Journal of Neuroscience, Vol 4, 1262-1270, Copyright © 1984 by Society for Neuroscience
In vivo biosynthesis and transport of oxytocin, vasopressin, and neurophysins to posterior pituitary and nucleus of the solitary tract
JD White, JE Krause and JF McKelvy
A growing body of literature suggests that oxytocin (OXY) and arginine-
vasopressin (AVP), in addition to their neuroendocrine roles, may serve as
neuromodulators within the central nervous system of mammals. The present
study investigated the biosynthesis of OXY, AVP, and their associated
neurophysins in the paraventricular nucleus of the hypothalamus (PVN) and
the transport of these peptides to the neural lobe and the nucleus of the
solitary tract (NTS) in the brainstem of the rat. Rats were cannulated
bilaterally in the PVN, and 24 hr later a 2-hr pulse of [35S]cysteine was
administered using an Alzet minipump delivery system. After a 10-hr chase
period, the neural lobe was removed and the PVN and NTS were punched.
Tissue homogenates were adsorbed to and eluted from octadecyl-silica
cartridges and analyzed by linear high performance liquid chromatography
(HPLC) gradient elution, chemical and enzymatic modification, and
exponential gradient HPLC elution followed by linear HPLC gradient analysis
using an ion-pairing buffer system. This rigorous approach has allowed us
to identify 35S- labeled material which co-purifies with OXY and AVP from
the PVN, neural lobe, and NTS samples. Specific transport of the
nonapeptides to the NTS was demonstrated when a unilateral transection of
the hypothalamic fibers resulted in a unilateral depletion of the
radiolabeled peptides from the NTS samples. Additionally, each of the
neurophysins was purified from the neural lobe and NTS samples after linear
HPLC gradient analysis, ion-pairing buffer linear gradient analysis, then
tryptic digestion followed by exponential gradient HPLC analysis.(ABSTRACT
TRUNCATED AT 250 WORDS)