The role of dopamine in the control of neuropeptide Y neurons in the rat arcuate nucleus.

In order to determine the role of dopamine (DA) on neuropeptide Y (NPY) neurons in the arcuate nucleus of the rat hypothalamus, we evaluated the effects of alpha-methylparatyrosine (alpha-MPT), an inhibitor of catecholamines biosynthesis, and haloperidol, a dopaminergic antagonist, on NPY immunoreactive neurons. The two drugs used produced in the arcuate nucleus the appearance of a large number of NPY-containing neuronal bodies which are normally absent in control animals. The density of stained fibers were not significantly modified. These results suggest that DA can exert some negative regulation of NPY neurons activity in the arcuate nucleus.