Document Detail

Comparative respiratory strategies of subterranean and fossorial octodontid rodents to cope with hypoxic and hypercapnic atmospheres.
MedLine Citation:
PMID:  20352232     Owner:  NLM     Status:  MEDLINE    
Subterranean rodents construct large and complex burrows and spend most of their lives underground, while fossorial species construct simpler burrows and are more active above ground. An important constraint faced by subterranean mammals is the chronic hypoxia and hypercapnia of the burrow atmosphere. The traits, regarded as "adaptations of rodents to hypoxia and hypercapnia", have been evaluated in only a few subterranean species. In addition, well-studied subterranean taxa are very divergent to their sister groups, making it difficult to assess the adaptive path leading to subterranean life. The closely related sister genera Octodon and Spalacopus of Neotropical rodents offer a unique opportunity to trace the evolution of physiological mechanisms. We studied the ventilatory responses of selected octodontid rodents to selective pressures imposed by the subterranean niche under the working hypothesis that life underground, in hypoxic and hypercapnic conditions, promotes convergent physiological changes. To perform this study we used the following species: Spalacopus cyanus (the subterranean coruros) and Octodon degus (the fossorial degus) from central Chile. Ventilatory tidal volume and respiratory frequency were measured in non-anaesthetized spontaneously breathing animals. Acute hypoxic challenges (O(2) 1-15%) and hypercapnia (CO(2) 10%) were induced to study respiratory strategies using non-invasive whole body pletismography techniques. Our results show that coruros have a larger ventilatory response to acute hypoxia as than degus. On the other hand, hypercapnic respiratory responses in coruros seem to be attenuated when compared to those in degus. Our results suggest that coruros and degus have different respiratory strategies to survive in the hypoxic and hypercapnic atmospheres present in their burrows.
I H Tomasco; R Del Río; R Iturriaga; F Bozinovic
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-03-30
Journal Detail:
Title:  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology     Volume:  180     ISSN:  1432-136X     ISO Abbreviation:  J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-14     Completed Date:  2010-10-28     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8413200     Medline TA:  J Comp Physiol B     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  877-84     Citation Subset:  IM    
Laboratorio de Evolución, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay.
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MeSH Terms
Adaptation, Physiological / physiology*
Anoxia / physiopathology*
Body Mass Index
Carbon Dioxide / metabolism
Hypercapnia / physiopathology*
Nitrogen / metabolism
Octodon / physiology*
Oxygen / metabolism
Pulmonary Ventilation / physiology
Respiratory Mechanics / physiology*
Rodentia / physiology*
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7727-37-9/Nitrogen; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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