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


     

Am J Physiol Regul Integr Comp Physiol (August 8, 2002). doi:10.1152/ajpregu.00167.2002
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
283/5/R1254    most recent
00167.2002v1
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
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Mark, F.
Right arrow Articles by Portner, H. O
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mark, F.
Right arrow Articles by Portner, H. O

Articles in PresS, published online ahead of print August 8, 2002
Am J Physiol Regu Physiol, 10.1152/ajpregu.00167.2002
Submitted on March 15, 2002
Accepted on July 31, 2002

Oxygen limited thermal tolerance in Antarctic fish investigated by magnetic resonance imaging (MRI) and spectroscopy (31P-MRS)

Felix Mark1, Christian Bock1, and Hans O Portner1*

1 Ecophysiology and Ecotoxicology, Alfred-Wegener-Institute, Bremerhaven, Germany

* To whom correspondence should be addressed. E-mail: hpoertner{at}awi-bremerhaven.de.

The hypothesis of an oxygen limited thermal tolerance was tested in the Antarctic teleost Pachycara brachycephalum. Using flow-through respirometry, in vivo 31P-NMR spectroscopy and MRI, we studied energy metabolism, intracellular pH (pHi), blood-flow and oxygenation between 0 and 13°C under normoxia (PO2: 20,3 to 21,3kPa) and hyperoxia (PO2: 45kPa). Hyperoxia reduced the metabolic increment and the rise in arterial blood-flow observed under normoxia. The normoxic increase of blood-flow levelled off beyond 7°C, indicating a cardiovascular capacity limitation. Ventilatory effort displayed an exponential rise in both groups. In the liver, blood oxygenation increased, whereas in white muscle it remained unaltered (normoxia) or declined (hyperoxia). In both groups, the slope of pHi changes followed the alpha-stat pattern below 6°C, whereas it decreased above. In conclusion, aerobic scope declines around 6°C under normoxia, marking the pejus temperature Tp. By reducing circulatory costs, hyperoxia improves aerobic scope but is unable to shift the breakpoint in pH regulation or lethal limits. Hyperoxia appears beneficial at sublethal temperatures, but no longer beyond when cellular or molecular functions become disturbed.




This article has been cited by other articles:


Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
E. Sandblom and M. Axelsson
Venous hemodynamic responses to acute temperature increase in the rainbow trout (Oncorhynchus mykiss)
Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2007; 292(6): R2292 - R2298.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
Y. Yoshioka, H. Oikawa, S. Ehara, T. Inoue, A. Ogawa, Y. Kanbara, and M. Kubokawa
Noninvasive measurement of temperature and fractional dissociation of imidazole in human lower leg muscles using 1H-nuclear magnetic resonance spectroscopy
J Appl Physiol, January 1, 2005; 98(1): 282 - 287.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
G. Lannig, C. Bock, F. J. Sartoris, and H. O. Portner
Oxygen limitation of thermal tolerance in cod, Gadus morhua L., studied by magnetic resonance imaging and on-line venous oxygen monitoring
Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2004; 287(4): R902 - R910.
[Abstract] [Full Text] [PDF]

Home page
 J. Exp. Biol.Home page
I. A. Johnston, D. A. Fernandez, J. Calvo, V. L. A. Vieira, A. W. North, M. Abercromby, and T. Garland Jr
Reduction in muscle fibre number during the adaptive radiation of notothenioid fishes: a phylogenetic perspective
J. Exp. Biol., August 1, 2003; 206(15): 2595 - 2609.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 2002 by the American Physiological Society.