The effect of serotonergic system on nociceptin/orphanin FQ induced food intake in chicken

• Published in: The journal of physiological sciences Vol. 63; no. 4; pp. 271 - 277
• Main Authors: Zendehdel, Morteza, Mokhtarpouriani, Kasra, Babapour, Vahab, Baghbanzadeh, Ali, Pourrahimi, Maryam, Hassanpour, Shahin
• Format: Journal Article
• Language: English
• Published: Japan Springer Japan 01-07-2013
• Subjects: 8-Hydroxy-2-(di-n-propylamino)tetralin - pharmacology; Aminopyridines - pharmacology; Animals; Chickens; Feeding Behavior - drug effects; Fenclonine - pharmacology; Fluoxetine - pharmacology; Indoles - pharmacology; Injections, Intraventricular; Male; Nociceptin; Opioid Peptides - administration & dosage; Opioid Peptides - pharmacology; Original Paper; Receptor, Serotonin, 5-HT2C - physiology; Serotonin - physiology; Serotonin 5-HT2 Receptor Antagonists - pharmacology; Serotonin Antagonists - pharmacology
• ISSN: 1880-6546; 1880-6562
• DOI: 10.1007/s12576-013-0263-x

The present study was designed to examine the effects of intracerebroventricular injection of para-chlorophenylalanine (PCPA) (cerebral serotonin depletive), fluoxetine (selective serotonin reuptake inhibitor), 8-OH-DPAT (5-HT1A autoreceptor agonist) and SB 242084 (5-HT2c receptor antagonist) on nociceptin/orphanin FQ (N/OFQ) induced feeding response in chickens. A guide cannula was surgically implanted into the lateral ventricle of chickens. Before the experiments, 3-h fasting periods had been given to all experimental birds. In experiment 1, chickens were injected with PCPA (1.5 μg) followed by an N/OFQ injection (16 nmol) intracerebroventricularly. In experiment 2, birds received fluoxetine (10 μg) prior to the injection of N/OFQ. In experiment 3, chickens were administered with N/OFQ after the 8-OH-DPAT administration (15.25 nmol). In experiment 4, birds were injected with SB 242084 (1.5 μg) followed by an N/OFQ injection. Cumulative food intake was measured at 3 h post injection. The results of this study show that N/OFQ increases food intake in broiler cockerels (P < 0.05) and that this effect is amplified by pretreatment with PCPA and SB 242084 in an additive manner (P < 0.05). The effect of N/OFQ is not changed by pretreatment with 8-OH-DPAT (P > 0.05). Furthermore, the stimulatory effect of N/OFQ on food intake was significantly attenuated by pretreatment with fluoxetine. These results suggest that N/OFQ induced hyperphagia is mediated by serotonergic mechanisms, and possibly imply an interaction between N/OFQ and the serotonergic system (via 5-HT2C receptors) on food intake in chickens.