ROK-induced cross-link formation stiffens passive muscle: reversible strain-induced stress softening in rabbit detrusor

• DOI: 10.1152/ajpcell.00418.2004
• Publication Date: 2005-02-17T01:23:53Z
• Authors: John E. Speich; Lindsey Borgsmiller; Chris Call; Ryan Mohr; Paul H. Ratz
• Keywords: Muscle stiffness; Strain (injury)

Passive mechanical properties of strips rabbit detrusor smooth muscle were examined and found by cyclic loading in a calcium-free solution to display viscoelastic softening strain-induced stress (strain softening). Strain softening, or the Mullins effect, is loss stiffness attributed breakage cross-links, appeared irreversible even after return spontaneous rhythmic tone during 120 min incubation calcium-containing solution. However, 3 KCl carbachol (CCh)-induced contraction permitted rapid regeneration passive lost strain microM RhoA kinase (ROK) inhibitor Y-27632 prevented this regeneration. The degree ROK-induced was inversely dependent on length over range where peak CCh-induced force independent. Thus displayed variable both strain- activation-history dependent. In conclusion, activation ROK CCh increased softened thereby cross-links that remained stable tissue Degradation signaling system could potentially contribute urinary incontinence.