Ascorbic acid inhibits 125I-SCH 23982 binding but increases the affinity of dopamine for D1 dopamine receptors.
Ascorbic acid inhibits 125I-SCH 23982 binding but increases the affinity of dopamine for D1 dopamine receptors.
复制标题
抗坏血酸抑制 125I-SCH 23982 结合，但增加多巴胺对 D1 多巴胺受体的亲和力。
DOI：
10.1046/j.1471-4159.1994.63062093.x
复制
发表时间：
1994
影响因子：
4.7
通讯作者：
Sidhu,A
中科院分区：
文献类型：
--
作者：
Kimura,K;Sidhu,A
Effects of ascorbic acid (AA) on125I‐SCH 23982 binding to D1dopaminergic receptors in membrane preparations from rat striatum were investigated. AA in the range of 0.03 µM–0.33 mMinhibited 75% of specific binding of125I‐SCH 23982 in a dose‐dependent manner. At higher concentrations, this inhibition of binding activity by AA was less potent, and 3.3 mMAA inhibited only 30% of specific binding. Reduced glutathione did not alter the inhibition of binding by 0.33 mMAA, but reduced the inhibition by 3.3 mMAA to 8% of specific binding. The loss of specific binding by AA was rescued by 1 mMEDTA, an inhibitor of lipid peroxidation. In the absence of AA, competition experiments with the agonist, dopamine, revealed the presence of high‐affinity (Kh= 224.9 ± 48.9 nM) and low‐affinity (Kl= 21,100 ± 2,400 nM) binding sites. Although the maximum binding of125I‐SCH 23982 decreased to 40% without affecting theKDvalue in the presence of 1.67 mMAA, the value of the high‐affinity site for dopamine was increased (Kh= 23.3 ± 9.4 nM) and that of the low‐affinity site was decreased (Kl= 136,800 ± 40,900 nM). These results suggest that AA may affect D1dopamine receptor function by lipid peroxidation, competition with dopamine for low‐affinity sites, and reduced oxidation of dopamine.
