典型的PD症状,中脑黑质TH阳性神经元大量丢失,i NOS和COX-2阳性细胞显著增多,蛋白水平明显升高;经尼莫地平处理后,上述情况得到明显改善。结论在此PD小鼠模型中,尼莫地平通过抑制炎症因子i NOS和COX-2的表达,可对多巴胺能神经元起到一定的保护作用。     

Transfer of the von Hippel-Lindau gene to neuronal progenitor cells in treatment for Parkinson's disease

Neuronal progenitor cells (NPCs) may provide dopaminergic neurons for the treatment of Parkinson's disease (PD). However, transplantation of NPCs into the striatum by current methods has had limited success. It is possible to reverse the symptoms of PD in model rats but difficult to reverse them in humans because the number of dopaminergic neurons generated from NPCs is low. We transduced the von Hippel-Lindau (VHL) gene into NPCs isolated from embryonic rat brain. The NPCs with the transduced VHL gene efficiently differentiated into tyrosine hydroxylase-positive neurons in vitro. NPCs with the transduced VHL gene, which were labeled in advance with bromodeoxyuridine, were transplanted into the striatum of a rat model of PD. Numerous bromodeoxyuridine-tyrosine hydroxylase double-labeled cells were seen close to the transplant site, showing that the transplanted cells efficiently generated new dopaminergic neurons within the host striatum. Moreover, all of the animals with NPCs with VHL showed a remarkable decrease in apomorphine-induced rotations. These findings show that NPCs with the VHL gene can efficiently generate dopaminergic neurons and that a sufficient number of dopaminergic neurons can develop from them to reverse the symptoms of PD in humans. VHL gene transduction provides a new therapeutic approach for treatment of PD.     

Lactacystin诱导的帕金森病大鼠模型病理退行性改变的研究

目的 观察Lactacystin诱导的帕金森病(PD)模型大鼠的病理退行性改变,探索其发病机制.方法 取成年健康SD大鼠32只,采用随机数字表法分为实验组(16只)和对照组(16只),实验组左侧黑质致密部(SNc)注射蛋白酶体抑制剂Lactacystin,对照组以等体积生理盐水代替.分别存注射后1、3、5、7、9、11、14和21 d,观察两组大鼠的行为学变化;应用HE染色观察小胶质细胞并计数,免疫组化检测黑质及纹状体组织罗暗算酪氨酸羟化酶(TH)神经元变化和RT-PCR检测黑质部TH和α-synuclein mRNA的表达.结果 与对照组相比,实验组大鼠逐渐出现行为学改变:HE染色显示小胶质细胞在注射Lactacystin后第1天为(3501.92±57.32)个,第7天为(4895.50±52.67)个,第21天为(5340.18±52.87)个,与对照组(3271.23±63.76)个相比增高,差异具有统计学意义(P＜0.05):免疫组化检测显示黑质中多巴胺(DA)神经元在注射Lactacystin后逐渐变性死亡,第7天神经元数为(568.57±36.39)个,第21天为(119.67±21.06)个,与对照组(679.76±30.24)个相比,差异具有统计学意义(P＜0.05);免疫组化检测纹状体TH免疫阳性纤维显示其在注射Lactacystin后逐渐稀疏,强度逐渐变弱,实验组TH免疫阳性纤维平均光密度第7天为(0.1953±0.0076),与对照组(0.2412±0.0067)相比,差异无统计学意义(P＞0.05),第21天为(0.0781±0.0013)个,与对照组(0.2412±0.0067)个相比降低,差异具有统计学意义(P＜0.05).同时,实验组mRNA检测显示,THmRNA表达越来越少,而α-synuclein mRNA在残存TH神经元中逐渐增多.结论 Lactacystin诱导的PD模型大鼠的病理呈退行性改变.符合PD发病的隐匿性、缓慢进展性特征.     

Comparison of the capability of GDNF, BDNF, or both, to protect nigrostriatal neurons in a rat model of Parkinson's disease

Both glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) can protect nigrostriatal dopaminergic neurons from neurotoxins in rodent and monkey models of Parkinson's disease (PD). These two neurotrophic factors are usually tested individually. This study was designed to compare GDNF, BDNF, or both, for their capabilities to correct behavioral deficits and protect nigrostriatal dopaminergic neurons in a rat model of PD. Gene transfer used a helper virus-free Herpes Simplex Virus (HSV-1) vector system and a modified neurofilament heavy gene promoter that supports long-term expression in forebrain neurons. Rats received unilateral intrastriatal injections of HSV-1 vectors that express either GDNF or BDNF, or both vectors, followed by intrastriatal injections of 6-hydroxydopamine (6-OHDA). Recombinant GDNF or BDNF was detected in striatal neurons in rats sacrificed at 7 months after gene transfer. Of note, GDNF was significantly more effective than BDNF for both correcting behavioral deficits and protecting nigrostriatal dopaminergic neurons. Expression of both neurotrophic factors was no more effective than expression of only GDNF. These results suggest that GDNF is more effective than BDNF for correcting the rat model of PD, and that there are no detectable benefits from expressing both of these neurotrophic factors.     

The effects of L-3,4-dihydroxyphenylalanine and dopamine agonists on dopamine neurons in the progressive hemiparkinsonian rat models

OBJECTIVES: Dopamine replacement with the precursor L-3,4-dihydroxyphenylalanine (L-DOPA) and dopamine receptor agonists is the standard therapy for the symptomatic treatment of Parkinson's disease (PD). Whether L-DOPA and dopamine agonists may either accelerate or slow the degeneration of dopamine neurons is still controversial with conflicting data from both in vitro and in vivo experiments. We aimed to verify the influence of L-DOPA and receptor-selective dopamine agonists on dopamine neurons in the progressive hemiparkinsonian rat models. METHODS: We administered different doses of L-DOPA, D1 selective agonist SKF38393, D2 selective agonist quinpirole and D2/D3 agonist pramipexole intraperitoneally for 9 weeks to the rats with progressive nigrostriatal lesions produced by injecting 6-hydroxydopamine (6-OHDA) into the striatum. After 3, 6 and 9 weeks of administration of dopaminergic agents, we performed the behavioral test using the forepaw adjusting step (FAS) test and anatomical analysis using tyrosine hydroxylase (TH) immunohistochemical staining and TH western blots. RESULTS: Only in the high dose (100 mg/kg/d) L-DOPA treated rats, TH immunoreactive (TH-IR) cells were significantly decreased compared with other groups (p<0.01). We could not detect any influence of dopamine agonists on the behavior or the degeneration of dopaminergic neurons, regardless of their receptor selectivity. DISCUSSION: In conclusion, we demonstrated the potential toxicity of high dose of L-DOPA, but did not observe any protective effect of dopamine agonists in the progressive hemiparkinsonian rat models.     

Postnatal development of the dopaminergic neurons in the rat mesencephalon

The two mesencephalic dopaminergic systems in the developing rat brain were investigated immunohistochemically by dopamine and tyrosine hydroxylase and the results were quantitatively analyzed with a computer. The number of the dopaminergic neurons in the substantia nigra and the ventral tegmentum area did not change significantly during the postnatal development. Dopaminergic terminals in the lateral septum peaked at postnatal days (PD) 30, when the cell size in middle third of the ventral tegmentum area which was suggested as an origin of this projection system, increased largely. Patchy structures in the striatum were shown most distinctly at PD 7 and disappeared at PD 35 using dopamine antibody, but there were no changes in the cell size of the substantia nigra from PD 14 to 75. Dopaminergic neurons, in general, do not show a transient change in ontogeny.