Nakamura Y, Ishida Y, Kondo M, Shimada S. Yokukansan contains compounds that antagonize the 5-HT
3 receptor.
PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2018;
43:120-125. [PMID:
29747744 DOI:
10.1016/j.phymed.2018.04.034]
[Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 02/23/2018] [Accepted: 04/15/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND
We recently focused on alkaloids in Uncaria hook (a constituent of the Kampo medicine, yokukansan) and identified the pharmacological action of geissoschizine methyl ether on several G protein-coupled receptors. However, the functions of other identified alkaloids in Uncaria hook, including hirsutine, hirsuteine, rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine, are not clear.
PURPOSE
To evaluate the effect of seven alkaloids in Uncaria hook (hirsutine, hirsuteine, rhynchophylline, isorhynchophylline, corynoxeine, isocorynoxeine and geissoschizine methyl ether) on the hydroxytryptamine type-3 (5-HT3) receptor ion channel.
STUDY DESIGN
We examined the effect of these alkaloids on the current of human 5-HT3 receptors expressed in Xenopus laevis oocytes.
METHODS
The human 5-HT3A subunit alone for the 5-HT3A receptor, or 5-HT3A and 5-HT3B subunits for the 5-HT3AB receptor, were expressed in Xenopus laevis oocytes. The 5-HT current was measured with or without alkaloid application using a two-electrode voltage clamp.
RESULTS
Each alkaloid, except for geissoschizine methyl ether, weakly inhibited the 5-HT-mediated 5-HT3A and/or 5-HT3AB receptor current, but co-application of these seven alkaloids inhibited the current strongly.
CONCLUSION
Each alkaloid contributes to antagonism of the 5-HT3 receptor.
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