Interaction of Central Glutamatergic and Histaminergic Systems on Food Intake Regulation in Layer Chickens

This study purposed to discover the connection between the central glutamatergic and histaminergic systems on feeding behavior in layer chickens. In the first experiment, chicks obtained intracerebroventricular (ICV) injections of saline (control solution), α-FMH (۲۵۰ nmol), glutamate (۳۰۰ nmol), and α-FMH + glutamate. Experiments ۲-۶ were comparable to the first experiment, apart from the birds being injected with chlorpheniramine (histamine H۱ receptor antagonist, ۳۰۰ nmol), famotidine (histamine H۲ receptor antagonist, ۸۲ nmol), and thioperamide (histamine H۳ receptor antagonist, ۳۰۰ nmol) instead of α-FMH. In Experiment five, experimental groups were divided into (A) control solution, (B) MK-۸۰۱ (N-methyl-D-aspartate receptor antagonist, ۱۵ nmol), (C) histamine (۳۰۰ nmol) and (D) MK-۸۰۱ + histamine. Experiments ۶-۱۰ and Experiment five were similar apart from the ICV injections of CNQX (AMPA receptor antagonist, ۳۶۰ nm), UBP-۳۰۲ (Kainate receptor antagonist, ۳۹۰ nm), AIDA (mGluR۱ antagonist, ۲ nmol), LY۳۴۱۴۹۵ (mGluR۲ antagonist, ۱۵۰ nmol), and UBP۱۱۱۲ (mGluR۳ antagonist, ۲ nmol) given instead of MK-۸۰۱. Afterward, cumulative food intake was recorded at۳۰, ۶۰, and ۱۲۰ minutes after the injection process. According to the results, ICV injection of glutamate considerably reduced food intake (p<۰.۰۵). Co-injection of α-FMH + glutamate and/or chlorpheniramine + glutamate reduced the hypophagic influence of glutamate (p<۰.۰۵), whereas thioperamide + glutamate augmented glutamate-induced hypophagia in neonatal chicks (p<۰.۰۵). Co-injection of MK-۸۰۱ + histamine or UBP-۳۰۲ + histamine reduced the hypophagic influence of the histamine (p<۰.۰۵), whereas LY۳۴۱۴۹۵ + histamine augmented the hypophagic influence of the histamine (p<۰.۰۵). Given the results, it is suggested that the effect of the connection between these systems on the process of food intake regulation is mediated by H۱ and H۳ histamines as well as NMDA, Kainate, and mGluR۲ glutamate receptors in neonatal layer chickens.

کلیدواژه ها:

Central glutamate ، Histamine ، Food intake ، Layer chicken