Behavioral Effects in Adulthood of Serotonin Depletion by P-Chlorophenylalanine Given Neonatally to Male Rats

Abstract

The effect in malt rats of depletion of brain 5HT over days 1–7 or 8–16 after birth, by daily administration of 100 mg/kg PCPA was noted on various behaviors after the animals had reached adulthood. Treatment over days 1–7 had little or no effect, but over days 8–16 induced the following behavioral changes: In the elevated plus-maze. the treated group spent longer on the open arms, indicating a lower level of anxiety. In a test for sexual orientation, the treated animals were more sexually oriented toward the female stimulus and they showed a reduction in pendulum movements (a fear-related parameter); however their sexual performance with a receptive female was not different from the controls. The animals were also tested as residents in a resident-intruder paradigm for their social and agonistic activity. The treatment induced an increase in offensive activity confined to the high intensity elements and a parallel decrease in defensive activity. These results can be interpreted in terms of an increased reactivity to environmental and social cues and a decreased anxiety.

Key Words:

• 5HT
• PCM
• neonate
• anxiety
• sexual behavior
• aggression