| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Departments of Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, IN, USA
2 Department of Mechanical Engineering, Purdue School of Engineering and Technology, IUPUI, Indianapolis, IN, USA
* To whom correspondence should be addressed. E-mail: igeq100{at}iupui.edu.
While the shortening of smooth muscle at physiological lengths is dominated by an interaction between external forces (loads) and internal forces, at very short lengths internal forces appear to dominate the mechanical behavior of the active tissue. We tested the hypothesis that, under conditions of extreme shortening and low external force, the mechanical behavior of isolated canine tracheal smooth muscle tissue can be understood as a structure in which the force borne and exerted by the crossbridge and myofilament array is opposed by radially-disposed connective tissue, in the presence of an incompressible fluid matrix (cellular and extracellular). Strips of electrically stimulated tracheal muscle were allowed to shorten maximally under very low afterload, and large longitudinal sinusoidal vibrations (34 Hz, 1 second in duration, and up to 50% of the muscle length prior to vibration) were applied to highly shortened (active) tissue strips in order to produce reversible crossbridge detachment. During the vibration, peak muscle force fell exponentially with successive forced elongations. Following the episode, the muscle either extended itself or exerted a force against the tension transducer, depending on external conditions. The magnitude of this effect was proportional to the prior muscle stiffness and the amplitude of the vibration, indicating a recoil of strained connective tissue elements no longer opposed by crossbridge forces. This behavior suggests that mechanical behavior at short lengths is dominated by tissue forces within a tensegrity-like structure made up of connective tissue, other extracellular matrix components, and active contractile elements.
This article has been cited by other articles:
|
|
 |
|
  A. L. James and S. Wenzel Clinical relevance of airway remodelling in airway diseases Eur. Respir. J., July 1, 2007; 30(1): 134 - 155. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. E. Speich, K. Quintero, C. Dosier, L. Borgsmiller, H. P. Koo, and P. H. Ratz A mechanical model for adjustable passive stiffness in rabbit detrusor J Appl Physiol, October 1, 2006; 101(4): 1189 - 1198. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Wang, P. Chitano, and T. M. Murphy Maturation of guinea pig tracheal strip stiffness Am J Physiol Lung Cell Mol Physiol, December 1, 2005; 289(6): L902 - L908. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. M. Herrera, B. E. McParland, A. Bienkowska, R. Tait, P. D. Pare, and C. Y. Seow `Sarcomeres' of smooth muscle: functional characteristics and ultrastructural evidence J. Cell Sci., June 1, 2005; 118(11): 2381 - 2392. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Meiss and R. M. Pidaparti Active and passive components in the length-dependent stiffness of tracheal smooth muscle during isotonic shortening J Appl Physiol, January 1, 2005; 98(1): 234 - 241. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
