Bilobalide, a sesquiterpene trilactone from Ginkgo biloba, is an antagonist at recombinant alpha1beta2gamma2L GABA(A) receptors.
Bilobalide, a sesquiterpene trilactone from Ginkgo biloba, is an antagonist at recombinant alpha1beta2gamma2L GABA(A) receptors.
复制标题
DOI：
--
复制
发表时间：
2003
影响因子：
5
通讯作者：
Shelley H. Huang;R. Duke;M. Chebib;K. Sasaki;K. Wada;G. Johnston
中科院分区：
文献类型：
--
作者：
Shelley H. Huang;R. Duke;M. Chebib;K. Sasaki;K. Wada;G. Johnston
倍半萜三内酯白果内酯是50：1银杏叶提取物的活性成分之一，广泛用于增强记忆和学习。银杏内酯被发现拮抗γ-氨基丁酸（GABA）对重组α（1）β（2）γ（2L）GABA（A）受体的直接作用。用双电极电压钳技术研究了银杏内酯对GABA直接作用于非洲爪蟾卵母细胞表达的α（1）β（2）γ（2L）GABA（A）受体的影响，并与经典的GABA（A）受体竞争性拮抗剂荷包牡丹碱和非竞争性拮抗剂印防己毒素的作用进行了比较。白果内酯（IC（50）=4.6+/-0.5 microM）与荷包牡丹碱和苦毒宁（IC（50）分别为2.0+/-0.1和2.4+/-0.5 microM）在α（1）β（2）γ（2L）GABA（A）受体上对40 microM GABA（GABA EC（50））的效力几乎相同。虽然白果内酯和苦毒素明显是非竞争性拮抗剂，但白果内酯的效力在高GABA浓度下降低，表明存在竞争性拮抗作用。
The sesquiterpene trilactone bilobalide is one of the active constituents of the 50:1 Ginkgo biloba leaf extract widely used to enhance memory and learning. Bilobalide was found to antagonise the direct action of gamma-aminobutyric acid (GABA) on recombinant alpha(1)beta(2)gamma(2L) GABA(A) receptors. The effect of bilobalide on the direct action of GABA at alpha(1)beta(2)gamma(2L) GABA(A) receptors expressed in Xenopus laevis oocytes using two-electrode voltage-clamp method was evaluated and compared with the effects of the classical GABA(A) receptor competitive antagonist bicuculline and noncompetitive antagonist picrotoxinin. Bilobalide (IC(50)=4.6+/-0.5 microM) was almost as potent as bicuculline and pictrotoxinin (IC(50)=2.0+/-0.1 and 2.4+/-0.5 microM, respectively) at alpha(1)beta(2)gamma(2L) GABA(A) receptors against 40 microM GABA (GABA EC(50)). While bilobalide and picrotoxinin were clearly noncompetitive antagonists, the potency of bilobalide decreased at high GABA concentrations suggesting a component of competitive antagonism.