Citalopram reduces social interaction in rats by activation of serotonin (5-HT)(2C) receptors.

The selective serotonin (5-HT) reuptake inhibitor (SSRI), citalopram (2.5 mg/kg, s.c.), reduced social interaction (SI) in rats. This action was abolished by the 5-HT(2B/2C) receptor antagonist, SB206, 553 (0.63 mg/kg, s.c.), and the 5-HT(2C) receptor antagonist, SB242, 084 (0.04 mg/kg, i.p.), but not by the 5-HT(2A) antagonist, MDL100, 907 (0.04 mg/kg, s.c.), the 5-HT(1A) antagonist, WAY100,635 (0.16 mg/kg, s.c.), or the 5-HT(3) antagonist, ondansetron (0.16 mg/kg, s. c.). These data suggest that 5-HT(2C) receptors are involved in the "anxiogenic" actions of citalopram.