AJP - Regu Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 276: R1805-R1811, 1999;
0363-6119/99 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
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 Chau, A.
Right arrow Articles by Koos, B. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chau, A.
Right arrow Articles by Koos, B. J.
Vol. 276, Issue 6, R1805-R1811, June 1999

Metabolic and cardiorespiratory responses to hypoxia in fetal sheep: adenosine receptor blockade

Andrew Chau and Brian J. Koos

Department of Obstetrics and Gynecology, Nicholas S. Assali Perinatal Research Laboratory, and School of Medicine, The Brain Research Institute, University of California, Los Angeles, California 90095-1740

8-Phenyltheophylline (PT), a potent and specific inhibitor of adenosine receptors, was infused intra-arterially into unanesthetized fetal sheep to determine the role of adenosine in hypoxic inhibition of fetal breathing. PT in normoxic fetuses increased heart rate and the incidence of low-voltage electrocortical activity, rapid eye movements (REM), and breathing. Mean breath amplitude increased by 44%. Hypoxia (preductal arterial PO2 = 14 Torr) induced a metabolic acidemia, a transient bradycardia, and hypertension while virtually eliminating REM and breathing. PT administration during hypoxia enhanced the metabolic acidemia, blocked the bradycardia and hypertension, increased the incidence of REM and breathing, and elevated mean breath amplitude. The results indicate that 1) adenosine is involved in fetal glycolytic and cardiovascular responses to hypoxia, 2) activation of central adenosine receptors mediates about one-half the inhibitory effects of hypoxia on REM and breathing, and 3) the depression of breathing may critically depend on a hypoxia-induced reduction in phasic REM sleep.

heart rate; blood pressure; brain; breathing; eye movements; sleep; thalamus


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
B. J. Koos, Y. Kawasaki, Y.-H. Kim, and F. Bohorquez
Adenosine A2A-receptor blockade abolishes the roll-off respiratory response to hypoxia in awake lambs
Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2005; 288(5): R1185 - R1194.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
B. J. Koos, T. Maeda, and C. Jan
Adenosine A1 and A2A receptors modulate sleep state and breathing in fetal sheep
J Appl Physiol, July 1, 2001; 91(1): 343 - 350.
[Abstract] [Full Text] [PDF]

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