Abstract
3H-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 10 μmol·L-1 clonidine (K2:0.104 min-1). 3H-CLO saturation experiments indicated a single class of site with a K(D) of 5.87 ± 1.13 nmol·L-1 and B(max) 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 binding of 3H-CLO to α2-adrenoceptors and the K1 value of quercetin for α2-adrenoceptors was 5.73 ± 1.58 μmol·L-1.
Original language | English (US) |
---|---|
Pages (from-to) | 383-386 |
Number of pages | 4 |
Journal | Chinese Pharmacological Bulletin |
Volume | 11 |
Issue number | 5 |
State | Published - 1995 |
Keywords
- brain
- clonidine
- competitive binding
- quercetin
- radioligand assay
- α-adrenoceptors
ASJC Scopus subject areas
- Pharmacology