Document Detail


Characterization of intact mesenteric lymphatic pump and its responsiveness to acute edemagenic stress.
MedLine Citation:
PMID:  2603989     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The contractile properties of the mesenteric collecting lymphatics of the rat were analyzed under control conditions and during periods of enhanced lymph formation using in vivo microscopic techniques. Pressure and diameter were simultaneously monitored in microscopic collecting lymphatics, and lymphatic pump function was analyzed in accordance with basic principles of cardiac mechanics. The lymphatic contractile cycle was divided into two phases of systole and four phases of diastole. Under control conditions, lymphatics contracted with a frequency of 6.4 +/- 0.61 beats/min and ejected approximately 67% of their end-diastolic volume. Ten minutes after the rate of lymph formation was elevated by plasma dilution, end-diastolic diameter, contraction frequency, ejection fraction, and stroke volume increased. Pressure in the lymphatic network became less pulsatile in high lymph flow states. Contractility, an index of inotropic changes in lymphatic pump, was unaltered when lymph flow was increased by plasma dilution. Furthermore, the maximal shortening velocity of lymphatic smooth muscle did not change during periods of enhanced lymph flow. Thus it appears that passive increases in the rate of lymph formation exert few, if any, inotropic effects on the lymphatic pump. The augmented stroke volume and contraction frequency appear to result mainly from intrinsic stretch-dependent mechanisms set in motion by elevated preload. These data represent the first comprehensive characterization of both the flow-generating and muscle characteristics of intact collecting lymphatics and provide a basis for future studies on the physiological regulation of lymphatic contraction.
Authors:
J N Benoit; D C Zawieja; A H Goodman; H J Granger
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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:  257     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1989 Dec 
Date Detail:
Created Date:  1990-02-02     Completed Date:  1990-02-02     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H2059-69     Citation Subset:  IM    
Affiliation:
Microcirculation Research Institute, College of Medicine, Texas A & M University, College Station 77843.
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MeSH Terms
Descriptor/Qualifier:
Animals
Diastole
Lymph / physiology
Lymphatic System / physiology*,  physiopathology
Lymphedema / physiopathology*
Male
Models, Biological
Muscle Contraction
Muscle, Smooth / physiology,  physiopathology
Pressure
Rats
Rats, Inbred Strains
Systole
Time Factors
Grant Support
ID/Acronym/Agency:
HL-07247/HL/NHLBI NIH HHS; HL-07688/HL/NHLBI NIH HHS; HL-21498/HL/NHLBI NIH HHS

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


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