Undernutrition during early life alters neuropeptide Y distribution along the arcuate/paraventricular pathway

Perinatal nutrient restriction exerts profound influences on brain development. Animals that suffer undernutrition during lactation also display impaired weight gain. Feeding behavior is mainly modulated by neural and hormonal inputs to the hypothalamus. The arcuate-paraventricular neuropeptidergic Y pathway has a prominent role in appetite regulation. The aim of this work was to study the effects of protein undernutrition during lactation on this hypothalamic pathway. We used rats from 5 to 60 postnatal (P) days whose dams were fed a 0% protein diet (PFG) or a normoprotein diet (CG) from P1 to P10. To reproduce the same amount of calorie ingested by the PFG we used an underfed group (UFG). Immunohistochemistry was performed to assess neuropeptide Y (NPY) distribution in the arcuate, periventricular and paraventricular nuclei. Our results showed a NPY immunostaining peak at P10 in all nuclei in CG animals. In UFG animals this peak was observed by P15, while, in the PFG animals only by P20. Our results suggest that the neuropeptidergic arcuate-paraventricular pathway suffered a delay in NPY distribution in undernourished animals, particularly those fed a 0% protein diet, reflecting an effect on this pathway maturation that could explain previously reported alterations on feeding behavior in these animals.