Audinot V, Lochon S, Newman-Tancredi A, Lavielle G, Millan M J
Institut de Recherches Servier, Department of Psychopharmacology, Croissy-sur-Seine, France.
Eur J Pharmacol. 1997 May 30;327(2-3):247-56. doi: 10.1016/s0014-2999(97)89668-9.
Native brain 5-HT1B/1D) receptors were studied using the novel antagonist, [3H]GR 125,743 (N-[4-methoxy-3-(4-methylpiperazin-1-yl)phenyl]-3-methyl-4-(4-pyri dyl)benzamide). In guinea-pig striatal membranes, [3H]GR 125,743 displayed rapid association (t1/2 = 4.5 min), high (90%) specific binding and high affinity (K(d) = 0.29 nM), although B(max) values (fmol/mg protein) varied according to brain region-striatum: 199; frontal cortex: 89; hippocampus: 79; cerebellum: 26. In frontal cortex, the B(max) determined with [3H]5-CT ([3H]carboxamidotryptamine) was significantly higher (178; P < 0.05), suggesting that it also labels other binding sites. In striatal membranes, guanylylimidodiphosphate (GppNHp) inhibited [3H]5-CT but not [3H]GR 125,743 binding, suggesting that the latter has antagonist properties. Nevertheless, in competition binding experiments, the pK(i) values obtained with [3H]GR 125,743 and [3H]5-CT for 20 serotonergic ligands, including L 694,247 (2-[5-[3-(4-methylsulphonylamino)benzyl-1,2,4-oxadiazol-5-yl ]-1H-indole-3-yl]ethylamine), GR46,611 (3-[3-(2-dimethylamino-ethyl)-1H-indol-6-yl]-N-(4-methoxybenzyl)acrylami de), sumatriptan and alniditan, were highly correlated (r = 0.99). Ketanserin and ritanserin showed low affinity for [3H]GR 125,743 binding to guinea-pig striatal sites (K(i) = 12600 and 369 nM), suggesting that 5-HT1B (rather than 5-HT1D) receptors are predominantly labelled in this tissue. The present data indicate that [3H]GR 125,743 is a useful tool for studying native 5-HT1B/1D receptors.
使用新型拮抗剂[3H]GR 125,743（N-[4-甲氧基-3-(4-甲基哌嗪-1-基)phenyl]-3-甲基-4-(4-吡啶基)苯甲酰胺）对天然脑5-HT1B/1D受体进行了研究。在豚鼠纹状体膜中，[3H]GR 125,743表现出快速结合（t1/2 = 4.5分钟）、高（90%）特异性结合和高亲和力（K(d) = 0.29 nM），尽管B(max)值（fmol/mg蛋白质）因脑区而异——纹状体：199；额叶皮质：89；海马体：79；小脑：26。在额叶皮质中，用[3H]5-CT（[3H]羧酰胺色胺）测定的B(max)显著更高（178；P < 0.05），表明它还标记其他结合位点。在纹状体膜中，鸟苷酰亚胺二磷酸（GppNHp）抑制[3H]5-CT但不抑制[3H]GR 125,743结合，表明后者具有拮抗剂特性。然而，在竞争结合实验中，用[3H]GR 125,743和[3H]5-CT对20种血清素能配体（包括L 694,247（2-[5-[3-(4-甲基磺酰氨基)苄基-1,2,4-恶二唑-5-基]-1H-吲哚-3-基]乙胺）、GR46,611（3-[3-(2-二甲基氨基乙基)-1H-吲哚-6-基]-N-(4-甲氧基苄基)丙烯酰胺）、舒马曲坦和阿尼地坦）获得的pK(i)值高度相关（r = 0.99）。酮色林和利坦色林对[3H]GR 125,743与豚鼠纹状体位点的结合表现出低亲和力（K(i) = 12600和369 nM），表明在该组织中主要标记的是5-HT1B（而非5-HT1D）受体。目前的数据表明，[3H]GR 125,743是研究天然5-HT1B/1D受体的有用工具。
