• 약학회지
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• 제42권2호
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• pp.170-174
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• 1998

The effects of bulbocapnine, an aporphine isoquinoline alkaloid, on dopamine content in PC12 cells were investigated. Bulbocapnine decreased the dopamine content dose-dependentl y (39.2% inhibition at 2O${\mu}$M for 24 hr). The $IC_{50}$ value of bulbocapnine was 22.7${\mu}$M. Dopamine content was lowered at 6 hr after exposure to bulbocapnine. And then, the decreased dopamine level was almost maintained at 36 hr and recovered to the control level at about 60 hr. Tyrosine hydroxylase, the rate limiting enzyme in the catecholamine blosynthetic pathway, was also inhibited at 20${\mu}$M of bulbocapnine by 23.1% relative to control. We, therefore, hypothesized that the inhibition of tyrosine hydroxylase by bulbocapnine with a single treatment might be partially contributed to the decrease in dopamine content in PC12 cells.

• 약학회지
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• 제50권2호
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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.

• 생약학회지
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• 제30권1호
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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.

• 약학회지
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• 제49권2호
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• pp.156-161
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• 2005

Tetrahydropapaveroline (THP) at 5-15 ${\mu}$M has been found to induce L-DOPA-induced oxidative apoptosis in PC12 cells. In this study, the inhibitory effects of THP on dopamine bios ynthesis in PC12 cells and tyrosine hydroxylase (TH) activity in bovine adrenal were investigated. Treatment of PC12 cells with THP at 2.5-10 ${\mu}$M significantly decreased the intracellular dopamine content in a concentration-dependent manner (18.3% inhibition at 10 ${\mu}$M THP). In these conditions, TH activity was markedly inhibited by the treatment with THP at 2.5-10 ${\mu}$M in PC12 cells (23.4% inhibition at 10 $\mu$ M THP). In addition, THP had an inhibitory effect on bovine adrenal TH activity IC50 value, 153.9${\mu}$M). THP exhibited uncompetitive inhibition on bovine adrenal TH activity with a substrate L-tyrosine with the KI value of 0.30 mM. Treatment with L-DOPA at 20~50 ${\mu}$M increased the intracellular dopamine content in PC12 cells, and the increase in dopamine content by L-DOPA was inhibited in part when THP at non-cytotoxic (5-10 ${\mu}$M) or cytotoxic (15${\mu}$M) concentrations was associated with L-DOPA (20 and 50 ${\mu}$M) for 24 h incubation. These results suggest that THP at 5-10${\mu}$M decreases the basal dopamine content and reduces the increased dopamine content induced by L-DOPA in part by the inhibition of TH activity, and that THP at 15${\mu}$M also decreases dopamine content by oxidative stress in PC12 cells.

• 생약학회지
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• 제34권1호통권132호
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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.

• Biomolecules & Therapeutics
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• 제16권2호
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• pp.106-112
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• 2008

The effects of harman and norharman on dopamine content and L-DOPA-induced cytotoxicity were investigated in PC12 cells. Harman and norharman decreased the intracellular dopamine content for 24 h. The $IC_{50}$ values of harman and norharman were 20.4 ${\mu}M$ and 95.8 ${\mu}M$, respectively. Tyrosine hydroxylase (TH) activity and TH mRNA levels were also decreased by 20 ${\mu}M$ harman and 100 ${\mu}M$ norharman. Under the same conditions, the intracellular cyclic AMP levels were decreased by harman and norharman. In addition, harman and norharman at concentrations higher than 80 ${\mu}M$ and 150 ${\mu}M$ caused cytotoxicity at 24 h in PC12 cells. Non-cytotoxic ranges of 10-30 ${\mu}M$ harman and 50-150 ${\mu}M$ norharman inhibited L-DOPA (20-50 ${\mu}M$)-induced increases of dopamine content at 24 h. Harman at 20-150 ${\mu}M$ and norharman at 100-300 ${\mu}M$ also enhanced LDOPA (20-100 ${\mu}M$)-induced cytotoxicity at 24 h. These results suggest that harman and norharman decrease dopamine content by reducing TH activity and aggravate L-DOPA-induced cytotoxicity in PC12 cells.

• 대한약리학회지
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• 제27권1호
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• pp.7-12
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• 1991

쥐(태령 14일) 뇌간 세포배양에서 발달과정에 따른 Tyrosine hydroxylase(TH) 활성 및 dopamine의 양적 증가를 전기화학 HPLC를 이용하여 측정하였다. TH 활성 및 dopamine의 양은 배양 7일까지 점차 증가하였다. 배양 7일째에 여러 약물들의 dopamine 대사에 대한 영향을 조사하였다. TH 억제제인 ${\alpha}-methyl-p-tyrosine$ 및 aromatic amiono acid decarboxylase 억제제인 NSD-1015는 효과적으로 dopamine을 고갈시켰다. Dopamine은 reserpine에 의해 고갈되었고, parglyine에 의해 증가되었다. 일주일 배양한 세포의 배양액에 tetrodotoxin$(0.1\;{\mu}M$)을 7일간 투여하였을 때 TH 활성은 현저히 감소하였다. 이상의 결과들은 배양세포의 dopamine 대사가 뇌 dopamine 대사를 충실히 반영함을 나타낸다. 뇌간 세포의 배양에서 HPLC-전기화학검출을 이용한 TH 활성 및 dopamine의 측정은 중추 dopamine계의 약리 및 독성 연구에 유용하리라 사료된다.

• Natural Product Sciences
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• 제10권3호
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• pp.104-108
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• 2004

Five lignans including gomisin N (1), wuweizisu C (2), gomisin L1 (3), (+)-deoxyschizandrin (4), and gomisin J (5) have been isolated from the fruits of Schizandra chinensis. The structures of the isolated compounds were elucidated by analyzing MS and NMR spectra. Effects of the compounds isolated in this study on the dopamine content in PC12 cells were investigated to evaluate their inhibitory effectiveness. The gomisin N, wuweizisu C, and gomisin J showed 25.4%, 39.8%, and 35.1 %, respectively, inhibition effect on dopamine content in PC12 cells at the concentration of $50\;{\mu}g/ml$.

• 생약학회지
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• 제29권4호
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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.

• Natural Product Sciences
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• 제10권3호
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• pp.119-123
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• 2004

The effects of BHSH on L-DOPA-induced increase in dopamine content in PC12 cells were investigated. L-DOPA treatment at $20\;or\;50\;{\mu}M$ increased dopamine content after both 24 and 48 h of incubation in PC12 cells. However, the co-treatments of BHSH $(10-50\;{\mu}M)$ with L-DOPA $(20\;or\;50\;{\mu}M)$ significantly inhibited the increase of dopamine content induced by L-DOPA. BHSH treatment at $10-50\;{\mu}M$ significantly inhibited basal aromatic L-amino acid decarboxylase (AADC) activity in a concentration-dependent manner at 15 min, and then AADC activity was rapidly recovered to the control level at about 2 h. These results indicate that the inhibition of AADC activity by BHSH was, in part, contributed to the early-stage decrease of dopamine content induced by LDOPA in PC12 cells. Taken together, it is proposed that the short-term inhibition of dopamine biosynthesis by BHSH was mediated by the regulation of tyrosine hydroxylace (TH).