3-Hydroxy agomelatine is a metabolite of Agomelatine. 3-Hydroxy agomelatine is a 5-HT2C receptor antagonist with an IC50 of 3.2 μM and a Ki of 1.8 μM[1].
Agomelatine and S 21517 have moderately high affinities for 5-HT2C receptors (Ki = 0.21 μM and 0.13 μM, respectively). The metabolite 3-Hydroxy agomelatine (S 21540) has a 10-fold lower affinity (Ki = 1.8 μM). Agomelatine, S 21517 and 3-Hydroxy agomelatine (10-7-10-4 M) are antagonists at 5-HT2C receptors, with a rank order of efficacy as follows: S 21517>Agomelatine>3-Hydroxy agomelatine[1].
Increasing doses (from 1.25 to 40 mg/kg, intraperitoneal injection) of 3-Hydroxy agomelatine (S 21540) does not affect the penile erections induced by mCPP and Ro 60-0175 in Wistar rat[1].
[1]. Chagraoui A, et al. Agomelatine(S 20098) antagonizes the penile erections induced by the stimulation of 5-HT2C receptors in Wistar rats. Psychopharmacology (Berl). 2003 Oct;170(1):17-22.