Effects of levodopa and dopamine on the number and function of dopamine transporter
Levodopa and dopamine were toxic to D8 cells and dopamine binding sites and the function of DAT was improved after the use of levodopa at an optimal dosage.
Abstract
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. \[