Neuropeptide Y in the arcuato-paraventricular pathway and diet selection in the vasopressin-deficient Brattleboro rat.

Neuropeptide Y (NPY) is one of the most important brain peptides involved in feeding behavior. It influences both food choice and fluid homeostasis. The paraventricular and arcuate nuclei belong to the main pathway through which NPY stimulates carbohydrate intake. In this study, we measured NPY in various hypothalamic microdissected areas in Brattleboro di/di rats, a rat model of diabetes insipidus with specific dietary preferences. We confirmed that this rat is characterized by an increased fat intake (+10%; p<0.001) and a decreased carbohydrate intake (-10%; p<0.001) leading to a completely different dietary profile than that of di/+ controls. This profile was associated with a decrease in NPY in the paraventricular nucleus (-33%; p<0.005) and in the ventromedial nucleus (-24%; p<0.002). Intake of carbohydrate was negatively correlated with the gradient of NPY concentration between the arcuate and paraventricular nuclei. NPY could therefore contribute to the qualitative changes of feeding behavior in the Brattleboro rat through altered transport/release of the peptide and participate in the balance of neuropeptides that determines food choice in this strain of rat.