Effect of intracerebroventricular (ICV) injection of adrenomedullin and its interaction with NPY and CCK pathways on food intake regulation in neonatal layer-type chicks

Background: Adrenomedullin has various physiological roles including appetite regulation. The objective of present study was to determine the effects of intracerebroventricular injection of adrenomedullin and its interaction with NPY and CCK receptors on food intake regulation in layer-type chicks. In experiment 1, chickens received ICV injection of saline and adrenomedullin (1, 2 and 3 nmol). In experiment 2, birds injected with saline, B5063 (NPY 1 receptor antagonist, 1.25 µg), adrenomedullin (3 nmol) and co-injection of B5063 + adrenomedullin. Experiments 3–5 were similar to experiment 2 and only SF22 (NPY 2 receptor antagonist, 1.25 µg), SML0891 (NPY 5 receptor antagonist, 1.25 µg) and CCK 4 (1 nmol) were injected instead of B5063. In experiment 6, ICV injection of saline and CCK 8s (0.125, 0.25 and 0.5 nmol) were done. In experiment 7, chickens injected with saline, CCK 8s (0.125 nmol), adrenomedullin (3 nmol) and co-injection of CCK 8s  + adrenomedullin. After the ICV injection, birds were returned to their individual cages immediately and cumulative food intake was measured at 30, 60 and 120 min after injection. Results According to the results, adrenomedullin (2 and 3 nmol) decreased food intake compared to control group (P < 0.05). Co-injection of the adrenomedullin + B5063 amplified hypophagic effect of adrenomedullin (P < 0.05). The ICV injection of the CCK 8s (0.25 and 0.5 nmol) reduced food intake (P < 0.05). Co-injection of the CCK 8s  + adrenomedullin significantly potentiated adrenomedullin-induced hypophagia (P  0.05). Conclusion These results suggested that the hypophagic effect of the adrenomedullin is mediated by NPY 1 and CCK 8s receptors. However, our novel results should form the basis for future experiments.