Document Detail

Coronary intercapillary distance during growth: relation to PtO2 and aerobic capacity.
MedLine Citation:
PMID:  990126     Owner:  NLM     Status:  MEDLINE    
Intercapillary distance (ICD) was measured in left ventricles of rats beating in situ. Between 40 and 400 days of age, left ventricular weight increased threefold and ICD increased from 12.5-19.5 mum. ICD could be decreased by at least 2 mum at all ages studied. The number of capillaries which must be recruited to reduce ICD by 2 mum fell from 1,200/mm2 at 40 days to 280/mm2 at 400 days. Ventricular growth did not affect the O2 sensitivity of precapillary sphincters or the uniformity of capillary spacing. Calculations indicate that under basal conditions tissue PO2 (Pto2) in subepicardium is about the same at 40 and 400 days, even though VO2 per gram, capillary density, and ICD change twofold, twofold, and 7 mum, respectively. Nevertheless, as the ventricle grows, capillary recruitment becomes progressively less effective in defending Pto2 under conditions of stress. Diminished coronary capillary compensation for stress may, in part, account for the effect of age on the maximum aerobic capacity of the whole animal.
L Henquell; C L Odoroff; C R Honig
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  231     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1976 Dec 
Date Detail:
Created Date:  1977-02-16     Completed Date:  1977-02-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1852-9     Citation Subset:  IM    
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MeSH Terms
Capillaries / anatomy & histology
Coronary Vessels / anatomy & histology*
Heart / growth & development*
Oxygen* / blood
Partial Pressure
Reg. No./Substance:

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