Intracerebroventricular administration of GABA-A and GABA-B receptor antagonists attenuate feeding and sleeping-like behavior induced by L-pipecolic acid in neonatal chicks.
It has been demonstrated that L-pipecolic acid (L-PA), a major metabolic intermediate of L-lysine (L-Lys) in the mammalian and chicken brain, is involved in the functioning of the GABAergic system. A previous study has shown that intracerebroventricular (i.c.v.) injection of L-PA suppressed feeding and induced sleep-like behavior in neonatal chicks; however, the precise relationship between the GABAergic system and L-PA has not been clarified. In the present study, the role of the GABA-A or GABA-B receptors in the suppression of food intake and induction of sleeping-like behavior by L-PA was investigated. Chicks were injected i.c.v. with the GABA-A antagonist picrotoxin or GABA-B antagonist CGP54626 along with L-PA. Although suppression of food intake by L-PA was restored partially by co-injection with CGP54626, but not picrotoxin, sleep-like behavior induced by L-PA was suppressed significantly by both antagonists. These results suggested that L-PA activated both GABA-A and GABA-B receptors, and GABA-B receptors alone contributed to food intake whereas both receptors contributed to sleep-like behavior.
Takagi
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T
Laboratory of Advanced Animal and Marine Bioresources, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan.
Bungo
T
T
Tachibana
T
T
Saito
E-S
ES
Saito
S
S
Yamasaki
I
I
Tomonaga
S
S
Denbow
D M
DM
Furuse
M
M
D000818:Animals; D000831:Animals, Newborn; D002645:Chickens; D004435:Eating / Q000187:drug effects / Q000502:physiology; D005247:Feeding Behavior / Q000187:drug effects* / Q000502:physiology; D018756:GABA Antagonists / Q000008:administration & dosage; D058787:GABA-A Receptor Antagonists; D058788:GABA-B Receptor Antagonists; D007276:Injections, Intraventricular; D008297:Male; D010875:Pipecolic Acids / Q000494:pharmacology*; D011963:Receptors, GABA-A / Q000502:physiology; D018080:Receptors, GABA-B / Q000502:physiology; D012890:Sleep / Q000187:drug effects* / Q000502:physiology
D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D058788:GABA-B Receptor Antagonists; D010875:Pipecolic Acids; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; C031345:pipecolic acid