What does this research mean for the field?

During agonist activation of smooth muscle, the maintenance of enhanced force and myofilament Ca2+ sensitivity requires additional mechanisms beyond myosin light chain (MLC) phosphorylation, as force remains elevated even after MLC phosphorylation transiently returns to baseline levels. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This study aims to explore the relationship between force, myosin light chain phosphorylation, and calcium sensitivity during artery contractions.

August 1, 1992AJP Cell Physiology

Transient myosin phosphorylation at constant Ca2+ during agonist activation of permeabilized arteries

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Why the study?

Does NE plus GTP alter force, MLC phosphorylation, stiffness, and shortening velocity compared to Ca2+ alone in permeabilized rabbit mesenteric arteries?

Population

alpha-toxin-permeabilized rabbit mesenteric arteries

Comparison

Norepinephrine plus guanosine triphosphate in… vs Ca2+ alone

Design

Preclinical

Authors

SMSuzanne MorelandBristol-Myers Squibb (United States)JNJunji NishimuraFukuoka Institute of Technology CBC. van BreemenBurnaby Hospital

Discussion

Member takes

Implication

Points to myofilament mechanisms beyond MLC phosphatase for sustained Ca2+ sensitization; leaves open relevance to human vascular tone.

Key Points

This study aims to explore the relationship between force, myosin light chain phosphorylation, and calcium sensitivity during artery contractions.
Used alpha-toxin-permeabilized rabbit mesenteric arteries.
Analyzed force, myosin light chain phosphorylation, stiffness, and shortening velocity in response to calcium alone and in the presence of norepinephrine plus GTP.
Norepinephrine plus GTP increased tonic contraction and transiently elevated MLC phosphorylation compared to calcium alone.
Both force and stiffness increased similarly with norepinephrine plus GTP, while shortening velocity was dependent on calcium concentration.
MLC phosphorylation levels returned to those seen with calcium alone, indicating other factors maintain enhanced force.

Structured PICO

Does NE plus GTP alter force, MLC phosphorylation, stiffness, and shortening velocity compared to Ca2+ alone in permeabilized rabbit mesenteric arteries?

Population

alpha-toxin-permeabilized rabbit mesenteric arteries

Intervention

Norepinephrine (NE) plus guanosine triphosphate (GTP) in the presence of Ca2+

Comparator

Ca2+ alone

Outcome

Temporal relationships among force, myosin light chain (MLC) phosphorylation, stiffness, and shortening velocitysurrogate

The maintenance of receptor and G protein-dependent increase in myofilament Ca2+ sensitivity involves additional elements beyond regulated MLC phosphatase, as enhanced force is maintained despite falling MLC phosphorylation levels.

Cite This Study

Moreland et al. (1992) studied this question.

synapsesocial.com/papers/6a1e40bf7f6e8bbb2368aff3 https://doi.org/10.1152/ajpcell.1992.263.2.c540

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Transient myosin phosphorylation at constant Ca2+ during agonist activation of permeabilized arteries

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Transient myosin phosphorylation at constant Ca2+ during agonist activation of permeabilized arteries

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

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