Document Detail

Facultative cardiac responses to regional hypoxia in lizard embryos.
MedLine Citation:
PMID:  20388550     Owner:  NLM     Status:  MEDLINE    
In natural nests, the eggs of squamate reptiles (lizards and snakes) sometimes experience unpredictable shifts in oxygen availability as a function of nest flooding, or the details of egg location within a nest. We experimentally investigated whether embryos can facultatively adjust cardiac function to cope with such challenges by imposing regional hypoxia on developing eggs of the scincid lizard Bassiana duperreyi. To do so, we sealed half of the eggshell surface with tissue adhesive. The embryos rapidly responded by increasing heart rates, which they maintained for long periods. The elevated heart rates enabled the embryos not only to survive, but to maintain "normal" metabolic rates, and to hatch at the usual time with unmodified phenotypic traits (e.g., hatchling size, relative heart mass, locomotor speed, post-hatchling survival and growth rates). Turtles and birds with rigid (highly calcified) eggshells show more dramatic ill-effects from hypoxic incubation, suggesting that the thin (and thus, highly gas-permeable) parchment-shelled eggs of most squamates allow more effective embryonic adjustment of oxygen exchange rates in response to externally-imposed hypoxia.
Wei-Guo Du; Michael B Thompson; Richard Shine
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-04-11
Journal Detail:
Title:  Comparative biochemistry and physiology. Part A, Molecular & integrative physiology     Volume:  156     ISSN:  1531-4332     ISO Abbreviation:  Comp. Biochem. Physiol., Part A Mol. Integr. Physiol.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-06-23     Completed Date:  2011-01-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9806096     Medline TA:  Comp Biochem Physiol A Mol Integr Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  491-4     Citation Subset:  IM    
Copyright Information:
Copyright (c) 2010 Elsevier Inc. All rights reserved.
School of Biological Sciences A08, University of Sydney, NSW 2006, Australia.
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MeSH Terms
Anoxia / metabolism*
Egg Shell
Heart / embryology*,  physiology*
Heart Rate
Lizards / embryology*,  metabolism,  physiology*
Oxygen Consumption

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