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 McKean, T.
Right arrow Articles by Park, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by McKean, T.
Right arrow Articles by Park, H.

Journal of Experimental Biology, Vol 200, Issue 19 2575-2581, Copyright © 1997 by Company of Biologists

JOURNAL ARTICLES

Hypoxia and ischaemia in buffer-perfused toad hearts

T McKean, A Scherzer and H Park
Department of Biological Sciences, University of Idaho, Moscow 83844-3051, USA.

Previous studies on the effects of ischaemia or hypoxia in ectothermic vertebrate hearts have generally used preparations that were not performing at physiological levels of pressure and flow. The conclusions that ischaemia or hypoxia are not stressful to these organisms were examined in another species, Bufo marinus, in which a buffer-perfused heart was performing physiological levels of work. The in situ preparation demonstrated the Frank-Starling relationship and mechanical characteristics similar to the hearts of intact animals. The hearts recovered from 60 min of ischaemia and reperfusion with no reduction in pressure, flow or heart rate parameters. Hearts exposed to 30 min of hypoxia at physiological filling and diastolic afterload pressures ceased generating a continuous cardiac output during the hypoxia. In most cases, there was a gradual reduction of cardiac output to zero, but in 27% of the hearts studied, intermittent beating was observed. During reoxygenation, the hearts recovered 50-90% of their prehypoxic function and were damaged. Hearts exposed to hypoxia with reduced filling and diastolic afterload continued to develop a cardiac output throughout the hypoxia and demonstrated an overshoot phenomena with the onset of reoxygenation. If demand is in the normal range at the onset of hypoxia, the hearts intrinsically reduce demand either by reducing pressure development or by conversion to intermittent beating. Toad hearts appear not to be damaged by ischaemia, a condition in which demand is low.


This article has been cited by other articles:


Home page
 J. Exp. Biol.Home page
H. A. Shiels and E. White
The Frank-Starling mechanism in vertebrate cardiac myocytes
J. Exp. Biol., July 1, 2008; 211(13): 2005 - 2013.
[Abstract] [Full Text] [PDF]

Home page
 J. Exp. Biol.Home page
T. McKean, G. Li, and K. Wei
Cardiac effects of hypoxia in the neotenous tiger salamander Ambystoma tigrinum
J. Exp. Biol., June 15, 2002; 205(12): 1725 - 1734.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
M. Vornanen and J. Tuomennoro
Effects of acute anoxia on heart function in crucian carp: importance of cholinergic and purinergic control
Am J Physiol Regulatory Integrative Comp Physiol, August 1, 1999; 277(2): R465 - R475.
[Abstract] [Full Text] [PDF]

Home page
 J. Exp. Biol.Home page
A. Gamperl, W. Milsom, A. Farrell, and T Wang
Cardiorespiratory responses of the toad (Bufo marinus) to hypoxia at two different temperatures
J. Exp. Biol., January 12, 1999; 202(24): 3647 - 3658.
[Abstract] [PDF]


© The Company of Biologists Ltd 1997