Journal of Applied Physiology Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 62: 1033-1039, 1987;
8750-7587/87 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Koos, B. J.
Right arrow Articles by Power, G. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Koos, B. J.
Right arrow Articles by Power, G. G.

Journal of Applied Physiology, Vol 62, Issue 3 1033-1039, Copyright © 1987 by American Physiological Society

ARTICLES

Fetal breathing, sleep state, and cardiovascular responses to graded hypoxia in sheep

B. J. Koos, H. Sameshima and G. G. Power

Graded isocapnic hypoxemia was produced in unanesthetized fetal sheep by varying the inspired O2 concentration (21, 12, 10.5, and 9%) of the ewe. This produced corresponding mean preductal arterial O2 tension (PaO2) values of 25.2 +/- 1.1 (control), 20.1 +/- 1.0 (mild hypoxia), 17.8 +/- 0.9 (moderate hypoxia), and 16.8 +/- 1.4 Torr (severe hypoxia). These were associated with mean arterial O2 contents (CaO2) of 7.18 +/- 0.44, 5.19 +/- 0.34, 4.24 +/- 0.33, and 3.27 +/- 0.20 ml/dl, respectively. The most severe hypoxia was associated with metabolic acidosis and fetal bradycardia. Hypoxia did not reduce significantly the incidence of low-voltage electrocortical activity. The incidence of breathing and rapid eye movements was not affected by mild hypoxia; however, the incidence of both was significantly reduced during moderate and severe hypoxia. It is concluded that 1) acute reductions in the mean PaO2 of 5.9 +/- 0.6 Torr and CaO2 of 2.00 +/- 0.23 ml/dl are critical in that greater reductions inhibit fetal eye and breathing activity and 2) hypoxia probably inhibits eye and breathing movements by altering sleep state.


This article has been cited by other articles:


Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
B. J. Koos and T. Maeda
Adenosine A2A receptors mediate cardiovascular responses to hypoxia in fetal sheep
Am J Physiol Heart Circ Physiol, January 1, 2001; 280(1): H83 - H89.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
J. M. Bissonnette
Mechanisms regulating hypoxic respiratory depression during fetal and postnatal life
Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2000; 278(6): R1391 - R1400.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
B. J. Koos, A. Chau, M. Matsuura, O. Punla, and L. Kruger
Thalamic lesions dissociate breathing inhibition by hypoxia and adenosine in fetal sheep
Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2000; 278(4): R831 - R837.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
A. Chau and B. J. Koos
Metabolic and cardiorespiratory responses to hypoxia in fetal sheep: adenosine receptor blockade
Am J Physiol Regulatory Integrative Comp Physiol, June 1, 1999; 276(6): R1805 - R1811.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
B. J. Koos and A. Chau
Fetal cardiovascular and breathing responses to an adenosine A2a receptor agonist in sheep
Am J Physiol Regulatory Integrative Comp Physiol, January 1, 1998; 274(1): R152 - R159.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online