Structure-function correlation in airway smooth muscle adapted to different lengths.

TitleStructure-function correlation in airway smooth muscle adapted to different lengths.
Publication TypeJournal Article
Year of Publication2003
AuthorsKuo, K-H, Herrera, AM, Wang, L, Paré, PD, Ford, LE, Stephens, NL, Seow, CY
JournalAm J Physiol Cell Physiol
Date Published2003 Aug
KeywordsAdaptation, Physiological, Adenosine Triphosphatases, Animals, Biomechanical Phenomena, Cell Size, Cytoskeleton, Dogs, Isometric Contraction, Microscopy, Electron, Models, Biological, Myocytes, Smooth Muscle, Myosins, Respiratory Physiological Phenomena, Sus scrofa, Tensile Strength, Trachea

Airway smooth muscle is able to adapt and maintain a nearly constant maximal force generation over a large length range. This implies that a fixed filament lattice such as that found in striated muscle may not exist in this tissue and that plastic remodeling of its contractile and cytoskeletal filaments may be involved in the process of length adaptation that optimizes contractile filament overlap. Here, we show that isometric force produced by airway smooth muscle is independent of muscle length over a twofold length change; cell cross-sectional area was inversely proportional to cell length, implying that the cell volume was conserved at different lengths; shortening velocity and myosin filament density varied similarly to length change: increased by 69.4% +/- 5.7 (SE) and 76.0% +/- 9.8, respectively, for a 100% increase in cell length. Muscle power output, ATPase rate, and myosin filament density also have the same dependence on muscle cell length: increased by 35.4% +/- 6.7, 34.6% +/- 3.4, and 35.6% +/- 10.6, respectively, for a 50% increase in cell length. The data can be explained by a model in which additional contractile units containing myosin filaments are formed and placed in series with existing contractile units when the muscle is adapted at a longer length.

Alternate JournalAm. J. Physiol., Cell Physiol.
PubMed ID12700138