What question did this study set out to answer?

To determine the cardiac chamber-specific functional effects of replacing endogenous atrial myosin light chain-2 with the ventricular isoform.

April 21, 1998CirculationOpen Access

Effects of Total Replacement of Atrial Myosin Light Chain-2 With the Ventricular Isoform in Atrial Myocytes of Transgenic Mice

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Population

Enzymatically disaggregated atrial and ventricular myocytes from transgenic mice and control animals

Comparison

Postnatal transgenic cardiac-specific… vs Myocytes from control animals

Design

Preclinical

Authors

CPCorinn M. Pawloski-DahmUniversity of Cincinnati GSGuojie SongJoslin Diabetes Center DKDarryl L. KirkpatrickUniversity Hospitals of Cleveland

Discussion

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Implication

Animal data preclude clinical application; leaves open MLC2v modulation as a target for atrial contractility in humans.

Key Points

To determine the cardiac chamber-specific functional effects of replacing endogenous atrial myosin light chain-2 with the ventricular isoform.
Engineered transgenic mice with postnatal, cardiac-specific overexpression of MLC2v driven by the alpha-myosin heavy chain promoter.
Measured mechanical properties and calcium transient kinetics in enzymatically isolated, field-stimulated atrial and ventricular myocytes using video edge detection and FURA 2-AM.
Overexpression of MLC2v led to the complete replacement of the native atrial isoform by the ventricular isoform at the mRNA and protein levels in atrial tissue.
Transgenic atrial myocytes displayed enhanced contractile mechanics matching the levels of control ventricular myocytes, alongside a modest reduction in calcium transient amplitude.

Structured PICO

Population

Enzymatically disaggregated atrial and ventricular myocytes from transgenic mice and control animals

Intervention

Postnatal transgenic cardiac-specific overexpression of the ventricular isoform of the regulatory myosin light chain (MLC2v) using the alpha-myosin heavy chain promoter

Comparator

Myocytes from control animals

Outcome

Mechanical properties and calcium kinetics (measured by video edge detection and FURA 2-AM)surrogate

Replacement of atrial myosin light chain-2 with the ventricular isoform enhances atrial myocyte contractility, suggesting MLC2v modulates chamber-specific contractility via enhanced calcium sensitivity or improved cross-bridge cycling.

Cite This Study

Pawloski-Dahm et al. (1998) studied this question.

synapsesocial.com/papers/6a847b0525efb1e71e83fdd8 https://doi.org/10.1161/01.cir.97.15.1508

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Effects of Total Replacement of Atrial Myosin Light Chain-2 With the Ventricular Isoform in Atrial Myocytes of Transgenic Mice

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Effects of Total Replacement of Atrial Myosin Light Chain-2 With the Ventricular Isoform in Atrial Myocytes of Transgenic Mice

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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