• Archives of Pharmacal Research
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• v.20 no.5
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• pp.510-512
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• 1997

The effects of noscapine a phthalide isoquinoline alkaloid, on dopamine biosynthesis and tyrosine hydroxylase (TH) activity in PC12 cells were investigated. Noscapine showed 74.6% inhibition on dopamine content in PC12 cells at a concentration of $20{\mu}M.$ $IC_{50}$ of noscapine was $6.8{\mu}M.$ TH activity was inhibited by the treatment of noscapine in PC12 cells (20.9% inhibition at 20 .mu.M). Therefore, the inhibition of TH activity by noscapine might be involved in at least one component of the reduction of dopamine biosynthesis in PC12 cells.

• Korean Journal of Pharmacognosy
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• v.30 no.1
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• pp.79-83
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• 1999

The effects of coralyne, a protoberberine isoquinoline compound, on dopamine biosynthesis in PC12 cells were investigated. Coralyne decreased the dopamine content dose-dependently $(46.3%\;inhibition\;at\;20\;{\mu}M\;for\;24 hr).$ Dopamine content was lowered at 6 hr and reached minimal level at 24 hr after exposure to coralyne at $20\;{\mu}M.$ The decreased dopamine level was maintained up to 48 hr and recovered to the control level at about 72 hr. Tyrosine hydroxylase, the rate-limiting enzyme in the catecholamine biosynthesis, was also inhibited at $20\;{\mu}M\;of\;coralyne$ by 16.1% relative to control. These results suggest that the inhibition of tyrosine hydroxylase by coralyne with a single treatment might be partially contributed to the decrease in dopamine content in PC12 cells.

• Korean Journal of Pharmacognosy
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• v.41 no.3
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• pp.221-226
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• 2010

The effects of sesamin on dopamine biosynthesis in PC12 cells were investigated. Sesamin at concentration ranges of 20-75 ${\mu}M$ significantly increased intracellular dopamine levels and tyrosine hydroxylase (TH) activities at 24 h: 50 ${\mu}M$ sesamin increased dopamine levels to 132% and TH activities to 128% of control levels. Sesamin (50 ${\mu}M$) induced the phosphorylation of TH, cyclic AMP-dependent protein kinase (PKA) and cyclic AMP-response element binding protein (CREB) for 0.5-24 h. Sesamin (50 ${\mu}M$) also increased the mRNA levels of TH and CREB for 3-24 h. In addition, sesamin (50 ${\mu}M$) associated with L-DOPA (50 and 100 ${\mu}M$) further increased the intracellular levels of dopamine for 24 h compared to L-DOPA alone. These results suggest that sesamin enhances dopamine biosynthesis and L-DOPA-induced increase in dopamine levels by inducing TH activity and TH gene expression, which is mediated by PKA-CREB systems in PC12 cells. Therefore, sesamin could serve as an adjuvant phytonutrient for neurodegenerative diseases.

• Natural Product Sciences
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• v.20 no.4
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• pp.296-300
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• 2014

The present study investigated the effects of (-)-sesamin on dopamine biosynthesis in PC12 cells. Treatment with (-)-sesamin (25 and $50{\mu}M$) increased intracellular dopamine levels and enhanced L-DOPA-induced increase in dopamine levels in PC12 cells. (-)-Sesamin (25 and $50{\mu}M$) also induced the phosphorylation of cyclic AMP-dependent kinase A (PKA), cyclic AMP-response element binding protein (CREB) and tyrosine hydroxylase (TH) in PC12 cells. These results suggest that (-)-sesamin induces dopamine biosynthesis via the PKA-CREB-TH pathways in PC12 cells. (-)-Sesamin needs to be studied further to serve as an adjuvant phytonutrient in neurodegenerative disease.

• Natural Product Sciences
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• v.24 no.2
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• pp.99-102
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• 2018

This study investigated the effects of ombuoside, a flavonol glycoside, on dopamine biosynthesis in PC12 cells. Ombuoside at concentrations of 1, 5, and $10{\mu}M$ increased intracellular dopamine levels at 1 - 24 h. Ombuoside (1, 5, and $10{\mu}M$) also significantly increased the phosphorylation of tyrosine hydroxylase (TH) (Ser40) and cyclic AMP-response element binding protein (CREB) (Ser133) at 0.5 - 6 h. In addition, ombuoside (1, 5, and $10{\mu}M$) combined with L-DOPA (20, 100, and $200{\mu}M$) further increased intracellular dopamine levels for 24 h compared to L-DOPA alone. These results suggest that ombuoside regulates dopamine biosynthesis by modulating TH and CREB activation in PC12 cells.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.105-110
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• 2006

The effects of tributyltin acetate (TBTA), one of the endocrine-disrupting organotin compounds, on dopamine biosynthesis in PC12 cells were investigated. Treatment of PC12 cells with TBTA at $0.05\sim0.25{\mu}M$ significantly decreased the intracellular dopamine content in a concentration-dependent manner ($IC_{50}$ value, $0.17{\mu}M$). Under these conditions, tyrosine hydroxylase (TH) activity and TH mRNA level were also decreased by $0.1{\mu}M$ TBTA at 24 h, and recovered there-after. In addition, treatment with L-DOPA at 20 and $50 {\mu}M$ increased the intracellular dopamine content in PC12 cells and the increase in dopamine content by L-DOPA was significantly abolished by TBTA at $0.1\sim0.2{\mu}M$. These results indicate that TBTA at $0.1\sim0.2{\mu}M$ causes the decrease in the basal dopamine content and abolishes the increase in dopamine content in L-DOPA-treated cells in part by the inhibition of TH gene expression and activity.

• Korean Journal of Pharmacognosy
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• v.29 no.4
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• pp.265-270
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• 1998

The effects of MeOH extracts of ninety kinds of medicinal herbs on dopamine content in PC12 cells were investigated. Among them, the MeOH extracts at a concentration of $40\;{\mu}g/ml$ of Symplocarpus renifolius, Adenocaulon himalaicum and Mosla punctulata decreased $38.5{\sim}60.0%$ of dopamine content. Tyrosine hydroxylase, the rate-limiting enzyme of the catecholamine biosynthesis, was inhibited by the treatment of the MeOH extracts of Symplocarpus renifolius, Adenocaulon himalaicum and Mosla punctulata ($19.9{\sim}31.3%$ inhibition at $40\;{\mu}g/ml$). These results suggested that these bioactive herbal medicines exhibited partially an inhibitory effect on dopamine biosynthesis by the reduction of tyrosine hydroxylase activity in PC12 cells.

• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.55-59
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• 2003

The effects of liriodenine, an aporphine isoquinoline alkaloid, on dopamine content in PCl2 cells were investigated. Treatment of PC12 cells with liriodenine decreased dopamine content in a dose-dependent manner (33.6% inhibition at $10\;{\mu}M$ for 12 h). The $IC_{50}$ in value of liriodenine was $8.4\;{\mu}M$. Dopamine content decreased at 3 h and reached a minimal level at 12 h after the exposure to liriodenine. Under these conditions, the activities of tyrosine hydroxylase and aromatic L-amino acid decarboxylase were also inhibited at $10\;{\mu}M$ of liriodenine by 10.1% and 20.2% relative to control, respectively. In addition, liriodenine inhibited the increase in dopamine content induced by L-DOPA Treatments $(50-100\;{\mu}M)$ in PC12 cells. These results suggest that liriodenine inhibited dopamine biosynthesis and L-DOPA-induced increase in dopamine content by reducing the activities of tyrosine hydroxylase and aromatic L- amino acid decarboxylase in PC12 cells.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.79.3-80
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• 2003

The effects of anonaine, an aporphine isoquinoline alkaloid, on dopamine biosynthesis and L-DOPA-induced neurotoxicity in PC12 cells were investigated. Treatment of PC12 cells with 0.05 ${\mu}$M anonaine showed a significant inhibition of dopamine content. The IC$\sub$50/ value of anonaine was 0.05 ${\mu}$M. Under the same conditions, 0.05 ${\mu}$M anonaine also inhibited tyrosine hydroxylase (TH) activity at 24 h (62.0% inhibition of the control level). TH mRNA levels were also decreased by the treatment with anonaine. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.85.2-85.2
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• 2003

In vivo aromatic ${\beta}$-carbolines, such as harman and norharman, may easily be formed by cyclization of indoleamines with e.g. aldehydes. Because of the structural similarity to MPTP, ${\beta}$-carbolines have been proposed as endogenous toxins. In this study, we have investigated the effects of harman and norharman on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells. Treatment of PC12 cells with harman and norharman showed 48.8% and 49.5% inhibition of dopamine content at a concentration of 20 ${\mu}$M and 100 ${\mu}$M for 48h. (omitted)