Vasoactive intestinal peptide-containing neurons in the paraventricular nucleus may participate in regulating...

Vasoactive intestinal polypeptide (VIP) immunoreactivity is present in varicosities and fibers in the hypothalamic paraventricular nucleus (PVN) in normal control animals. Adrenalectomy and lactation combined with colchicine treatment results in the appearance of a large population of VIP-immunopositive cell bodies in the parvocellular part of the PVN. Adrenalectomy, as well as lactation, significantly increases the number of VIP-positive fibers in the external zone of the median eminence. These observations suggest that the VIP-immunopositive neurons in the PVN may participate in regulating prolactin and corticotropin secretion.