Role of cannabinoidergic system on food intake in neonatal layer-type chicken

Abstract

Central regulatory mechanisms for neurotransmitters of food intake vary among animals. Endocannabinoids have crucial role on central food intake regulation in mammals but its role has not been studied in layer-type chicken. Thus, in this study 6 experiments designed to evaluate effects of intracerebroventricular (ICV) administration of 2-AG (2-Arachidonoylglycerol, selective CB1 receptors agonist), SR141716A (selective CB1 receptors antagonist), JWH015 (selective CB2 receptors agonist), AM630 (selective CB2 receptors antagonist) on feeding behavior in 3 h food deprived neonatal layer-type chickens. In experiment 1, birds ICV injected with control solution and 2-AG (0.25, 0.5 and 1 μg). In experiment 2: control solution, SR141716A (6.25, 12.5 and 25 μg) were ICV injected to birds. In experiment 3 animals received: control solution, SR141716A (6.25 μg), 2-AG (1 μg) and co-injection of SR141716A+2-AG. In experiment 4, chickens received control solution and JWH015 (6.25, 12.5 and 25 μg). In experiment 5, control solution and AM630 (1.25, 2.5 and 5 μg) were injected. In experiment 6, the birds received control solution, AM630 (1.25 μg), JWH015 (25 μg) and co-administration of AM630+JWH015. Then, cumulative food intake was recorded until 120 min after injection. According to the results, 2-AG dose dependently increased cumulative food intake while SR141716A reduced appetite compared to control group (P < 0.05). Injection of 2-AG (1 μg) amplified food intake and its effect minimized by SR141716A (6.25 μg) (P < 0.05). Also, ICV injection of JWH015 (25 μg) dose dependently increased food intake and co-injection of JWH015+AM630 decreased JWH015-induced food intake (P < 0.05). These results suggest CB1 and CB2 receptors have an important role on ingestive behavior in FD3 neonatal layer-type chicken.

Involvement of Gaba and Cannabinoid Receptors in Central Food Intake Regulation in Neonatal Layer Chicks: Role of CB1 and Gabaa Receptors

“…To the best of our knowledge, there are no studies describing the interaction between CBergic and GABAergic systems on food intake in FD 3 neonatal layer-type chickens. According to the results, ICV injection of CB 1 and CB 2 agonists amplified food consumption in layertype chicks which was similar to mammals (Chen et al, 2006;Wiley et al, 2012) and recent studies on layertype chicks (Alizadeh et al, 2015;Hassanpour et al, 2015). However, these results were dissimilar compared to broilers which only CB 2 receptors were responsible for feeding (Emadi et al, 2011;Novoseletsky et al, 2011).…”

“…Reports claim just CB 1 receptors have a regulatory role on appetite in broilers Novoseletsky et al, 2011). Recent reports revealed both CB 1 and CB 2 receptors have hyperphagic effect in neonatal layer-type chicken (Alizadeh et al, 2015;Hassanpour et al, 2015).…”

“…Comparative physiological studies suggested there are differences award pathways between the meat-type and layertype chicks (Alizadeh et al, 2015). For example, food intake mediates via both CB 1 and CB 2 receptors in layer-type chicken (Alizadeh et al, 2015) but only CB 2 receptors interact on feeding in meat-type chicken (Emadi et al, 2011;Novoseletsky et al, 2011). For instance, ICV injection of Baclofen had no effect on food intake in broilers (Jonaidi et al, 2002;Tajalli et al, 2006;Zendehdel et al, 2008Zendehdel et al, , 2009.…”

“…In each group, 12 birds received the injection, but just data of those individuals where the dye was present in their lateral ventricle (12 chickens per group), was used for the analysis. All experimental procedures were done from 8:00 A.M. until 3:30 P.M. Also, the time course for feeding behavior was selected by previous studies (Jonaidi et al, 2012;Zendehdel & Hassanpour 2014;Alimohammadi et al, 2015;Alizadeh et al, 2015;Hassanpour et al, 2015).…”

“…In other words, when an effective dose of a system was administered, the sub-effective dose of the other system was considered. These doses of drugs were determined according to the previous studies (Jonaidi et al, 2002;Chen et al, 2006;Emadi et al, 2011;Novoseletsky et al, 2011;Alizadeh et al, 2015;Hassanpour et al, 2015).…”