Agomelatine (S-20098) L(+)-Tartaric acid is a specific agonist of MT1 and MT2 receptors (Kis: 0.1, 0.06, 0.12, and 0.27 nM for CHO-hMT1, HEK-hMT1, CHO-hMT2, and HEK-hMT2). It also is a selective 5-HT2C receptor antagonist (pKis: 6.4 and 6.2 at native (porcine) and cloned (human) 5-HT2C receptors).

5-HT2C receptor (human):6.2 pki, 5-HT2C receptor (native porcine): pki： 6.4 , HEK-hMT1:0.06 nM (ki), MT2 (human, CHO cells):0.12 nM (ki), HEK-hMT2:0.27 nM (ki), MT1 (human, CHO cells):ki:0.1 nM

Agomelatine acts as a full agonist of MT1 and MT2 receptors with EC50s of 1.6, 0.10 nM for CHO hMT1 CHO-hMT2 (hΜΤ1 and hΜΤ2 receptors expressed in CHO or HEK cell membranes) [1]. Agomelatine also interacts with h5-HT2B receptors, whereas it shows low affinity at native (rat)/cloned, human 5-HT2A (<5.0/5.3), and 5-HT1A (<5.0/5.2) receptors, and negligible (<5.0) affinity for other 5-HT receptors [2].

Agomelatine (25, 50, or 75 mg/kg; i.p.) exhibits antioxidant activity in Strychnine (75 mg/kg, i.p.) or Pilocarpine (400 mg/kg, i.p.) induced seizure models in mice but does not affect oxidative stress parameters in Pentylenetetrazole (PTZ) or Picrotoxin (PTX) induced seizure models compared to controls [3].