• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.140-147
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• 2002

시상은 체감각 정보를 처리하는데 있어서 매우 중요한 역할을 하는 부위이다. 본 연구는 운동장애 환자의 시상에서 뉴론의 활동 특성을 알아보기 위해 수행되었다. 그 결과 체감각으로서의 운동자극에 반응하는 뉴론이 essential tremor (ET) 환자의 nucleus ventralis intermedius (VIM)에서 발견되었다. ET 환자 뉴론의 평균 활동율(firing rate)은 Parkinson's disease (PD) 환자 보다 높았다. 또한 ET 환자의 VIM에서 운동자극에 반응하는 뉴론의 평균 활동율은 PD 환자 보다 높았다. 하지만 촉각자극(touch)에 반응하는 nucleus ventralis caudalis (VC) 뉴론의 활동율은 ET와 PD 집단간에 차가 없었다. Bursting activity를 나타내는 뉴론은 nucleus ventralis oralis anterior (VOP)에서 ET집단이 PD 집단보다 적었다. tremor cell은 VIM에서 PD 보다 ET집단이 더 적었다. 이러한 결과는 체감각 자극에 반응하는 시상 뉴론의 특성이 운동장애의 유형에 따라 서로 다르다는 것을 시사한다.

• Biomolecules & Therapeutics
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• v.31 no.4
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• pp.402-410
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• 2023

Long-term administration of levodopa (L-DOPA) to patients with Parkinson's disease (PD) commonly results in involuntary dyskinetic movements, as is known for L-DOPA-induced dyskinesia (LID). 5-Hydroxytryptophan (5-HTP) has recently been shown to alleviate LID; however, no biochemical alterations to aberrant excitatory conditions have been revealed yet. In the present study, we aimed to confirm its anti-dyskinetic effect and to discover the unknown molecular mechanisms of action of 5-HTP in LID. We made an LID-induced mouse model through chronic L-DOPA treatment to 6-hydroxydopamine-induced hemi-parkinsonian mice and then administered 5-HTP 60 mg/kg for 15 days orally to LID-induced mice. In addition, we performed behavioral tests and analyzed the histological alterations in the lesioned part of the striatum (ST). Our results showed that 5-HTP significantly suppressed all types of dyskinetic movements (axial, limb, orolingual and locomotive) and its effects were similar to those of amantadine, the only approved drug by Food and Drug Administration. Moreover, 5-HTP did not affect the efficacy of L-DOPA on PD motor manifestations. From a molecular perspective, 5-HTP treatment significantly decreased phosphorylated CREB and ΔFosB expression, commonly known as downstream factors, increased in LID conditions. Furthermore, we found that the effects of 5-HTP were not mediated by dopamine1 receptor (D1)/DARPP32/ERK signaling, but regulated by AKT/mTOR/S6K signaling, which showed different mechanisms with amantadine in the denervated ST. Taken together, 5-HTP alleviates LID by regulating the hyperactivated striatal AKT/mTOR/S6K and CREB/ΔFosB signaling.

• Molecules and Cells
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• v.44 no.7
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• pp.493-499
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• 2021

Parkinson's disease (PD) is characterized by a progressive loss of dopamine-producing neurons in the midbrain, which results in decreased dopamine levels accompanied by movement symptoms. Oral administration of l-3,4-dihydroxyphenylalanine (L-dopa), the precursor of dopamine, provides initial symptomatic relief, but abnormal involuntary movements develop later. A deeper understanding of the regulatory mechanisms underlying dopamine homeostasis is thus critically needed for the development of a successful treatment. Here, we show that p21-activated kinase 4 (PAK4) controls dopamine levels. Constitutively active PAK4 (caPAK4) stimulated transcription of tyrosine hydroxylase (TH) via the cAMP response element-binding protein (CREB) transcription factor. Moreover, caPAK4 increased the catalytic activity of TH through its phosphorylation of S⁴⁰, which is essential for TH activation. Consistent with this result, in human midbrain tissues, we observed a strong correlation between phosphorylated PAK4^S474, which represents PAK4 activity, and phosphorylated TH^S40, which reflects their enzymatic activity. Our findings suggest that targeting the PAK4 signaling pathways to restore dopamine levels may provide a new therapeutic approach in PD.

• Journal of Korean Neurosurgical Society
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• v.44 no.1
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• pp.26-35
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• 2008

Objective : In the evaluation of patients with Parkinson's disease (PD), most neurologists only see their patients during a limited period of their fluctuating 24-hour-a-day lives. This study aimed to assess the short-term outcome of STN stimulation for patients with advanced PD evaluated in a 24-hour monitoring unit for movement disorder (MUMD) using a prospective protocol. Methods : Forty-two patients with advanced PD consecutively treated with bilateral STN stimulation using multi-channel microelectrode recording were included in this study. All patients were evaluated using a 24-hour MUMD with a video recording/editing system and were evaluated with a prospective protocol of the Unified Parkinson's Disease Rating Scale, Hoehn and Yahr Staging, Schwab and England Activities of Daily Living, levodopa equivalent daily dose (LEDD), Short Form-36 Health Survey, and neuropsychological tests. Magnetic resonance (MR) images of the brain were performed prior to and six months after surgery. Results : All patients were evaluated at three and six months after surgery. There was a rapid and significant improvement of the motor symptoms, especially in tremor and rigidity, after STN stimulation with low morbidity. Dyskinesia was markedly decreased with much lowered LEDD values by 50% after STN stimulation. 1.5T MR images were safely taken according to the manufacturer's guidelines at six months after surgery without any adverse effects in 41 patients treated with STN stimulations. Conclusion : Evaluations in a 24-hour monitoring unit could reduce the dose of medication efficiently to an optimal level with patients' comfort and improve the clinical symptoms in harmony with STN stimulation.

• Molecules and Cells
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• v.37 no.9
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• pp.672-684
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• 2014

The exact causes of cell death in Parkinson's disease (PD) remain unknown despite extensive studies on PD.The identification of signaling and metabolic pathways involved in PD might provide insight into the molecular mechanisms underlying PD. The neurotoxin 1-methyl-4-phenylpyridinium ($MPP^+$) induces cellular changes characteristic of PD, and $MPP^+$-based models have been extensively used for PD studies. In this study, pathways that were significantly perturbed in $MPP^+$-treated human neuroblastoma SH-EP cells were identified from genome-wide gene expression data for five time points (1.5, 3, 9, 12, and 24 h) after treatment. The mitogen-activated protein kinase (MAPK) signaling pathway and endoplasmic reticulum (ER) protein processing pathway showed significant perturbation at all time points. Perturbation of each of these pathways resulted in the common outcome of upregulation of DNA-damage-inducible transcript 3 (DDIT3). Genes involved in ER protein processing pathway included ubiquitin ligase complex genes and ER-associated degradation (ERAD)-related genes. Additionally, overexpression of DDIT3 might induce oxidative stress via glutathione depletion as a result of overexpression of CHAC1. This study suggests that upregulation of DDIT3 caused by perturbation of the MAPK signaling pathway and ER protein processing pathway might play a key role in $MPP^+$-induced neuronal cell death. Moreover, the toxicity signal of $MPP^+$ resulting from mitochondrial dysfunction through inhibition of complex I of the electron transport chain might feed back to the mitochondria via ER stress. This positive feedback could contribute to amplification of the death signal induced by $MPP^+$.

• Anatomy and Cell Biology
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• v.57 no.3
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• pp.431-445
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• 2024

Parkinson's disease (PD) affects about 8.5 million individuals worldwide. Oxidative and inflammatory cascades are implicated in the neurological sequels, that are mostly unresolved in PD treatments. However, proper nutrition offers one of the most effective and least costly ways to decrease the burden of many diseases and their associated risk factors. Moreover, prevention may be the best response to the progressive nature of PD, thus, the therapeutic novelty of honey and levodopa may be prospective. This study aimed to investigate the neuroprotective role of honey and levodopa against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced oxidative stress. Fifty-four adult male Swiss mice were divided into control and PD model groups of 27 mice. Each third of the control mice either received phosphate buffered saline, honey, or levodopa for 21 days. However, each third of the PD models was either pretreated with honey and levodopa or not pretreated. Behavioral studies and euthanasia were conducted 2 and 8 days after MPTP administration respectively. The result showed that there were significantly (P<0.05) higher motor activities in the PD models pretreated with the honey as well as levodopa. furthermore, the pretreatments protected the midbrain against the chromatolysis and astrogliosis induced by MPTP. The expression of antioxidant markers (glutathione [GSH] and nuclear factor erythroid 2-related factor 2 [Nrf2]) was also significantly upregulated in the pretreated PD models. It is thus concluded that honey and levodopa comparably protected the substantia nigra pars compacta neurons against oxidative stress by modulating the Nrf2 signaling molecule thereby increasing GSH level to prevent MPTP-induced oxidative stress.

• BMB Reports
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• v.48 no.7
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• pp.395-400
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• 2015

Parkinson's disease (PD) is a neurodegenerative disability caused by a decrease of dopaminergic neurons in the substantia nigra (SN). Although the etiology of PD is not clear, oxidative stress is believed to lead to PD. Catalase is antioxidant enzyme which plays an active role in cells as a reactive oxygen species (ROS) scavenger. Thus, we investigated whether PEP-1-Catalase protects against 1-methyl-4-phenylpyridinium (MPP⁺) induced SH-SY5Y neuronal cell death and in a 1-methyl-4-phenyl-1,2,3,6-trtrahydropyridine (MPTP) induced PD animal model. PEP-1-Catalase transduced into SH-SY5Y cells significantly protecting them against MPP⁺-induced death by decreasing ROS and regulating cellular survival signals including Akt, Bax, Bcl-2, and p38. Immunohistochemical analysis showed that transduced PEP-1-Catalase markedly protected against neuronal cell death in the SN in the PD animal model. Our results indicate that PEP-1-Catalase may have potential as a therapeutic agent for PD and other oxidative stress related diseases. [BMB Reports 2015; 48(7): 395-400]

• Journal of the Korean Society of Radiology
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• v.8 no.4
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• pp.163-170
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• 2014

This study is to investigate neuro-anatomical correlation between neuropsychological results and cerebral cortex thickness of cognitive ability in the brain MRI targeting the patients with mild cognitive impairment. It was that 78 people who were diagnosed as first Parkinson's disease followed by neuropsychological screening battery(Parkinson's disease with mild cognitive impairment: 39 people; Parkinson's disease with normal cognition: 39 people) and 32 people of normal group were selected. Correlation between mild cognitive impairment and normal cognitive impairment and correlation between neuropsychological screening battery and cerebral cortex thickness in the brain MRI were performed by independent sample t-test or Pearson correlation coefficient and then level of significance of collected data was verified in p<0.05. As a result, cerebral cortex thickness of the Parkinson's disease with mild cognitive impairment in both side precuneas and right inferiortemporal lobe had statistically significant decrease. In addition, function of visuospatial ability, verbal and visual memory was reduced in neuropsychological screening battery for cognitive assessment. Especially, there was correlation between neuropsychological screening battery of verbal and visual memory anatomical left precuneus.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.5
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• pp.565-572
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• 1998

The present study was to evaluate the protective effects of bromocriptine, which is known as $D_2$ dopamine receptor agonist and used for the treatment of patients with Parkinson's disease (PD), on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in vitro and in vivo. Lipid peroxidation product (malondialdehyde; MDA) produced by the administration of 6-OHDA was profoundly reduced following the treatment of bromocriptine in a dose-dependent manner in rabbit brain homogenate. Quinone formation by 6-OHDA autoxidation was also attenuated, and its effect was as potent as other antioxidants. Pretreatment of bromocriptine reduced the cytotoxicity of 6-OHDA on SH-SY5Y neuroblastoma cell lines dose-dependently. The loss of striatal dopamine and its metabolite, DOPAC (dihydroxyphenylacetic acid) as well as increase of MDA production caused by intrastriatal injection of 6-OHDA was significantly recovered following the treatment of bromocriptine. The present study clearly showed that bromocriptine had a protective action against 6-OHDA-induced neurotoxicity. These results suggest that bromocriptine has the antioxidant properties, which could be another advantage for delaying the progress of Parkinson's disease.

• Korean Journal of Acupuncture
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• v.39 no.2
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• pp.34-42
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• 2022

Objectives : Parkinson's disease (PD) is a neurodegenerative disease caused by dopaminergic neuronal death in the substantia nigra pars compacta. PD is known to be linked with mitochondrial dysfunction and increased oxidative stress. In this study, anti-cytotoxic and anti-oxidative effect of 12 herbal formulae were compared. Methods : According to experts' advice, 12 types of herbal formulae (Gamisoyosan, Galgeuntang, Galgeunhaegitang, Banhabaekchoolcheonmatang, Bojungikgitang, Boheotang, Sihogyejitang, Sihosogantang, Sihocheonggantang, Ojeoksan, Cheongsanggyeontongtang and Palmultang) were selected from 56 types of herbal formulae covered by the National Health Insurance Service in Korea. To detect anti-oxidative effect, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was performed, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to detect anti-cytotoxic effect of 12 herbal formulae using SH-SY5Y human neuroblastoma cells. Results : In DPPH assay, anti-oxidant activity was increased in a dose-dependent manner and half maximal inhibitory concentration was highest in the order of Galgeuntang, Gamisoyosan, Galgeunhaegitang, Ojeoksan, Palmultang, Sihogyejitang, Sihosogantang, Cheongsanggyeontongtang, Sihocheonggantang, Bojungikgitang, Boheotang and Banhabaekchoolcheonmatang. In MTT assay, concentration of 80% cell survival was highest in the order of Sihosogantang, Cheongsanggyeontongtang, Sihocheonggantang, Sihogyejitang, Bojungikgitang, Galgeuntang, Ojeoksan, Boheotang, Palmultang, Galgeunhaegitang, Banhabaekchoolcheonmatang and Gamisoyosan. Formulae with more than 50% DPPH radical scavenging activity at concentrations for 80% cell survival were Sihosogantang, Cheongsanggyeontongtang, Sihogyejitang, Galgeuntang and Sihocheonggantang. Conclusions : Sihosogantang, Cheongsanggyeontongtang, Sihogyejitang, Galgeuntang and Sihocheonggantang extracts can be candidate medicines for PD, but the effect should be validated in PD models.