• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.743-746
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• 2003

The major pathological lesion in Parkinson's disease(PD) is selective degeneration and loss of pigmented dopaminergic neurons in substantia nigra (SN). Although the initial cause and subsequent molecular signaling mechanisms leading to the dopaminergic cell death underlying the PD process is elusive, the potent neurotrophic factors (NTFs), brain derived neurotrophic factor (BDNF) and glial cell line derived neurotrophic factor (GDNF), are known to exert dopaminergic neuroprotection both in vivo and in vitro models of PD employing the neurotoxin, MPTP. BDNF and its receptor, trkB are expressed in SN dopaminergic neurons and their innervation target. Thus, neurotrophins may have autocrine, paracrine and retrograde transport effects on the SN dopaminergic neurons. This study determined the BDNF secretion from SN dopaminergic neurons by ELISA. Regulation of BDNF synthesis/release and changes in signaling pathways are monitored in the presence of free radical donor, NO donor and mitochondrial inhibitors. Also, this study shows that BDNF is able to promote survival and phenotypic differentiation of SN dopaminergic neurons in culture and protect them against MPTP-induced neurotoxicity via MAP kinase pathway.

• 대한의생명과학회지
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• 제15권2호
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• pp.127-133
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• 2009

This study was designed to investigate the effects of high concentration of (-)-epigallocatechin-3-gallate(EGCG) on the neuronal activity of rat substantia nigra dopaminergic neurons. Sprague-Dawley rats aged 14 to 16 days were decapitated under ether anesthesia. After treatment with pronase and thermolysin, the dissociated dopaminergic neurons were transferred into a chamber on an inverted microscope. Spontaneous action potentials and potassium currents were recorded by standard patch-clamp techniques under current and voltage-clamp modes respectively. 18 dopaminergic neurons(80%) revealed inhibitory responses to 40 and 100 ${\mu}M$ of EGCG and 4 neurons(20%) did not respond to EGCG. The spike frequency and resting membrane potential of these cells were decreased by EGCG. The amplitude of afterhyperpolarization was increased by EGCG. Whole potassium currents of dopaminergic neurons were increased by EGCG(n=10). These experimental results suggest that high concentration EGCG decreases the neuronal activity of the dopaminergic neurons by altering the resting membrane potential and afterhyperpolarization.

• Korean Journal of Acupuncture
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• 제38권3호
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• pp.133-139
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• 2021

Objectives : Parkinson's disease is a neurodegenerative disease caused by a decrease in the dopaminergic neurons in the substantia nigra. The abnormal expression of solute carrier family 6 member 4 (Slc6a4) has been reported in patients with Parkinson's disease. Methods : In this study, we used MPTP to examine the changes in the expression of Slc6a4 in the brain of mice with Parkinson's disease and investigate its effect on dopaminergic neuronal cell death. Results : In the examination of the Slc6a4 expression in the substantia nigra of MPTP-treated mice for 4 weeks. The gene expression was increased compared to the normal group. To investigate the relationship between Slc6a4 and dopaminergic neurons, we performed a study using siRNA of Slc6a4 in the dopaminergic neuronal cell line SH-SY5Y. Using the siRNA of Slc6a4 to evaluate gene expression, it revealed that the tyrosine hydroxylase (TH) expression increases when Slc6a4 decreases. Moreover, this confirms its effects on the dopaminergic neurons. Additionally, through the evaluation of factors related to apoptosis, in particular, it was established that the value of bax/bcl2 decreased and was affected. These results suggest that a decreased Slc6a4 expression induces an increase in TH expression, providing a mechanism of action for dopaminergic neurons regulated by Slc6a4 expression. Conclusions : Slc6a4 is deemed to be involved in the regulation of dopaminergic neurons, suggesting that an increased Slc6a4 expression induced by MPTP may influence a reduction of dopaminergic neurons.

• 한국안광학회지
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• 제5권2호
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• pp.15-20
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• 2000

성체 소의 망막에 존재하는 doparminergic 신경세포의 형태를 연구하였다. Dopaminerglc 세포는 항체면역세포화학적 방법을 이용하여 확인하였다. Tyrosine hydroxylase 면역 반응 신경 세포의 대부분은 내핵층의 가장 깊은 부분에 위치했다. 이들 세포들의 돌기들은 단층이었으며 그리고 내망상층의 1층내에 위치했다. Tyrosine-hydroxylase 면역 반응되는 두 번째 주요 세포 집단은 치환된 amacrine 세포들이다. 치환된 tyrosine-hydroxylase 면역 반응 amacrine 세포의 돌기들도 역시 내망상층의 1층내에 나타났다. 소수의 신경 세포의 돌기들은 외망상층에서 나타났다. 매우 낮은 밀도의 신경세포들은 내망상층의 중간과 깊은 층에서 tyrosine-hydroxylase 면역 반응 돌기들의 추가적인 층을 가졌다. Doparminergic 신경세포의 돌기들은 방사선형으로 넓게 신장되어 큰 모양을 형성하였고 수상돌기의 가지들은 적당하게 뻗어 있었다. 이러한 돌기들은 때때로 varicosity를 가지지만 "dendritic rings"을 형성하지는 않았다. 본연구의 결과는 doparminergic 세포는 소의 망막내 특이 신경세포 형태를 구성하는 것을 알 수 있었다.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.267.2-267.2
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• 2002

MPP$\^$＋/ is known to be a neurotoxic substance that induces the degeneration of dopaminergic neurons and a Parkinsonism-like syndrome. MPP$\^$＋/ is retained intracellularly or accumulated in dopaminergic neurons via the dopamine-reuptake system. It inhibits mitochondrial electron transport in dopaminergic neurons. In addition. it generates hydroxyl radicals. which cause the peroxidation of membrane lipid or damage DNA. (omitted)

• Journal of Biomedical and Translational Research
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• 제19권4호
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• pp.125-129
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• 2018

Dopaminergic neurons are one of the major neuronal components in the brain. Mesencephalon dopamine (DA) neurogenesis takes place in the ventricular zone of the floor plate, when DA progenitors divide to generate postmitotic cells. These cells migrate through the intermediate zone while they differentiate and become DA neurons on reaching the mantle zone. However, neurogenesis and neuronal migration on dopaminergic neurons remain largely unexplored in the mesencephalon development. This study presents neurogenesis and neuronal migration patterns of dopaminergic neurons during mesencephalic development of the mouse. Neurons from embryonic day (E) 10-14 were labelled by a single injection of 5-bromodeoxyuridine and immunohistochemistry was performed. The neurogenesis occurred mainly at the E10 and E11, which was uniformly distributed in the mesencephalic region, but neurons after E13 were observed only in the dorsal mesencephalon. At the postnatal day 0 (P0), E10 generated neurons were spread out uniformly in the whole mesencephalon whereas E11-originated neurons were clearly depleted in the red nucleus region. DA neurons mainly originated in the ventromedial mesencephalon at the early embryonic stage especially E10 to E11. DA neurons after E12 were only observed in the ventral mesencephalon. At E17, E10 labelled neurons were only observed in the substantia nigra (SN) region. Our study demonstrated that major neurogenesis occurred at E10 and E11. However, neuronal migration continued until neonatal period during mesencephalic development.

• The Korean Journal of Physiology and Pharmacology
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• 제26권5호
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• pp.307-312
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• 2022

It is well known that dopamine transmission from the ventral tegmental area (VTA) modulates motivated behavior and reinforcement learning. Although dopaminergic neurons are the major type of VTA neurons, recent studies show that a significant proportion of the VTA contains GABAergic and type 2 vesicular glutamate transporter (VGLUT2)-positive neurons. The non-dopaminergic neurons are also critically involved in regulating motivated behaviors. Some VTA neurons appear to co-release two different types of neurotransmitters. They are VGLUT2-DA neurons, VGLUT2-GABA neurons and GABA-DA neurons. These co-releasing neurons show distinct features compared to the neurons that release a single neurotransmitter. Here, we review how VTA cell populations wire to the other brain regions and how these projections differentially contribute to motivated behavior through the distinct molecular mechanism. We summarize the activities, projections and functions of VTA neurons concerning motivated behavior. This review article discriminates VTA cell populations related to the motivated behavior based on the neurotransmitters they release and extends the classical view of the dopamine-mediated reward system.

• 대한본초학회지
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• 제28권5호
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• pp.21-28
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• 2013

Objectives : The aim of this study was to investigate the neuroprotective effects and mechanisms of Cyperi Rhizoma extracts (CRE) using in vitro and in vivo models of Parkinson's disease (PD). Methods : We evaluated the neuroprotective effect of CRE against 1-methyl-4-phenylpyridinium (MPP+) toxicity using tyrosine hydroxylase immunohistochemistry (IHC) in primary rat mesencephalic dopaminergic neurons. In addition, the effect of CRE was evaluated in mice PD model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). For evaluations, C57bl/6 mice were orally treated with CRE 50 mg/kg for 5 days and were injected intraperitoneally with MPTP (20 mg/kg) at 2 h intervals on the last day. To identify the CRE affects on MPTP-induced neuronal loss of dopaminergic neurons in substantia nigra pars compacta (SNpc) and striatum of mice, the behavioral tests and IHC analysis were carried out. Also, we conducted nitric oxide (NO) and tumor necrosis factor-alpha (TNF-${\alpha}$) assay in dopaminergic neurons and IHC using glial markers in SNpc of mice to assess the anti-inflammation effects. Results : In primary mesencephalic culture system, CRE protected dopaminergic cells against $10{\mu}M$ MPP+-induced toxicity at 0.2 and $1.0{\mu}g/mL$. In the behavior tests, CRE treated group showed improved motor deteriorations than those in the MPTP only treated group. CRE significantly protected striatal dopaminergic damage from MPTP-induced neurotoxicity in mice. Moreover, CRE inhibited productions of NO and TNF-${\alpha}$ in dopaminergic culture system and activation of astrocyte and microglia in SNpc of the mice. Conclusion : We concluded that CRE shows anti-parkinsonian effect by protecting dopaminergic neurons against MPP+/MPTP toxicities through anti-inflammatory actions.

• Biomolecules & Therapeutics
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• 제27권5호
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• pp.442-449
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• 2019

This study sought to evaluate the effects of Asiatic acid in LPS-induced BV2 microglia cells and 1-methyl-4-phenyl-pyridine ($MPP^+$)-induced SH-SY5Y cells, to investigate the potential anti-inflammatory mechanisms of Asiatic acid in Parkinson's disease (PD). SH-SY5Y cells were induced using $MPP^+$ to establish as an in vitro model of PD, so that the effects of Asiatic acid on dopaminergic neurons could be examined. The NLRP3 inflammasome was activated in BV2 microglia cells to explore potential mechanisms for the neuroprotective effects of Asiatic acid. We showed that Asiatic acid reduced intracellular production of mitochondrial reactive oxygen species and altered the mitochondrial membrane potential to regulate mitochondrial dysfunction, and suppressed the NLRP3 inflammasome in microglia cells. We additionally found that treatment with Asiatic acid directly improved SH-SY5Y cell viability and mitochondrial dysfunction induced by $MPP^+$. These data demonstrate that Asiatic acid both inhibits the activation of the NLRP3 inflammasome by downregulating mitochondrial reactive oxygen species directly to protect dopaminergic neurons from, and improves mitochondrial dysfunction in SH-SY5Y cells, which were established as a model of Parkinson's disease. Our finding reveals that Asiatic acid protects dopaminergic neurons from neuroinflammation by suppressing NLRP3 inflammasome activation in microglia cells as well as protecting dopaminergic neurons directly. This suggests a promising clinical use of Asiatic acid for PD therapy.

• Journal of Acupuncture Research
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• 제32권1호
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• pp.23-36
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• 2015

Objectives : This study was designed to investigate the neuroprotective effects of Hominis-Placenta (HP)on dopaminergic neurons. Methods : We examined the effect of invitro administration of HP against 1-methyl-4-phenylpyridinium( MPP+)-induced dopaminergic cell loss in primary mesencephalic culture and also used behavioral tests and performed analysis in the striatum and the substantia nigra of mouse brain, to confirm the effect of HP on dopaminergic neurons in an invivo 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced PD mouse model. Animals were assigned to four groups: (1) Group 1(vehicle-treatedgroup), (2) Group 2(MPTPonlytreated group), (3) Group 3(MPTP+ saline-treated/$ST_{36}$ group), and (4) Group 4(MPTP+HP-treated/$ST_{36}$ group). HP at $20{\mu}L$ of 48 mg/kg dose was injected at $ST_{36}$ for 4 weeks at 2-day intervals. MPTP in saline was injected intraperitoneally each day for 5 days from the $8_{th}$ treatment of HP. We performed the pole test and rota-rod test on the first and seventh day after the last MPTP injection. To investigate the effect of HP on dopaminergic neurons, we performed analysis in the striatum and the substantia nigra of mouse brain after treatment with HP and/or MPTP. Results : Treatment with HP had no influence on cell proliferation and caused no cell toxicity in $PC_{12}$ and $HT_{22}$ cells. Our study showed that HP significantly prevented cell loss and protected neurites against MPP+ toxicity. Although the invivo treatment of HP herbal acupuncture at $ST_{36}$ showed a tendency to improve movement ability and protected dopaminergic cells and fibers in the substantia nigra and the striatum, it did not show significant changes compared with the MPTP treated group. Conclusions : These data suggest that HP could be a potential treatment strategy in neurodegenerative diseases such as Parkinson's disease.