scholarly journals Ontogenesis of myosin light chain phosphorylation in guinea pig tracheal smooth muscle

2005 ◽  
Vol 39 (2) ◽  
pp. 108-116 ◽  
Author(s):  
Pasquale Chitano ◽  
Charles L. Worthington ◽  
Janet A. Jenkin ◽  
Newman L. Stephens ◽  
Sylvia Gyapong ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Tracheal Smooth Muscle ◽  
Myosin Light Chain Phosphorylation

Blebbistatin, a myosin II inhibitor, suppresses contraction and disrupts contractile filaments organization of skinned taenia cecum from guinea pig

2010 ◽  
Vol 298 (5) ◽  
pp. C1118-C1126 ◽  
Author(s):  
Masaru Watanabe ◽  
Masatoshi Yumoto ◽  
Hideyuki Tanaka ◽  
Hon Hui Wang ◽  
Takeshi Katayama ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Muscle Contraction ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Smooth Muscle Contraction ◽  
Myosin Light Chain Phosphorylation ◽  
Thin Filaments ◽  
Tension Development

To explore the precise mechanisms of the inhibitory effects of blebbistatin, a potent inhibitor of myosin II, on smooth muscle contraction, we studied the blebbistatin effects on the mechanical properties and the structure of contractile filaments of skinned (cell membrane permeabilized) preparations from guinea pig taenia cecum. Blebbistatin at 10 μM or higher suppressed Ca2+-induced tension development at any given Ca2+ concentration but had little effects on the Ca2+-induced myosin light chain phosphorylation. Blebbistatin also suppressed the 10 and 2.75 mM Mg2+-induced, “myosin light chain phosphorylation-independent” tension development at more than 10 μM. Furthermore, blebbistatin induced conformational change of smooth muscle myosin (SMM) and disrupted arrangement of SMM and thin filaments, resulting in inhibition of actin-SMM interaction irrespective of activation with Ca2+. In addition, blebbistatin partially inhibited Mg2+-ATPase activity of native actomyosin from guinea pig taenia cecum at around 10 μM. These results suggested that blebbistatin suppressed skinned smooth muscle contraction through disruption of structure of SMM by the agent.

Effect of muscle length on isometric stress and myosin light chain phosphorylation in gallbladder smooth muscle

1991 ◽  
Vol 260 (6) ◽  
pp. G920-G924 ◽  
Author(s):  
R. J. Washabau ◽  
M. B. Wang ◽  
C. L. Dorst ◽  
J. P. Ryan
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Muscle Length ◽  
Stress Sensitivity ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Myosin Light Chain Phosphorylation ◽  
Myofilament Activation

These experiments were designed to characterize the effect of muscle length on isometric stress, sensitivity to stimulation, and phosphorylation of the 20,000-Da myosin light chains in guinea pig gallbladder smooth muscle. Basal, active, and total isometric stress were determined in acetylcholine- or K(+)-treated (10(-4) M ACh, 80 mM KCl) muscle strips at 0.6-1.3 times the optimal muscle length (Lo) for isometric stress development. The effect of muscle length on the sensitivity to ACh and K+ was determined in cumulative dose-response experiments (10(-8) to 10(-4) M ACh, 10-80 mM KCl) at 0.7, 1.0, and 1.3 Lo. The effect of muscle length on myosin light chain phosphorylation was determined in ACh- or K(+)-treated (10(-4) M ACh, 80 mM KCl) muscle strips at 0.7, 1.0, and 1.3 Lo. In gallbladder smooth muscle, 1) active isometric stresses at 0.7 and 1.3 Lo were less than active isometric stress at 1.0 Lo; 2) the sensitivity of developed stress was similar at 1.0 and 1.3 Lo but decreased at 0.7 Lo; 3) the decline in isometric stress and sensitivity at 0.7 Lo was associated with reduced levels of phosphorylated myosin light chain; and 4) the decline in isometric stress at 1.3 Lo was not associated with reduced amounts of phosphorylated myosin light chain. These results suggest that the decline in active stress and sensitivity at short muscle lengths (L less than Lo) in gallbladder smooth muscle is due, at least in part, to decreases in the activation of the myofilaments. The decline in active isometric stress at long muscle lengths (L greater than Lo) is not due to changes in myofilament activation.

Myosin light chain phosphorylation and contraction of guinea pig gallbladder smooth muscle

1991 ◽  
Vol 261 (6) ◽  
pp. G952-G957
Author(s):  
R. J. Washabau ◽  
M. B. Wang ◽  
J. P. Ryan
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Light Chain ◽  
Myosin Light Chain ◽  
State Level ◽  
Myosin Light Chain Phosphorylation ◽  
Shortening Velocity ◽  
Cross Bridges ◽  
Contraction And Relaxation ◽  
Isotonic Shortening

These experiments were designed to determine 1) whether acetylcholine (ACh) stimulation is accompanied by changes in myosin light chain phosphorylation in gallbladder smooth muscle and 2) whether dephosphorylated noncycling cross bridges (latch bridges) exist in gallbladder smooth muscle. Isometric stress, isotonic shortening velocity, and myosin light chain phosphorylation were determined under conditions of contraction and relaxation in ACh-stimulated guinea pig gallbladder smooth muscle. Unstimulated muscle contained 6.8 +/- 2.0% phosphorylated myosin light chain. ACh stimulation (5 x 10(-5) or 10(-4) M) was associated with a rapid increase in myosin light chain phosphorylation to a value that was maintained throughout the tonic contraction. In contrast, isotonic shortening velocity was maximal at 30 s of stimulation and then declined over time to a steady-state level that was 25-30% of the peak velocity. Upon agonist washout (relaxation), dephosphorylation of the myosin light chain occurred at about the same rate as the decline in shortening velocity and preceded the decline in isometric stress. These data suggest that ACh stimulation is accompanied by changes in myosin light chain phosphorylation but that dephosphorylation of cross bridges is not necessary for the slowing of cross-bridge cycling rates in gallbladder smooth muscle.

scholarly journals Inhibition of Contraction and Myosin Light Chain Phosphorylation in Guinea‐Pig Smooth Muscle by p21‐Activated Kinase 1

2003 ◽  
Vol 549 (2) ◽  
pp. 489-500 ◽  
Author(s):  
A. Wirth ◽  
M. Schroeter ◽  
C. Kock‐Hauser ◽  
E. Manser ◽  
J. M. Chalovich ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Light Chain Phosphorylation ◽  
P21 Activated Kinase

scholarly journals Ontogenesis of myosin light chain kinase mRNA and protein content in guinea pig tracheal smooth muscle

2004 ◽  
Vol 38 (6) ◽  
pp. 456-464 ◽  
Author(s):  
Pasquale Chitano ◽  
Judith A. Voynow ◽  
Valeria Pozzato ◽  
Viviana Cantillana ◽  
Lauranell H. Burch ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Protein Content ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Tracheal Smooth Muscle
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