Department of Neurology, St. Joseph Hospital Berlin-Weißensee, Gartenstr. 1, 13088, Berlin, Germany.
Thanares GmbH, Hermannswerder 14, 14473, Potsdam, Germany.
J Neural Transm (Vienna). 2019 Nov;126(11):1417-1420. doi: 10.1007/s00702-019-02057-1. Epub 2019 Aug 8.
Peaks and troughs of levodopa in plasma contribute to pulsatile postsynaptic dopamine receptor stimulation in patients with Parkinson's disease. Measurement of levodopa plasma levels mostly only considers the total levodopa plasma concentration. Objectives were to determine bound, free, and total plasma levodopa and to investigate their correlations to each other. We employed reversed-phase high-performance liquid chromatography combined with electrochemical detection. Bound levodopa was computed as difference between total and free L-dopa values. Close correlations between free and total (R = 0.93, p < 0.0001), bound and total (R = 0.91, p < 0.0001) plasma levodopa appeared. A considerable variability of levodopa concentrations occurred. The ratio between bound and free levodopa did not differ in patients with a higher and lower oral daily levodopa dosing. Free, bound, and total levodopa plasma levels are closely related. Estimation of the total levodopa level only seems to be meaningful.
血浆中左旋多巴的峰谷变化导致帕金森病患者突触后多巴胺受体的脉冲式刺激。左旋多巴血浆水平的测量大多只考虑总左旋多巴血浆浓度。目的是确定结合型、游离型和总血浆左旋多巴，并研究它们之间的相关性。我们采用反相高效液相色谱法结合电化学检测。结合型左旋多巴通过总左旋多巴值减去游离左旋多巴值计算得出。游离和总（R = 0.93，p < 0.0001）、结合和总（R = 0.91，p < 0.0001）的血浆左旋多巴之间存在密切的相关性。左旋多巴浓度的变异性很大。每日口服左旋多巴剂量较高和较低的患者之间，结合型和游离型左旋多巴的比值没有差异。游离型、结合型和总血浆左旋多巴水平密切相关。仅估计总左旋多巴水平似乎才有意义。
