Guo X, Wang L M, Liu J, Jin G Z
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China.
Zhongguo Yao Li Xue Bao. 1997 May;18(3):225-30.
To study the characteristics of tetrahydroprotoberberines (THPB) on dopamine D1 and D2 receptors and elucidate their structure-activity relationship.
Radioligand assay in vitro with a two-site model program analysis.
Four THPB with two hydorxyl groups on C2 and C9 or C2 and C10 exhibited RH and RL two binding sites to D1 receptors and guanosine triphosphate regulated the RH binding site of SPD and THPB-132A in competition assay, while eleven THPB including nonhydroxy-THPB, monohydroxy-THPB, and THPB with two hydroxyl groups attaching to C3 and C10 showed one binding site to D1 receptors under the same conditions. However, the tested eleven THPB all manifested one binding site to D2 receptors in competition assay, and the 2-hydroxy-THPB had the most potent affinity for D2 receptors.
Dihydroxy-THPB with two hydroxyl groups attaching to C2 and C9 or C2 and C10 possess the intrinsic activity of agonist to D1 receptors, while the other THPB do not. The tested eleven THPB all are the antagonists of D2 receptors.
研究四氢原小檗碱（THPB）对多巴胺D1和D2受体的作用特点，阐明其构效关系。
采用体外放射性配体结合实验及两点模型程序分析。
在C2和C9或C2和C10位有两个羟基的四种THPB对D1受体表现出RH和RL两个结合位点，在竞争实验中，鸟苷三磷酸调节SPD和THPB - 132A的RH结合位点；而包括非羟基THPB、单羟基THPB以及在C3和C10位有两个羟基的THPB在内的十一种THPB在相同条件下对D1受体表现出一个结合位点。然而，在竞争实验中，所检测的十一种THPB对D2受体均表现出一个结合位点，且2 - 羟基THPB对D2受体具有最强的亲和力。
在C2和C9或C2和C10位有两个羟基的二羟基THPB对D1受体具有激动剂的内在活性，而其他THPB则没有。所检测的十一种THPB均为D2受体拮抗剂。
