The role of central 5-HT(2C) and NMDA receptors on LPS-induced feeding behavior in chickens.
In mammals, LPS regulate feeding primarily through the 5-HT(1A) and 5-HT(2c) receptors within the brain. However, the central effect of 5-HT(1A) and 5-HT(2c) on LPS-induced feeding behavior has not been studied in non-mammalian species. Also, the role of glutamatergic system in LPS-induced anorexia has never been examined in either mammalian or non-mammalian species. Therefore, in this study, we examined the role of serotonergic and glutamatergic systems on LPS-induced anorexia in chickens. Food intake was measured in chickens after centrally administered lipopolysaccharide (LPS) (20 ng) (0 h), followed by intracerebroventricular (ICV) injection of the 5-HT(1A) autoreceptor agonist (8-OH-DPAT, 61 nmol), 5-HT(2c) receptor antagonist (SB 242084, 30 nm), and NMDA receptor antagonist (DL-AP5, 5 nm) at the onset of anorexia (4 h). In the following experiments, we used DL-AP5 before 5-HT (10 μg) and SB242084 before glutamate (300 nm) for evaluation of the interaction between 5-HTergic and glutamatergic systems on food intake. The results of this study showed that SB 242084 and DL-AP5 significantly attenuated food intake reduction caused by LPS (P < 0.05) but 8-OH-DPAT had no effect. In addition, 5-HT-induced anorexia was significantly attenuated by DL-AP5 pretreatment (P < 0.05), while SB 242084 had no effect on glutamate-induced hypophagia. These results indicated that 5-HT and glutamate (via 5-HT(2c) and NMDA receptor, respectively) dependently regulate LPS-induced hypophagia in chickens.
Department of Physiology, Faculty of Veterinary Medicine, University of Tehran, 14155-6453, Tehran, Iran. zendedel@ut.ac.ir
Morteza
M
Zendehdel
Majid
M
Taati
Hosein
H
Jonaidi
Elham
E
Amini
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D000855:Anorexia / Q000139:chemically induced; D002645:Chickens; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D044405:Receptor, Serotonin, 5-HT2C / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology*; D058825:Serotonin 5-HT1 Receptor Agonists / Q000494:pharmacology; D058830:Serotonin 5-HT2 Receptor Antagonists / Q000494:pharmacology
C107820:6-chloro-5-methyl-1-((2-(2-methylpyrid-3-yloxy)pyrid-5-yl)carbamoyl)indoline; D000631:Aminopyridines; D007211:Indoles; D008070:Lipopolysaccharides; D044405:Receptor, Serotonin, 5-HT2C; D016194:Receptors, N-Methyl-D-Aspartate; D058825:Serotonin 5-HT1 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists; D015763:2-Amino-5-phosphonovalerate; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin