Increase of neuropeptide Y-like immunoreactivity in the paraventricular nucleus of fasting rats.

The paraventricular nucleus (PVH) of the hypothalamus is a key region for the control of food intake. It presents a very high neuropeptide Y (NPY)-like positive innervation. In this paper we have studied the modifications of NPY-positive innervation in the PVH of 72 h starved rats vs control rats by means of semiquantitative immunocytochemistry. We observed a significant increase of NPY-like immunoreactivity in fasting rats. This result suggests a physiological role of NPY in the food intake regulation at the PVH level.