Effects of triterpenoid Alisol-F on human 5-hydroxytryptamine 3A and α3β4 nicotinic acetylcholine receptor channel activity

Abstract

Alisma Rhizome is a known tradition medication, which has been used for its diuretic, hypolipidemic, anti-diabetic, and anti-inflammatory purposes for thousands of years. The primary compounds of Alisma Rhizome are protostane type triterpenes, such as Alisols A, B or C. We previously demonstrated that Alisol derivatives (Alisols A, B, and C) have inhibitory effects on 5-hydroxytryptamine 3A (5-HT3A) currents1. In this study, we tested the effects of a new triterpene, Alisol-F, on human 5-HT3A and α3β4 nicotinic acetylcholine (nACh) receptor channel currents by using Xenopus oocytes expressing these channels. Co-application of Alisol-F inhibited 5-HT3A and α3β4 nACh receptor-mediated inward peak currents. The inhibitory effect of Alisol-F on 5-HT and ACh-induced inward peak currents occurred in a reversible and concentration- dependent manner. The half maximal inhibitory concentrations (IC50) of Alisol-F were 79.4 ± 11.0 and 21.2 ±6.0 μM for the 5-HT3A and α3β4 nACh receptors, respectively. In addition, the inhibition of I 5-HT and I ACh by Alisol-F occurred noncompetitive and voltage insensitive manner. Taken together, these results show that Alisol-F may regulate 5-HT3A and α3β4 nACh receptors channel expressed in Xenopus oocytes.