Overview
- Tompson, A.J. et al. (2011) Neuropharmacology 60, 488.
Alomone Labs Ginkgolide B blocks 5-HT3A receptors expressed in HEK 293T cells.5-HT3A receptor currents were elicited by 10 µM 5-HT, delivered every 3 minutes. Ginkgolide B (#G-170) was applied 30 seconds before stimulation at 50, 200 and 500 µM, as indicated and inhibited the 5-HT induced current in a dose dependent and reversible manner.
Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter synthesized from the amino acid tryptophan by the enzyme tryptophan-decarboxylase. 5-HT3 channel is a ligand gated ion channel receptor of the cys-loop channel family. It is a pentamer with five subunits surrounding a central channel1.
Ginkgolide B is a natural non-selective blocker of 5-HT3A channel. Ginkgolide is extracted from the leaves, roots and bark of the tree Ginkgo biloba. Ginkgolide B has an effective concentration of 500-1000 μM and an IC50 of 730 μM for the 5-HT3A receptor and an IC50 of 3.9 mM for the 5-HT3B receptor thus enabling discrimination between the two. Ginkgolide also binds to anion Cys-loop receptors such as GABA and glycine receptors. Ginkgolide does not displace the specific 5-HT3 receptor antagonist granisetron, thus confirming that it does not act at the agonist binding site. In addition, inhibition by Ginkgolide at 5-HT3A receptors is weakly use-dependent, and recovery of the receptor is also activity dependent, indicating channel block as the mechanism of inhibition. Ginkgolide is widely used in traditional medicine and has a wide spectrum of beneficial properties such as anti-convulsion, neuro-protection and reducing anxiety2.
