The flavone hispidulin, a benzodiazepine receptor ligand with positive allosteric properties, traverses the blood-brain barrier and exhibits anticonvulsive effects
作者:Dominique Kavvadias、Philipp Sand、Kuresh A Youdim、M Zeeshan Qaiser、Catherine Rice-Evans、Roland Baur、Erwin Sigel、Wolf-Dieter Rausch、Peter Riederer、Peter Schreier
DOI:10.1038/sj.bjp.0705828
日期:2004.7
The functional characterization of hispidulin (4′,5,7‐trihydroxy‐6‐methoxyflavone), a potent benzodiazepine (BZD) receptor ligand, was initiated to determine its potential as a modulator of central nervous system activity.
After chemical synthesis, hispidulin was investigated at recombinant GABAA/BZD receptors expressed by Xenopus laevis oocytes. Concentrations of 50 nM and higher stimulated the GABA‐induced chloride currents at tested receptor subtypes (α1−3,5,6β2γ2S) indicating positive allosteric properties. Maximal stimulation at α1β2γ2S was observed with 10 μM hispidulin. In contrast to diazepam, hispidulin modulated the α6β2γ2S‐GABAA receptor subtype.
When fed to seizure‐prone Mongolian gerbils (Meriones unguiculatus) in a model of epilepsy, hispidulin (10 mg kg−1 body weight (BW) per day) and diazepam (2 mg kg−1 BW per day) markedly reduced the number of animals suffering from seizures after 7 days of treatment (30 and 25% of animals in the respective treatment groups, vs 80% in the vehicle group).
Permeability across the blood–brain barrier for the chemically synthesized, 14C‐labelled hispidulin was confirmed by a rat in situ perfusion model. With an uptake rate (Kin) of 1.14 ml min−1 g−1, measurements approached the values obtained with highly penetrating compounds such as diazepam.
Experiments with Caco‐2 cells predict that orally administered hispidulin enters circulation in its intact form. At a concentration of 30 μM, the flavone crossed the monolayer without degradation as verified by the absence of glucuronidated metabolites.
British Journal of Pharmacology (2004) 142, 811–820. doi:10.1038/sj.bjp.0705828
飞斯丁(4′,5,7-三羟基-6-甲氧基黄酮),作为一种效力强大的苯二氮卓(BZD)受体配体,其功能特性研究被启动,以确定其作为中枢神经系统活性调节剂的潜力。在化学合成后,飞斯丁被研究于非洲爪蟾卵母细胞表达的重组GABAA/BZD受体。50 nM及以上的浓度刺激了测试受体亚型(α1−3,5,6β2γ2S)的GABA诱导的氯电流,表明其正向变构特性。在α1β2γ2S受体中,10 μM的飞斯丁观察到最大刺激。与地西泮不同,飞斯丁调节了α6β2γ2S-GABAA受体亚型。当应用于癫痫模型中的易抽搐蒙古沙鼠(Meriones unguiculatus)时,飞斯丁(10 mg/kg体重/天)和地西泮(2 mg/kg体重/天)显著减少了治疗7天后出现抽搐的动物数量(治疗组分别为30%和25%,而对照组为80%)。通过大鼠原位灌流模型,证实了化学合成的、14C标记的飞斯丁穿过血脑屏障的能力。其摄取速率(Kin)为1.14 ml/min/g,测量值接近地西泮等高穿透化合物的值。使用Caco-2细胞进行的实验预测,口服的飞斯丁以完整形式进入循环系统。在30 μM浓度下,黄酮类化合物通过单层细胞未发生降解,这一点通过缺乏葡萄糖醛酸化代谢物得以验证。British Journal of Pharmacology (2004) 142, 811–820. doi:10.1038/sj.bjp.0705828