Document Detail


Alterations in the surface properties of lung surfactant in the torpid marsupial Sminthopsis crassicaudata.
MedLine Citation:
PMID:  9451629     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Torpor changes the composition of pulmonary surfactant (PS) in the dunnart Sminthopsis crassicaudata [C. Langman, S. Orgeig, and C. B. Daniels. Am. J. Physiol. 271 (Regulatory Integrative Comp. Physiol, 40): R437-R445, 1996]. Here we investigated the surface activity of PS in vitro. Five micrograms of phospholipid per centimeter squared surface area of whole lavage (from mice or from warm-active, 4-, or 8-h torpid dunnarts) were applied dropwise onto the sub-phase of a Wilhelmy-Langmuir balance at 20 degrees C and stabilized for 20 min. After 4 h of torpor, the adsorption rate increased, and equilibrium surface tension (STeq), minimal surface tension (STmin), and the %area compression required to achieve STmin decreased, compared with the warm-active group. After 8 h of torpor, STmin decreased [from 5.2 +/- 0.3 to 4.1 +/- 0.3 (SE) mN/m]; %area compression required to achieve STmin decreased (from 43.4 +/- 1.0 to 27.4 +/- 0.8); the rate of adsorption decreased; and STeq increased (from 26.3 +/- 0.5 to 38.6 +/- 1.3 mN/m). ST-area isotherms of warm-active dunnarts and mice at 20 degrees C had a shoulder on compression and a plateau on expansion. These disappeared on the isotherms of torpid dunnarts. Samples of whole lavage (from warm-active and 8-h torpor groups) containing 100 micrograms phospholipid/ml were studied by using a captive-bubble surfactometer at 37 degrees C. After 8 h of torpor, STmin increased (from 6.4 +/- 0.3 to 9.1 +/- 0.3 mN/m) and %area compression decreased in the 2nd (from 88.6 +/- 1.7 to 82.1 +/- 2.0) and 3rd (from 89.1 +/- 0.8 to 84.9 +/- 1.8) compression-expansion cycles, compared with warm-active dunnarts. ST-area isotherms of warm-active dunnarts at 37 degrees C did not have a shoulder on compression. This shoulder appeared on the isotherms of torpid dunnarts. In conclusion, there is a strong correlation between in vitro changes in surface activity and in vivo changes in lipid composition of PS during torpor, although static lung compliance remained unchanged (see Langman et al. cited above). Surfactant from torpid animals is more active at 20 degrees C and less active at 37 degrees C than that of warm-active animals, which may represent a respiratory adaptation to low body temperatures of torpid dunnarts.
Authors:
O V Lopatko; S Orgeig; C B Daniels; D Palmer
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  84     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1998 Jan 
Date Detail:
Created Date:  1998-03-20     Completed Date:  1998-03-20     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  146-56     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Adelaide, South Australia, Australia.
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MeSH Terms
Descriptor/Qualifier:
1,2-Dipalmitoylphosphatidylcholine
Adsorption
Animals
Body Composition / physiology
Body Temperature / physiology
Chemistry, Physical
Lipids / chemistry
Male
Marsupialia / physiology*
Phosphorus / chemistry
Physicochemical Phenomena
Pulmonary Surfactants / chemistry*
Surface Properties
Surface Tension
Temperature
Chemical
Reg. No./Substance:
0/Lipids; 0/Pulmonary Surfactants; 2644-64-6/1,2-Dipalmitoylphosphatidylcholine; 7723-14-0/Phosphorus

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