spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
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
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Herman, J. K.
Right arrow Articles by Smatresk, N. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Herman, J. K.
Right arrow Articles by Smatresk, N. J.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Journal of Experimental Biology, Vol 202, Issue 22 3205-3213, Copyright © 1999 by Company of Biologists

JOURNAL ARTICLES

Cardiorespiratory response to progressive hypoxia and hypercapnia in the turtle trachemys scripta

JK Herman and NJ Smatresk
Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA. HermanJ@svm.vetmed.wisc.edu.

The ventilatory responses of chelonian reptiles to hypoxic and hypercapnic stress have been fairly well described. As turtles are capable of large cardiac shunts, changes in pulmonary perfusion may be an equally viable and potent response to these stressors. To test this hypothesis, conscious unrestrained turtles were unidirectionally ventilated while blood flow in the left pulmonary artery ( q_dot (LPA)) and left aortic arch ( q_dot (LAo)) was monitored. Turtles were exposed to step changes (2.5 h step(-)(1)) in O(2) tension (30, 15, 5, 2.5 or 0 % O(2); CO(2) inflow maintained constant) on day 1 followed by step changes in CO(2) tension (0, 2, 4, 8 % CO(2); O(2) inflow maintained constant) on day 2. Steady-state cardiorespiratory variables were recorded for the last 30 min of each step change in gas tension.Progressive hypoxia resulted in progressive increases in ventilation, q_dot (LPA) and q_dot (LAo) and a small, but non-significant, increase in heart rate. Progressive hypercapnia resulted in a progressive increase in ventilation, while q_dot (LPA) and q_dot (LAo) did not change at any level of CO(2). These results suggest that information from the O(2)-sensitive chemoreceptors appears to be stimulatory to both the cardiovascular and ventilatory control systems, while CO(2) chemoreception appears to affect primarily the ventilatory control system. These results also suggest that, in animals capable of intracardiac shunting, increasing pulmonary perfusion may be an integral component of the reflex response to hypoxia.
Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
B. Platzack and J. W. Hicks
Reductions in systemic oxygen delivery induce a hypometabolic state in the turtle Trachemys scripta
Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2001; 281(4): R1295 - R1301.
[Abstract] [Full Text] [PDF]


© The Company of Biologists Ltd 1999