|
|
||||||||
AJP - Regulatory, Integrative and Comparative Physiology, Vol 264, Issue 2 324-R330, Copyright © 1993 by American Physiological Society
ARTICLES |
H. G. Chen and C. E. Wood
Department of Physiology, University of Florida College of Medicine, Gainesville 32610-0274.
Previous studies have demonstrated that fetal adrenocorticotropic hormone (ACTH) and arginine vasopressin (AVP) are increased during periods of acidemia produced by infusion of acid intravenously or by acidemia secondary to hypovolemia. The purpose of this study was to quantify ACTH and AVP responses to hypercapnic acidemia and to test the role of the peripheral chemoreceptors in the control of these responses. Chronically catheterized fetal sheep were subjected to carotid sinus denervation and bilateral vagotomy or were studied intact. At least 5 days after surgery, fetuses were exposed to a 60-min period of normocapnia or hypercapnia, delivered via a polyethylene bag containing 5-8% CO2 in 21% O2 fitted over the head of the pregnant ewe. Hypercapnia significantly increased fetal arterial PCO2 to 55.2 +/- 1.8 and 55.9 +/- 2.2 mmHg and decreased arterial pH to 7.257 +/- 0.011 and 7.281 +/- 0.010 in intact and denervated fetuses, respectively. Fetal mean arterial blood pressure was decreased slightly in the denervated fetuses during hypercapnia. Fetal plasma AVP was increased in both groups equally, and plasma ACTH and cortisol were increased in the denervated fetuses only. Fetal heart rate was increased significantly in intact but not denervated fetuses. We conclude that respiratory acidemia is a mild stimulus to AVP secretion and that this response is not attenuated by peripheral chemodenervation.
This article has been cited by other articles:
![]() |
M. J. Powers and C. E. Wood Ketamine inhibits fetal ACTH responses to cerebral hypoperfusion Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1542 - R1549. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. E. Wood and H. Tong Central nervous system regulation of reflex responses to hypotension during fetal life Am J Physiol Regulatory Integrative Comp Physiol, December 1, 1999; 277(6): R1541 - R1552. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Schwartz and J. C. Rose Development of the pituitary adrenal axis in fetal sheep twins Am J Physiol Regulatory Integrative Comp Physiol, January 1, 1998; 274(1): R1 - R8. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |