Relenopride (YKP10811) hydrochloride is a specific and selective 5-HT4 receptor agonist (Ki=4.96 nM). Relenopride hydrochloride has 120-fold and 6-fold lower affinity, respectively, for 5-HT2A (Ki=600 nM) and 5-HT2B receptors (Ki=31 nM) than for 5-HT4. Relenopride hydrochloride increases gastrointestinal (GI) motility[1][2].
Relenopride hydrochloride do not show any significant off-target binding to any other receptors, enzymes, orserotonin-receptor subtypes at 1 μM, except for binding to the 5-HT2A receptor and the 5-HT2B receptor. Relenopride hydrochloride shows antagonist activity at the 5-HT2B receptor with an IC50 of 2.1 μM and no significant activity at the 5-HT2A receptor up to 10 μM. Relenopride hydrochloride shows no activity against serotonin-receptor subtypes 5-HT1B, 5-HT1D, or 5-HT2A at 1 nM to 10 μM, or for serotonin-receptor subtype 5-HT7 at 10 nM to 30 μM[1].
[1]. Shin A, et al. A randomized trial of 5-hydroxytryptamine4-receptor agonist, YKP10811, on colonic transit and bowel function in functional constipation. Clin Gastroenterol Hepatol. 2015;13(4):701-8.e1.
[2]. Yin J, et al. Prokinetic effects of a new 5-HT4 agonist, YKP10811, on gastric motility in dogs. J Gastroenterol Hepatol. 2017;32(3):625-630.
[3]. Gilet M, et al. Influence of a new 5-HT4 receptor partial agonist, YKP10811, on visceral hypersensitivity in rats triggered by stress and inflammation. Neurogastroenterol Motil. 2014;26(12):1761-1770.