摘要
目的 :了解左旋多巴和多巴胺对多巴胺转运体的影响。 方法 :通过体外永久表达大鼠多巴胺转运体(DAT)的CHO细胞 (CHO/DAT ,即D8细胞 )的培养 ,采用MTT细胞活性检测和流式细胞仪观察不同剂量左旋多巴和多巴胺对D8细胞的毒性作用 ;利用 [3H]WIN35 ,4 2 8结合率和 [3H]DA摄取率检测DAT的数量和功能。 结果 :左旋多巴和多巴胺不仅对D8细胞有毒性损害 ,呈剂量、时间依赖 (P <0 .0 1) ,还能使DAT数量明显减少 ,与剂量相关 (P <0 .0 1) ,一定剂量的左旋多巴 (2 0 0 μmol/L～ 1mmol/L)可增加细胞对 [3H]DA的摄取 ,而大剂量左旋多巴 (5mmol/L)则抑制DAT的功能 (P <0 .0 1)。左旋多巴和多巴胺呈剂量依赖性地促进细胞凋亡 (P <0 .0 1)。结论 :左旋多巴和多巴胺不仅对D8细胞有毒性损害 ,还能使DAT数量明显减少 ,DAT结合位点的减少比细胞活性的下降更明显。一定剂量左旋多巴可增强DAT的功能。
Objective: To observe the effects of levodopa and dopamine on the number and function of dopamine transporter (DAT).Methods: Based on the culture of the CHO/DAT cells(designated D8 cells, CHO cell lines stably expressing DAT), the possible cytotoxicity of levodopa and dopamine at different dosages on D8 cells was determined by MTT assay and flow cytometry. The effects of levodopa and dopamine on the number and function of DAT were assessed by isotope detection of \[ 3 H\] WIN35,428 binding and \[ 3 H\] DA uptake. Results: The concentration and time dependent decrease in cell viability and the concentration dependent increase in apoptotic cells were found following the exposure to levodopa and dopamine( P <0.01). Reduction in DAT binding sites was more significant than that in cell viability. The exposure to 200 μmol/L 1 mmol/L levodopa, but not 5 mmol/L levodopa,for 24 h increased \[ 3 H\] DA uptake. Conclusion: Levodopa and dopamine were toxic to D8 cells and dopamine binding sites. The function of DAT was improved after the use of levodopa at an optimal dosage. \[
基金
国家重点基础研究规划"脑功能和脑重大疾病的基础研究"项目 (G19990 5 40 0 8)
国家科委"九五"攻关项目 ( 96 90 6 0 5 0 8)
卫生部科学研究基金 ( 98 1 3 19)
上海市卫生系统百名跨世纪优秀学科带头人培养计划 ( 97BR0 0 1)资助项目
