Theory for the impact of basal turnover on dopamine clearance kinetics in the rat striatum after medial forebrain bundle stimulation and pressure ejection.
Theory for the impact of basal turnover on dopamine clearance kinetics in the rat striatum after medial forebrain bundle stimulation and pressure ejection.
复制标题
内侧前脑束刺激和压力喷射后基础周转对大鼠纹状体多巴胺清除动力学影响的理论。
DOI：
10.1111/j.1471-4159.2005.03265.x
复制
发表时间：
2005
影响因子：
4.7
通讯作者：
Motzko,ChristinaM
中科院分区：
文献类型：
--
作者：
Michael,AdrianC;Borland,LauraM;MitalaJr,JosephJ;Willoughby,BridgetM;Motzko,ChristinaM
Although microdialysis measurements suggest that extracellular dopamine concentrations in the rat striatum are in the low nanomolar range, some recent voltammetry studies suggest that the concentration may be considerably higher, perhaps in the micromolar range. The presence of such high dopamine levels in the extracellular space has to be rationalized with the rapid, linear clearance of extracellular dopamine observed after electrical stimulation of the medial forebrain bundle. Kinetic analysis of dopamine clearance after evoked release suggests that the basal extracellular dopamine concentration is below theKMof dopamine uptake, which is near 0.2 µm. However, dopamine clearance after pressure ejection of dopamine into the rat striatum is slow and non‐linear, which may alternatively be a sign that basal dopamine release is only slightly slower than the maximal velocity of dopamine uptake,Vmax. A high basal extracellular dopamine concentration would exist if basal dopamine release were only slightly slower than theVmaxof uptake. This report introduces a new kinetic analysis of dopamine uptake that sheds light on the possible source of the different clearance rates observed following evoked dopamine release and dopamine pressure ejection. Furthermore, the analysis rationalizes the rapid dopamine clearance after evoked release with the possibility that basal extracellular dopamine levels are above theKMof the transporter.
