摘要
用３Ｈ－可乐定分析大鼠大脑皮质细胞膜α２－肾上腺素能受体的特征，研究槲皮素对３Ｈ－可乐定结合的影响。３Ｈ－可乐定与大鼠大脑皮质细胞膜的结合是快速（Ｋ１：０．０２７Ｌ·ｎｍｏｌ－１·ｍｉｎ－１）、可逆（Ｋ２：０．１０４ｍｉｎ－１）的，有高度亲和力（ＫＤ：５．８７±１．１３ｎｍｏｌ·Ｌ－１）和可饱和性（Ｂｍａｘ：１６０±１０ｐｍｏｌ·ｇ－１，ｐｒ）。ｌ－可乐定、ｌ－肾上腺素、ｌ－去甲肾上腺素和ｌ－异丙肾上腺素等药物抑制３Ｈ－可乐定结合的效能顺序表明，大鼠大脑皮质细胞膜上３Ｈ－可乐定结合点为α２－肾上腺素能受体。１ｎｍｏｌ·Ｌ－１～１ｍｍｏｌ·Ｌ－１槲皮素竞争抑制３Ｈ－可乐定与大鼠大脑皮质细胞膜α２－肾上腺素能受体结合，Ｋｉ值为５．７３±１．５８μｍｏｌ·Ｌ－１。
H-clonidine(3H-CLO)was used to label α2-adrenoceptors in rat cerebral cortex and the effects of quercetin on α2-adrenoceptors in rat cerebral cortex were investigated. The binding of 3H-CLO to rat Cerebral cortex was rapid (K1:0.027 L· nmol-1·min-1) and readily reversed by 10μmol·L-1 clonidine(K2:0.104 min-1).3H-CLO saturation experiments indicated a single class of with a KD of 5.87±1.13nmol· L-1 and Bmax of 160±10 fmol·(mg protein)-1. The competition experiments with l-clonidine,l-epinephrine,l-norepinephrine and l-isoproterenol etc suggested that 3H-CLO binding site was α2-adrenoceptors. Quercetin(1 nmol·L-1～1 mmol·L-1) competitively inhibited the hinding of 3H-CLO to α2-adrenoceptors and the K1 value of quercetin for α2-adrenoceptors was 5.73×1.58 μmol·L-1.
出处
《中国药理学通报》
CAS
CSCD
北大核心
1995年第5期383-386,共4页
Chinese Pharmacological Bulletin
关键词
槲皮素
肾上腺素能受体
脑皮质细胞膜
quercetin
clonidine
brain
α_2-adrenoceptors
radioligand assay
competitive binding
