Intracerebroventricular injection of pipecolic acid inhibits food intake and induces sleeping-like behaviors in the neonatal chick

It has been demonstrated that l -pipecolic acid ( l -PA), a major metabolic intermediate of l -Lysine ( l -Lys) in the brain, is involved in the functioning of Γ-aminobutyric acid. In the present work the effect of intracerebroventricular (i.c.v.) administration of l -PA, and its relatives, on food intake and behavior in neonatal chicks was investigated. The i.c.v. injection of 1 mg of l -PA and d -PA significantly inhibited food intake during the 2 h following injection, whereas greater than 2 mg of l -Lys was required to inhibit food intake. In behavioral tests, the i.c.v. injection of l -PA reduced active wakefulness and feeding behavior while inducing sleeping-like behavior in chicks. These results suggest that l -PA has an important role for the regulation of behaviors in the neonatal chick after conversion from l -Lys in the brain.