Neuropeptide Y-like immunoreactivity is present in boutons synapsing on vasopressin-containing neurons in rabbit supraoptic nucleus.

Ultrastructural immunocytochemical methods were used to examine the relationship between nerve terminals containing neuropeptide Y-like immunoreactivity and vasopressin-containing neurons in the rabbit supraoptic nucleus. Some boutons containing neuropeptide Y-like immunoreactivity formed synapses on the soma and proximal dendrites of vasopressin-containing neurons.