European Research Network, GDRE antidepressant action MT 1, MT 2 5-HT 2C A Novel Concept in the Treatment of Depression Agomelatine Melatonin agonist 5-HT 2C antagonist

European Research Network, GDRE Melatonergic and 5-HT 2C receptors are expressed in the suprachiasmatic nucleus, hippocampus and prefrontal cortex MT 1 and 5-HT 2C receptors are expressed in a circadian manner Potential synergy of melatonergic (MT 1, MT 2 ) and 5-HT 2C receptors: functional and neurochemical effects in depression models Boess and Martin, 1994; Moyer and Kennaway, 1999; Dubocovitch et al. 1996; Kennaway and Moyer, 1998; Varcoe et al. 2003; Barret et al minireview; Holmes et al. 1997; Masana et al. 2000; Dugovic and Wauquier, 1987; Dugovic et al. 1989; Papp et al Melatonergic and 5-HT 2C receptors: key players in circadian rhythm regulation and in depression Synaptic and intracellular signaling synergy?

European Research Network, GDRE Antidepressant activity of agomelatine: Combination of melatonin agonist and 5-HT2C antagonist effects 1 Bourin et al,2004; 2 Bertaina-Anglade et al. 2006; 3 Norman,2004; 4 Papp et al, 2003; 5 Barden et al. 2005; 6 Corbach et al 2008 ;, 7,8 data on file 2001 * Hight doses ( mg/kg); # less effective than agomelatine ## data on file 2006 All models are long-term administration (3 weeks) except forced-swim: agomelatine and melatonin ( mg/kg, i.p.). Typical antidepressant models Full spectrum of AD activity Circadian effect not sufficient 5-HT 2C antagonism not sufficient Agomelatine melatonin 5-HT 2C antagonists Stress or anxiety models Circadian models Learned Helplessness 2 Chronic mild stress 4 Bulbectomy 3 Isolated aggressive mice 7 Marble burying test 8 Despair test 1 Transgenic model (Gri mice) #+# - + ## ? /- * Psychosocial stress #+#

European Research Network, GDRE Effects of agomelatine on hippocampal cell survival in rats Agomelatine + S22153 (melatonin antagonist) Soumier et al, * BrdU+ cells (% control)«Dorsal» * BrdU + cells / region * BrdU+ cells ( % control) 5-HT2C inverse agonists vehicle Agomelatine «Ventral» * BrdU + cells / region SB243213SB melatonin S HT2C neutral antagonist Agomelatine *p<0.05 (two-way ANOVA). Potential synergy between melatonin agonist and 5HT2C antagonist properties Agomelatine + S 22153

European Research Network, GDRE Molecular dissection of the agomelatine acute effects on BDNF gene expression in the rat prefrontal cortex Acute agomelatine increased BDNF mRNA in the prefrontal cortex 16h after treatment. No effect was observed with melatonin or S32006 (a 5HT2C inverse agonist) The effects of agomelatine were blocked by a melatonin receptor antagonist (S22153) Possible synergy between melatonin agonist and 5HT2C antagonist properties on agomelatine’s effects on BDNF ***p<0.001 vs vehicle Calabrese et al. ECNP BDNF mRNA levels (% Vehicle) *** Vehicle Agomelatine (40 mg/kg) Melatonin (40 mg/kg) S32006 (10 mg/kg) *** BDNF mRNA levels (% Vehicle) Vehicle Agomelatine (40 mg/kg) Vehicle+ S22153 (20 mg/kg) S agomelatine (40 mg/kg)

European Research Network, GDRE Agomelatine: Improvement of Depressive States A HETEROGENEOUS AND COMPLEX PATHOLOGY Depressive States Improved by agomelatine Monoamine deficiency Emotional deficits Disrupted circadian rhythms Perturbed synaptic plasticity Under control of melatonin MT 1 /MT 2 and 5-HT 2C receptors