Wang L M, Zhang X X, Jin G Z
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China.
Zhongguo Yao Li Xue Bao. 1997 Mar;18(2):143-6.
To compare the actions of tetrahydroprotoberberines (THPB) on dopamine (DA) D2 receptors in the ventral tegmental area (VTA) of rat.
Extracellular single unit recording technique was used in i.v. gallamine-paralyzed rats.
Eleven THPB analogs tested completely attenuated the apomorphine (Apo, 20 micrograms.kg-1)-induced inhibition on VTA DA cell firing activity. The OH group on C2 at THPB was linked with the reversal of Apo-induced inhibition. Their reversal potencies (ED50, microgram.kg-1) for D2 receptors were: THPB-143 (5.6) > SPD (8.5) > Iso (17.0) > THP (33) > THB (48) > THPB-18 (66) > THPB-1 (179) > THPB-19 (408) > THPB-126 (510) > THPB-104 (1019) > THPB-10 (4815).
Among these 11 THPB, the 2-hydroxyl-THPB (THPB-143) showed the strongest antagonistic action on D2 receptors.
比较四氢原小檗碱(THPB)对大鼠腹侧被盖区(VTA)多巴胺(DA)D2受体的作用。
采用细胞外单单位记录技术,对静脉注射加拉明麻痹的大鼠进行实验。
所测试的11种THPB类似物均完全减弱了阿扑吗啡(Apo,20微克·千克-1)诱导的对VTA多巴胺能细胞放电活动的抑制作用。THPB中C2位上的羟基与Apo诱导抑制作用的逆转有关。它们对D2受体的逆转效力(半数有效剂量,ED50,微克·千克-1)分别为:THPB-143(5.6)> 小檗胺(SPD,8.5)> 异粉防己碱(Iso,17.0)> 四氢小檗碱(THP,33)> 小檗碱(THB,48)> THPB-18(66)> THPB-1(179)> THPB-19(408)> THPB-126(510)> THPB-104(1019)> THPB-10(4815)。
在这11种THPB中,2-羟基-THPB(THPB-143)对D2受体表现出最强的拮抗作用。