The Interaction of Dopaminergic System and GABAB Receptor in Feed Intake Regulation of Neonatal Chicken

Animal studies have shown the role of gamma amino butyric acid (GABAergic) and Dopaminergic systems in controlling appetite, but their interactions in birds have not yet been investigated . In this study, 6 experiments were carried out to investigate the interactions between GABArergic and dopaminergic systems in fresh laying hens (Each experiment included 4 groups, 11 chicks per group). Chicks received intracerebroventricular (ICV) injections after 3h of starvation in the following form: In 6 experiments; Each experiment has 4 groups. Group 1 (CON): Received Saline as a control group. Group 2 (DOP): Dopamine neurotransmitters include 125 nmol L-DOPA (levo-dihydroxyphenylalanine) as a dopamine precursor. 6-OHDA, 2.5 nmol as a dopaminergic neurotoxin. SCH23390, 5nmol. AMI-193, 5nmol. NGB2904, 6.4nmol and L-741742, 6nmol. (L-DOPA, 6-OHDA, D1 receptor, D2 receptor, D3 receptor and D4 receptor antagonists), respectively (each of them in one of the experiments). Group 3 (GABA): Baclofen, 0.2μm (GABAB agonist). Group 4 (DOP+GABA): Receive Baclofen simultaneously with any of the L-DOPA, 6-OHDA, D1, D2, D3 and D4 antagonists, respectively (each of them in one experiments). Cumulative consumption of feed (based on the percentage of body weight) was measured up to 120 minutes after the injection. According to the results, ICV injection of Baclofen alone significantly increased feed intake (P < 0.05). None of the dopamine receptors (L-DOPA, 6-OHDA, D1, D2, D3, D4, as well as dopamine synthesis inhibitors) did not affect feed intake (P > 0.05). The co-injection of the L-DOPA, 6-OHDA, D1-D4 receptor antagonists + baclofen (P> 0.05) showed no significant effect. The results of this study showed that dopaminergic and GABAB receptors had no interaction in FD3 neonatal layer-type chicken.