title: Alterations in pulmonary surfactant after rapid arousal from torpor in the marsupial Sminthopsis crassicaudata.
abstract: Torpor in the dunnart, Sminthopsis crassicaudata, alters surfactant lipid composition and surface activity. Here we investigated changes in surfactant composition and surface activity over 1 h after rapid arousal from torpor (15-30 degrees C at 1 degrees C/min). We measured total phospholipid (PL), disaturated PL (DSP), and cholesterol (Chol) content of surfactant lavage and surface activity (measured at both 15 and 37 degrees C in the captive bubble surfactometer). Immediately after arousal, Chol decreased (from 4.1 +/- 0.05 to 2.8 +/- 0.3 mg/g dry lung) and reached warm-active levels by 60 min after arousal. The Chol/DSP and Chol/PL ratios both decreased to warm-active levels 5 min after arousal because PL, DSP, and the DSP/PL ratio remained elevated over the 60 min after arousal. Minimal surface tension and film compressibility at 17 mN/m at 37 degrees C both decreased 5 min after arousal, correlating with rapid changes in surfactant Chol. Therefore, changes in lipids matched changes in surface activity during the postarousal period.
authors.affiliation: Department of Physiology, The University of Adelaide, Adelaide, South Australia 5005. olga.lopatko@adelaide.edu.au
authors.forename: O V
authors.initials: OV
authors.lastname: Lopatko
authors.forename: S
authors.initials: S
authors.lastname: Orgeig
authors.forename: D
authors.initials: D
authors.lastname: Palmer
authors.forename: S
authors.initials: S
authors.lastname: Schürch
authors.forename: C B
authors.initials: CB
authors.lastname: Daniels
mesh_terms: D000327:Adsorption; D000818:Animals; D001143:Arousal / Q000502:physiology*; D001831:Body Temperature; D002784:Cholesterol / Q000032:analysis; D006605:Hibernation / Q000502:physiology*; D008055:Lipids / Q000032:analysis; D008297:Male; D008394:Marsupialia / Q000502:physiology*; D010743:Phospholipids / Q000032:analysis; D011663:Pulmonary Surfactants / Q000737:chemistry / Q000378:metabolism*; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D008055:Lipids; D010743:Phospholipids; D011663:Pulmonary Surfactants; D002784:Cholesterol