Ginkgolides, diterpene trilactones of Ginkgo biloba, as antagonists at recombinant a1h2g2L GABAA receptors
نویسندگان
چکیده
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 a1h2g2L GABAA receptors expressed in Xenopus oocytes. Ginkgolides A, B, and C inhibited the direct action of g-aminobutyric acid (GABA) with Ki values of 14.5F 1.0, 12.7F 1.7, and 16.3F 2.4 AM respectively. Antagonism by these ginkgolides at a1h2g2L GABAA receptors appears to be noncompetitive as indicated by the nonparallel right shift and reduced maximal GABA response in their GABA concentration–effect curves. D 2004 Elsevier B.V. All rights reserved.
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