Journal of Neuroscience, Vol 8, 1940-1950, Copyright © 1988 by Society for Neuroscience
Origin of the atriopeptin-like immunoreactive innervation of the paraventricular nucleus of the hypothalamus
DG Standaert and CB Saper
Department of Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110.
The paraventricular nucleus of the hypothalamus (PVH) contains a prominent
collection of varicose atriopeptin-like immunoreactive (APir) fibers. We
have used immunohistochemistry and fluorescent retrograde tracers to
investigate the origin of these fibers. All parts of the PVH contain APir
fibers. The densest collections are found in the periventricular area and
in the parvocellular components of the nucleus. Somewhat smaller numbers of
fibers are found within the borders of the magnocellular part of the PVH.
Following the injection of fluorescent retrograde tracers into the PVH and
subsequent immunohistochemical staining, numerous retrogradely labeled APir
neurons were observed in the anteroventral periventricular nucleus (AVPV),
adjacent to the anteroventral tip of the third ventricle. Smaller groups of
retrogradely labeled APir neurons were observed in the ventromedial part of
the bed nucleus of the stria terminalis, the pedunculopontine and
laterodorsal tegmental nuclei, and the medial part of the nucleus of the
solitary tract. The APir projection from the AVPV to the PVH is of
particular interest in view of the abundant evidence implicating both
regions in the regulation of the fluid and electrolyte balance and blood
pressure. AP may serve as a central neuromodulator as well as a circulating
hormone in cardiovascular regulation.