Electron microscopic studies of medullary synaptic inputs to vasopressin-containing neurons in the hypothalamic paraventricular nucleus.
We have observed the ascending projections from the lower brain stem to the magnocellular vasopressin-like immunoreactive (VP-LI) neurosecretory neurons in the paraventricular nucleus (PVN) using electron microscopy. The tissues were prepared by a double labeling technique combining anterograde tracing after iontophoretic injection of wheat germ agglutinin-coupled horseradish peroxidase (WGA-HRP) in the A1 group (lateral reticular nucleus in the medulla oblongata) with VP immunocytochemistry. Both the WGA-HRP-labeled and the unlabeled axon terminals made synaptic contacts with VP-LI cell bodies and processes in the PVN. This indicates a direct synaptic influence of medullary A1 group on the secretory activity of the VP-containing neurons in the hypothalamic paraventricular nucleus.
Shioda
S
S
Department of Anatomy, Showa University School of Medicine, Tokyo, Japan.
Nakai
Y
Y
Iwase
M
M
Homma
I
I
D000818:Animals; D001369:Axons / Q000648:ultrastructure; D007150:Immunohistochemistry; D007478:Iontophoresis; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism / Q000648:ultrastructure*; D009434:Neural Pathways; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D010286:Paraventricular Hypothalamic Nucleus / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000378:metabolism / Q000648:ultrastructure*; D014667:Vasopressins / Q000378:metabolism*
D014667:Vasopressins