Related Experiment Video
Updated: Sep 18, 2026

Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
Structure-activity studies with Ginkgo biloba extract constituents as receptor-gated chloride channel blockers and
S S Chatterjee1, E L Kondratskaya, O A Krishtal
1Department of Pharmacology, Research and Development, Dr. Willmar Schwabe GmbH & Co. KG, Postfach 41 09 29, 76209 Karlsruhe, Germany.
Abstract:
The constituents of Ginkgo biloba leaf extract, ginkgolides A, B, C and J are known as effective antagonists of platelet-activating factor (PAF). Here, we will demonstrate that these substances are also effective blockers of glycine-activated chloride channels in the hippocampal neurons of rat. As examined in several other voltage- and ligand-operated channels, this ginkgolide action is selective. The blocking action of all tested ginkgolides is use-dependent--they block open glycine-activated channels. The IC (50) values for saturating blocking action of ginkgolides B and C are 0.273 microM and 0.267 microM, respectively, while ginkgolides A and J are less effective--IC (50) values are 1.97 microM and 2.0 microM. Corresponding dose-response relationships are close to single-site binding isotherms. Another constituent of EGb 761, bilobalide, is a weak inhibitor of NMDA receptor-activated current. Its synthetic analogue, NV-31, demonstrates a weak facilitatory action on Gly-activated conductance. Novel findings have indicated the possibility that the unique modulating activity profiles of the EGb 761 (definition see editorial) constituents examined are due to their effects on the anion homeostasis of central neurons.
Related Concept Videos
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
Ligand-gated Ion Channels
Three Subfamilies of Ligand-gated Ion Channels
Ligand-gated ion channels fall into three subfamilies. The 'Cys-loop' includes the nicotinic acetylcholine receptors, γ-aminobutyric acid (GABA), glycine, and 5-hydroxytryptamine receptors. The second one is the 'Pore-loop' channels that include the...
Direct-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
The direct-acting...
Cholinergic Antagonists: Chemistry and Structure-Activity Relationship
G-Protein Gated Ion Channels
Sensory organs,...
