CRF1/CRF2 and MC3/MC4 Receptors Affect Glutamate- Induced Food Intake in Neonatal Meat-Type Chicken

Abstract

Central glutamate, melanocortin and corticotropin systems have mediatory role on several physiologic functions in the brain, but their interactions on appetite regulation are not fully elicited. So, the aim of the current study was to determine interaction of the glutamate with melanocortin and corticotropin systems on food intake in 3-h food-deprived (FD 3 ) neonatal meat-type chicken. In experiment 1, chicken intracerebroventricular (ICV) injected (A) phosphate-buffered saline (PBS), (B) glutamate (75 nmol), (C) glutamate (150 nmol) and (D) glutamate (300 nmol). In experiment 2, (A) PBS, (B) astressin-B (CRF 1 /CRF 2 receptors antagonist, 30 µg), (C) glutamate (300 nmol) and (D) astressin-B+glutamate were ICV injected. Experiments 3-5 were similar to experiment 2, except birds were injected with astressin2-B (CRF 2 receptor antagonist, 30 µg), SHU9119 (MC 3 /MC 4 receptor antagonist, 0.5 nmol) and MCL0020 (MC 4 receptor antagonist, 0.5 nmol) instead of the astressin-B. In experiment 6, the injections were (A) PBS, (B) MTII (MC 3 /MC 4 receptor agonist, 2.5ng), (C) glutamate (75nmol) and (D) MTII+glutamate. Then, cumulative feed intake was recorded at 30, 60 and 120 minutes after injection. According to the results, dose dependent hypophagia observed by ICV injection of the glutamate (75, 150 and 300nmol) compared to control group in neonatal broiler chicken (p<0.05). Co-injection of the astressin-B+glutamate and astressin2-B+glutamate decreased glutamateinduced hypophagia in neonatal broiler chicken (p<0.05). Coinjection of the glutamate+MC 3 /MC 4 receptors antagonist decreased hypophagic effect of the glutamate (p<0.05). These results suggested hypophagic effect of the glutamate mediates via CRF 1 /CRF 2 and MC 3 / MC 4 receptors in chickens.

The Crosstalk Between Brain Mediators Regulating Food Intake Behavior in Birds: A Review

“…As reported, receptor antagonist of MCR S and CRF S adjust the effect of glutamate on feed desire in a manner that the administration of the receptors MC 3,4 antagonists, similar to that of in CRF 1,2 receptors, attenuated the hypophagic effect of glutamate. These results suggested that the hypophagic effect of glutamate mediates via CRF 1,2 and MC 3,4 receptors in chickens (Ahmadi et al 2019). Moreover, it has been shown that the effect of glutamate on feeding behavior is enhanced through the GABA A receptor antagonist (Zendehdel et al 2009).…”

“…As a result of these interactions, anorexigenic effect of LPS, ghrelin, RFRP-3, and glutamate is attenuated by central injection of CRF receptors antagonist. Moreover, as mentioned earlier, there is an interplay between 5-HT (5-HT2c) and CRF (Kooshki et al 2019;Saito et al 2005;Moosadoost et al 2020;Ahmadi et al 2019).…”

“…It is further reported that the 5-HT anorexigenic effect is mediated by receptors of melanocortin (Zendehdel et al 2012a). Moreover, the hypophagic effect of glutamate is decreased through MC 3,4 receptors antagonist (Ahmadi et al 2019;Shiraishi et al 2008). Besides, it has been depicted that, central injection of insulin in chicks significantly increased expression of POMC mRNA which leads to diminish food intake (Shiraishi et al 2008).…”

The Effect of the Central Administration of the Neuropeptide VF on Feed Intake and Its Possible Interactions with Glutamate and Opioid Systems in Broiler Chicken

“…Excitatory amino acid neurotransmitter glutamate exists in the CNS, and according to our understanding, two types of its receptors (ionotropic and metabotropic receptors) have been identi ed. N-Methyl-Daspartate receptor (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and Kainate receptors which are ionotropic, while metabotropic receptors are mGLUR 1 , mGLUR 2, as well as mGLUR 3 (Ahmadi et al 2019). According to the previous study (Hettes et al 2010) (Mortezaei et al 2013), chickeating behaviors improved and were limited after ICV delivery of NMDA receptor antagonist and AMPA receptors agonist, respectively.…”