|
|
||||||||
1 Laboratory for Pregnancy and Newborn Research, New York State College of Veterinary Medicine, Cornell University, Ithaca, New York 14853; and 2 Perinatal Research Laboratories, Department of Obstetrics and Gynecology, Harbor-UCLA Medical Center, Torrance, California 90509
We hypothesized that the
anterior circumventricular organs (ACVO) and the supraoptic (SON) and
hypothalamic paraventricular nuclei (PVN), among other structures that
play a role in sensing extracellular body fluid volume and composition
in postnatal animals (as demonstrated by Fos protein production by the
immediate-early gene c-fos), would
show similar activation in fetal sheep during an osmotic challenge. The
brains of 10 fetal sheep [6 treated, 4 controls; 129-131
days of gestational age (dGA) = 0.87 gestation] were
immunostained for Fos. Seventy-five minutes before tissue collection
the dams were given intravenous 20% mannitol (1 ml · min
1 · kg
1
for 10 min). Subsequently, the ACVO, SON, and PVN were scored for the
amount of neuronal Fos immunostaining. The subfornical organ (SFO; 24.5 ± 9.0 vs. 1.7 ± 1.2), the organum vasculosum of the lamina
terminalis (OVLT; 26.8 ± 5.6 vs. 7.0 ± 2.0), the SON (39.8 ± 3.0 vs. 0.15 ± 0.1), and the PVN (59.8 ± 7.9 vs. 0.7 ± 0.7) had increases (P < 0.05)
in the average number of Fos-positive cells per field compared with
controls, whereas the median preoptic nucleus did not. Double
immunostaining for Fos and arginine vasopressin (AVP) or oxytocin (OT)
indicated that AVP- but not OT-immunopositive neurons in SON and PVN
respond to osmotic challenge. These results demonstrate that the SFO,
OVLT, SON, and PVN are activated by osmotic challenge in fetal sheep at
130 dGA.
c-fos; paraventricular nuclei; supraoptic nuclei; swallowing
This article has been cited by other articles:
![]() |
S. Wang, J. Chen, N. Kallichanda, A. Azim, G. Calvario, and M. G. Ross Prolonged Prenatal Hypernatremia Alters Neuroendocrine and Electrolyte Homeostasis in Neonatal Sheep Experimental Biology and Medicine, January 1, 2003; 228(1): 41 - 45. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Caston-Balderrama, M. J. M. Nijland, T. J. McDonald, and M. G. Ross Intact osmoregulatory centers in the preterm ovine fetus: Fos induction after an osmotic challenge Am J Physiol Heart Circ Physiol, December 1, 2001; 281(6): H2626 - H2635. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Caston-Balderrama, M. J. M. Nijland, T. J. McDonald, and M. G. Ross Central Fos expression in fetal and adult sheep after intraperitoneal hypertonic saline Am J Physiol Heart Circ Physiol, February 1, 1999; 276(2): H725 - H735. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |