Document Detail


Cardiac Function of the Naked Mole-rat: Ecophysiological Responses to Working Underground.
MedLine Citation:
PMID:  24363308     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The naked mole-rat (NMR) is a strictly subterranean rodent with a low resting metabolic rate. Nevertheless, it can greatly increase its metabolic activity to meet the high energetic demands associated with digging through compacted soils in its xeric natural habitat where food is patchily distributed. We hypothesized that the NMR heart would naturally have low basal function and exhibit a large cardiac reserve, thereby mirroring the species' low basal metabolism and large metabolic scope. Echocardiography showed that young (2-4 year old) healthy NMRs have low fractional shortening (28 ± 2%), ejection fraction (43 ± 2%), and cardiac output (6.5 ± 0.4 ml/min), indicating low basal cardiac function. Histology revealed large NMR cardiomyocyte cross-sectional area (216 ± 10 μm(2)) and cardiac collagen deposition of 2.2 ± 0.4%. Neither of these histomorphometric traits was considered pathological, as biaxial tensile testing showed no increase in passive ventricular stiffness. NMR cardiomyocyte fibers showed a low degree of rotation, contributing to the observed low NMR cardiac contractility. Interestingly, when the exercise mimetic dobutamine (3 μg/g i.p.) was administered, NMRs showed pronounced increases in fractional shortening, ejection fraction, cardiac output, and stroke volume, indicating an increased cardiac reserve. The relatively low basal cardiac function and enhanced cardiac reserve of NMRs are likely to be ecophysiological adaptations to life in an energetically-taxing environment.
Authors:
Kelly Marie Grimes; Andrew Voorhees; Ying Ann Chiao; Hai-Chao Han; Merry L Lindsey; Rochelle Buffenstein
Related Documents :
24054508 - Epidemiology and management of cardiac arrest: what registries are revealing.
23292298 - Aquaporin 1 plays an important role in myocardial edema caused by cardiopulmonary bypas...
23304958 - Ischaemic stroke in hyperthyroidism without cardiac arrhythmia. a case report from sout...
17476008 - Intracoronary streptokinase after primary percutaneous coronary intervention.
2404638 - Heart failure with normal ejection fraction. the v-heft study. veterans administration ...
23006578 - Motor recovery mechanisms in patients with middle cerebral artery infarct: a mini-review.
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-12-20
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  -     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2013 Dec 
Date Detail:
Created Date:  2013-12-23     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:

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


Previous Document:  G-protein coupled receptors mediate coronary flow and agonist-induced responses via lectin- oligosac...
Next Document:  Fine temporal structure of cardiorespiratory synchronization.