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


     

J Appl Physiol 66: 1065-1070, 1989;
8750-7587/89 $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
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 Google Scholar
Google Scholar
Right arrow Articles by Massik, J.
Right arrow Articles by Traystman, R. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Massik, J.
Right arrow Articles by Traystman, R. J.

Journal of Applied Physiology, Vol 66, Issue 3 1065-1070, Copyright © 1989 by American Physiological Society

ARTICLES

Hypercapnia and response of cerebral blood flow to hypoxia in newborn lambs

J. Massik, M. D. Jones Jr, M. Miyabe, Y. L. Tang, M. L. Hudak, R. C. Koehler and R. J. Traystman
Department of Pediatrics, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205.

Individual effects of hypoxic hypoxia and hypercapnia on the cerebral circulation are well described, but data on their combined effects are conflicting. We measured the effect of hypoxic hypoxia on cerebral blood flow (CBF) and cerebral O2 consumption during normocapnia (arterial PCO2 = 33 +/- 2 Torr) and during hypercapnia (60 +/- 2 Torr) in seven pentobarbital-anesthetized lambs. Analysis of variance showed that neither the magnitude of the hypoxic CBF response nor cerebral O2 consumption was significantly related to the level of arterial PCO2. To determine whether hypoxic cerebral vasodilation during hypercapnia was restricted by reflex sympathetic stimulation we studied an additional six hypercapnic anesthetized lambs before and after bilateral removal of the superior cervical ganglion. Sympathectomy had no effect on base-line CBF during hypercapnia or on the CBF response to hypoxic hypoxia. We conclude that the effects of hypoxic hypoxia on CBF and cerebral O2 consumption are not significantly altered by moderate hypercapnia in the anesthetized lamb. Furthermore, we found no evidence that hypercapnia results in a reflex increase in sympathetic tone that interferes with the ability of cerebral vessels to dilate during hypoxic hypoxia.




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