Yokukansan-induced reduction of ethanol preference is associated with antagonism of 5-HT3 receptors

Abstract Background We recently reported that alkaloids in Uncaria hook (a constituent of yokukansan) contribute to antagonism of 5-HT 3 receptors. Many studies have reported that 5-HT 3 receptor antagonists reduce alcohol preference. However, the effect of yokukansan on alcohol preference is not clear. Purpose This study was performed to investigate the direct effect of yokukansan on alcohol preference and the effect of 5-HT 3 receptors on the preference. Study design We examined ethanol preference effected by yokukansan. Next, we analyzed the contribution of 5-HT 3 receptors to the effect of yokukansan. Methods Ethanol preference was measured using the two-bottle preference test in mice fed with or without yokukansan diet. Next, the contribution of 5-HT 3 receptors to ethanol preference was investigated using 5-HT 3 receptor-deficient mice. Results Reduction of ethanol preference by yokukansan was not observed using 5-HT 3 receptor deficient mice. Conclusion Yokukansan contributes to reduced ethanol preference and antagonism of 5-HT 3 receptors is associated with the effect.