• The Korean Journal of Physiology and Pharmacology
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• 제22권5호
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• pp.585-595
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• 2018

Amitriptyline, a tricyclic antidepressant, is commonly used to treat depression and neuropathic pain, but its mechanism is still unclear. We tested the effect of amitriptyline on 5-hydroxytryptamine 3 ($5-HT_3$) receptor currents and studied its blocking mechanism because the clinical applications of amitriptyline overlapped with $5-HT_3$ receptor therapeutic potentials. Using a whole-cell voltage clamp method, we recorded the currents of the $5-HT_3$ receptor when 5-HT was applied alone or co-applied with amitriptyline in cultured NCB-20 neuroblastoma cells known to express $5-HT_3$ receptors. To elucidate the mechanism of amitriptyline, we simulated the $5-HT_3$ receptor currents using Berkeley $Madonna^{(R)}$ software and calculated the rate constants of the agonist binding and receptor transition steps. The $5-HT_3$ receptor currents were inhibited by amitriptyline in a concentration-dependent, voltage-independent manner, and a competitive mode. Amitriptyline accelerated the desensitization of the $5-HT_3$ receptor. When amitriptyline was applied before 5-HT treatment, the currents rose slowly until the end of 5-HT treatment. When amitriptyline was co-applied with 5-HT, currents rose and decayed rapidly. Peak current amplitudes were decreased in both applications. All macroscopic currents recorded in whole cell voltage clamping experiments were reproduced by simulation and the changes of rate constants by amitriptyline were correlated with macroscopic current recording data. These results suggest that amitriptyline blocks the $5-HT_3$ receptor by close and open state blocking mechanisms, in a competitive manner. We could expand an understanding of pharmacological mechanisms of amitriptyline related to the modulation of a $5-HT_3$ receptor, a potential target of neurologic and psychiatric diseases through this study.

• Natural Product Sciences
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• 제13권3호
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• pp.268-271
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• 2007

Glutamate-induced oxidative injury contributes to neuronal degeneration in many central nervous system (CNS) diseases, such as epilepsy and ischemia. Bioassay-guided fractionation of the MeOH extract of the seeds of Alpinia katsumadai Hayata (Zingiberaceae) furnished three phenolic compounds, alpinetin (1), pinocembrin (2), and (+)-catechin (3). Compounds 2 and 3 showed the potent neuroprotective effects on glutamate-induced neurotoxicity and reactive oxygen species (ROS) generation in the mouse hippocampal HT22 cells. In addition, Compounds 2 and 3 showed significant DPPH free radical scavenging effect. These results suggest that compounds 2 and 3 could be the effective candidates for the treatment of ROS-related neurological diseases.

• Journal of Ginseng Research
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• 제42권2호
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• pp.225-228
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• 2018

Our results suggested that thermal stress can lead to activation of hippocampal cell damage and reduction of memory-associated molecules in HT22 cells. These findings also provide a part of molecular rationale for the role of ginsenoside Rg5 as a potent cognitive impairment preventive compound in blocking the initiation of hippocampal damage.

• Natural Product Sciences
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• 제12권3호
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• pp.134-137
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• 2006

Four lignan compounds including gomisin J (1), schizandrin (2), gomisin A (3), and angeloyl gomisin H (4) have been isolated from the MeOH extract of Schizandra chinensis fruits. The evaluation for protective effect of compounds 1-4 against tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity in hippocampal HT22 cell line was conducted. Compound 1 showed significant protective effect with an $EC_{50}$ value of $43.3{\pm}2.3\;{\mu}M$, whereas compounds 2-4 were inactive. Trolox, one of the well-known antioxidant, used as a positive control, and also showed protective effect with an $EC_{50}$ value of $213.8{\pm}8.4\;{\mu}M$. These results suggest that compound 1 may possess the neuroprotective activity against oxidant-induced cellular injuries.

• Natural Product Sciences
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• 제13권2호
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• pp.101-104
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• 2007

Four isoflavones including tectorigenin (1), irisflorentin (2), irigenin (3), and tectoridin (4) have been isolated from the 70% EtOH extract of Belamcanda chinensis rhizome. The evaluation for protective effect of compounds 1-4 against glutamate-induced cytotoxicity in hippocampal HT22 cell line was conducted. Compound 1 showed significant protective effect with an EC$_{50}$ value of 67.25 ${\pm}$ 1.2 ${\mu}$M, whereas compounds 2-4 were inactive. These results suggest that compound 1 may possess the neuroprotective activity against oxidative cellular injures.

• 생약학회지
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• 제50권2호
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• pp.118-123
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• 2019

Glutamate acts as an important neurotransmitter in brain. However, high concentration of glutamate showed an excitatory neurotoxicity and resulted to neuronal cell death. Neuronal cell death is known for one of the reason of Alzheimer's disease, a neurodegenerative disease. We tried to find neuroprotective medicinal plants by neuroprotection activity against glutamate injured HT22 cells as a model system. In the course of bioscreening of various medicinal plants, Taraxacum platycarpum extract showed significant neuroprotective activity. We tried to elucidate mechanisms of neuroprotective activity. T. platycarpum extract reduced ROS and intracellular $Ca^{2+}$ concentration increased by glutamate induced neurotoxicity. In addition, mitochondrial membrane potential was restored to the control level. Also, glutathione level, glutathione reductase and glutathione peroxidase activity were increased by T. platycarpum extract treatment. These data suggested that T. platycarpum showed neuroprotective activity via antioxidative activity.

• Biomolecules & Therapeutics
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• 제27권2호
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• pp.145-151
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• 2019

Methamphetamine (METH) acts strongly on the nervous system and damages neurons and is known to cause neurodegenerative diseases such as Alzheimer's and Parkinson's. Flavonoids, polyphenolic compounds present in green tea, red wine and several fruits exhibit antioxidant properties that protect neurons from oxidative damage and promote neuronal survival. Especially, epicatechin (EC) is a powerful flavonoid with antibacterial, antiviral, antitumor and antimutagenic effects as well as antioxidant effects. We therefore investigated whether EC could prevent METH-induced neurotoxicity using HT22 hippocampal neuronal cells. EC reduced METH-induced cell death of HT22 cells. In addition, we observed that EC abrogated the activation of ERK, p38 and inhibited the expression of CHOP and DR4. EC also reduced METH-induced ROS accumulation and MMP. These results suggest that EC may protect HT22 hippocampal neurons against METH-induced cell death by reducing ER stress and mitochondrial damage.

• 생약학회지
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• 제52권1호
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• pp.19-25
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• 2021

We previously reported that lonicerin isolated from Lonicera japonica methanolic extract had potent neuro-protective activities in neuronal cell death injured by excessive glutamate. In this study, we tried to confirm the neuroprotective activities of L. japonica extract and lonicerin in glutamate injured HT22 cells and establish mechanisms of neuroprotective action of lonicerin. We used HT22 cell death injured by glutamate as a bioassay system. The compound decreased reactive oxygen species increased by excessive glutamate treatment in HT22 cells. Also, Ca2+ concentration was decreased by lonicerin treatment. This compound made mitochondrial membrane potential maintain to normal condition. Lonicerin also increased not only glutathione reductase but also peroxidase to the control level. And this compound increased amount of glutathione, an endogenous antioxidant. These results indicated that lonicerin isolated from L. japonica showed potent neuroprotective activity through the anti-oxidative pathway.

• 생약학회지
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• 제53권1호
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• pp.1-7
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• 2022

In the previous study, we reported that luteolin isolated from Lonicera japonica methanolic extract had potent neuroprotective activities in neuronal cell death injured by excessive glutamate. In this study, we tried to confirm the neuroprotective activities of luteolin in glutamate injured HT22 cells and establish mechanisms of neuroprotective action of luteolin. We used HT22 cell death injured by glutamate as a bioassay system. Luteolin decreased reactive oxygen species increased by excessive glutamate treatment in HT22 cells. Also, Ca²⁺ concentration was decreased by luteolin treatment. Luteolin made mitochondrial membrane potential maintain to normal condition. It also increased not only glutathione reductase but also peroxidase to the control level. And it increased amount of glutathione, an endogenous antioxidant. These results suggested that luteolin isolated from L. japonica showed potent neuroprotective activity through the anti-oxidative pathway.

• 생명과학회지
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• 제34권1호
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• pp.37-47
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• 2024

Fun14 도메인 함유 단백 1(Fun14 domain-containing protein 1, FUNDC1)은 미토콘드리아 외막에 존재하는 단백질로, 미토콘드리아의 마이토파지(mitophage) 기전 조절에 관여하는 것으로 알려져 있다. 본 연구에서는 해마 뉴런 기원의 HT-22 세포에서 아밀로이드 베타 펩티드(A_β)에 의한 미토콘드리아와 세포 손상 과정에서 FUNDC1의 개재 가능성과 역할을 조사하였다. HT-22 세포에서 A_β를 처리하면 처리 시간에 의존적으로 FUNDC1의 발현 감소가 관찰되었다. 또한 MTT 환원능과 세포 내 ATP 농도, 미토콘드리아 막전압의 감소, 반응성 산소종의 생성과 미토콘드리아 Ca²⁺ 부하의 증가 등 미토콘드리아의 기능적 손상을 나타내는 지표들의 변화와 함께 세포사멸의 증가가 관찰되었다. FUNDC1의 발현을 일시적으로 차단한 세포군에서도 미토콘드리아의 기능적 손상을 나타내는 지표 변화와 세포사멸의 증가가 관찰되었다. 반면에 FUNDC1을 일시적으로 과발현시킨 세포군에서는 A_β 처리에 의한 미토콘드리아 손상과 세포 사멸이 유의하게 억제되었다. 이와 같은 결과들은 A_β에 의한 미토콘드리아와 세포 손상 기전에 FUNDC1이 중요하게 관여할 가능성을 시사한다.