Villeneuve A, Berlan M, Lafontan M, Montastruc J L
Comp Biochem Physiol C Comp Pharmacol Toxicol. 1985;81(1):181-7. doi: 10.1016/0742-8413(85)90112-4.
The dog platelet alpha-adrenergic receptor was characterized using [3H]clonidine and [3H]yohimbine. The binding of both radioligands was rapid and reversible at 25 degrees C; saturation and kinetic experiments revealed a single population of binding sites. The number of [3H]yohimbine sites was 2-3-fold higher than the number of [3H]clonidine sites as reported in other tissues containing alpha2-adrenoceptors. The various alpha-agonists and antagonists displaced [3H]clonidine and [3H]yohimbine with an order of potency indicating alpha2-adrenoceptor specificity. Neither (-)adrenaline nor clonidine infusions (0.5 micrograms/min/kg during 3 hr) modified the number of [3H]yohimbine and [3H]clonidine sites or the affinity of the ligands for the alpha2-sites of the dog platelet. Oral administration of clonidine (3 X 150 micrograms/day) did not alter the binding parameters of either ligand.
利用[3H]可乐定和[3H]育亨宾对犬血小板α-肾上腺素能受体进行了表征。在25℃时，两种放射性配体的结合迅速且可逆；饱和和动力学实验显示存在单一的结合位点群体。如在其他含有α2-肾上腺素能受体的组织中所报道的那样，[3H]育亨宾位点的数量比[3H]可乐定位点的数量高2至3倍。各种α-激动剂和拮抗剂以表明α2-肾上腺素能受体特异性的效价顺序取代了[3H]可乐定和[3H]育亨宾。静脉输注（0.5微克/分钟/千克，持续3小时）（-）肾上腺素或可乐定都没有改变犬血小板中[3H]育亨宾和[3H]可乐定位点的数量或配体对α2-位点的亲和力。口服可乐定（3×150微克/天）不会改变任何一种配体的结合参数。
