Neonatal exposure to citalopram, a serotonin selective reuptake inhibitor, programs a delay in the reflex ontogeny in rats.

Serotonin influences the growth and development of the nervous system, as well as its behavioral manifestations. The possibility exists that increased brain serotonin availability in young animals modulates their neuro-behavioral responses. This study investigated the body weight gain and reflex ontogeny of neonatal rats treated during the suckling period with two doses of citalopram (5 mg, or 10 mg/kg, s.c., daily). The time of the appearance of reflexes (palm grasp righting, free-fall righting, vibrissa placing, auditory startle response, negative geotaxis and cliff avoidance) as well as the body weight evolution were recorded. In general, a delay in the time of reflex development and a reduced weight gain were observed in drug-treated animals. These findings suggest that serotoninergic mechanisms play a role in modulating body weight gain and the maturation of most reflex responses during the perinatal period in rats.