Huang Shelley H, Duke Rujee K, Chebib Mary, Sasaki Keiko, Wada Keiji, Johnston Graham A R
Adrien Albert Laboratory of Medicinal Chemistry, Department of Pharmacology, Faculty of Medicine, The University of Sydney, Sydney, NSW 2006, Australia.
Eur J Pharmacol. 2004 Jun 28;494(2-3):131-8. doi: 10.1016/j.ejphar.2004.04.051.
Ginkgolides A, B, and C are diterpene trilactones and active constituents of the 50:1 Ginkgo biloba leaf extract widely used in the symptomatic treatment of mild to moderate dementia. Using the two-electrode voltage clamp methodology, these ginkgolides were found to be moderately potent antagonists at recombinant human alpha(1)beta(2)gamma(2L) GABA(A) receptors expressed in Xenopus oocytes. Ginkgolides A, B, and C inhibited the direct action of gamma-aminobutyric acid (GABA) with K(i) values of 14.5+/-1.0, 12.7+/-1.7, and 16.3+/-2.4 microM respectively. Antagonism by these ginkgolides at alpha(1)beta(2)gamma(2L) GABA(A) receptors appears to be noncompetitive as indicated by the nonparallel right shift and reduced maximal GABA response in their GABA concentration-effect curves.
银杏内酯A、B和C是二萜三内酯，是广泛用于轻至中度痴呆症状治疗的50:1银杏叶提取物的活性成分。采用双电极电压钳方法，发现这些银杏内酯是非洲爪蟾卵母细胞中表达的重组人α(1)β(2)γ(2L)GABA(A)受体的中度有效拮抗剂。银杏内酯A、B和C抑制γ-氨基丁酸（GABA）的直接作用，其抑制常数（K(i)）值分别为14.5±1.0、12.7±1.7和16.3±2.4微摩尔。这些银杏内酯对α(1)β(2)γ(2L)GABA(A)受体的拮抗作用似乎是非竞争性的，这在它们的GABA浓度-效应曲线中表现为非平行右移和最大GABA反应降低。
