RESUMEN
The effect of the malnutrition during suckling on the aggressiveness was investigated in adult rats treated or not with citalopram, a selective serotonin reuptake inhibitor (SSRI). The animals were divided into two groups according to the diet used: nourished groupó the rats received the control diet with 23 per cent protein during the life; and malnourished groupó the rats had its mothers submitted to diet with 7.8 per cent protein during suckling. At 120 days of age, each group was sub-divided according to the treatment: acute ó consisting a single i.p. injection of saline solution or 20-mg/Kg citalopram; chronic ó consisting the single injections (1 per day during 14 days) of saline or 20 mg/Kg citalopram. The acute or chronic treatment with SSRI reduces aggressive response in nourished rats, but not in malnourished ones. Thus, the malnutrition during the critical period of brain development seems to induce durable alterations in the function of the serotoninergic neurotransmission