title: Effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells.
abstract: The effects of catalpalactone on dopamine biosynthesis and L-DOPA-induced cytotoxicity in PC12 cells were investigated. Catalpalactone at 5-30μM decreased intracellular dopamine content with the IC(50) value of 22.1μM. Catalpalactone at 5-20μM, but not 30μM, did not alter cell viability. Catalpalactone at 20μM inhibited tyrosine hydroxylase (TH) and aromatic-l-amino acid decarboxylase (AADC) activities. Catalpalactone also decreased cyclic AMP levels and inhibited TH phosphorylation. In addition, catalpalactone at 20μM reduced the increases in dopamine levels induced by L-DOPA (20-50μM). Catalpalactone (5-30μM) associated with L-DOPA (50-100μM) enhanced L-DOPA-induced cytotoxicity at 48h, which was prevented by N-acetyl-l-cysteine. These results suggest that catalpalactone inhibited dopamine biosynthesis by reducing TH and AADC activities and enhanced L-DOPA-induced cytotoxiciy in PC12 cells.
authors.affiliation: College of Pharmacy, Chungbuk National University, Cheongju 361-763, Republic of Korea.
authors.forename: Hai Shan
authors.initials: HS
authors.lastname: Huang
authors.forename: Xiang Hua
authors.initials: XH
authors.lastname: Han
authors.forename: Bang Yeon
authors.initials: BY
authors.lastname: Hwang
authors.forename: Jae In
authors.initials: JI
authors.lastname: Park
authors.forename: Se Kuel
authors.initials: SK
authors.lastname: Yoo
authors.forename: Hak Ju
authors.initials: HJ
authors.lastname: Lee
authors.forename: Sung Cil
authors.initials: SC
authors.lastname: Lim
authors.forename: Myung Koo
authors.initials: MK
authors.lastname: Lee