What is the clinical evidence from this study?

Intervention: Inactivation of INa vs. Presence of INa / NCX KO cells. Primary outcome: Ca(2+) transient amplitude (51.1% decrease, p=<0.001).

What question did this study set out to answer?

This study investigates how sodium current influences calcium transients during action potentials in cardiac cells.

July 20, 2010The Journal of PhysiologyOpen Access

Activation of reverse Na⁺-Ca²⁺exchange by the Na⁺current augments the cardiac Ca²⁺transient: evidence from NCX knockout mice

Q: What are the key findings of this study?

In wild-type murine cardiomyocytes, inactivation of INa decreased the Ca2+ transient amplitude by 51.1% (P<0.001), an effect absent in NCX knockout cells.

Q: What question did this study set out to answer?

This study investigates how sodium current influences calcium transients during action potentials in cardiac cells.

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Key result

In wild-type murine cardiomyocytes, inactivation of INa decreased the Ca2+ transient amplitude by 51.1% (P<0.001), an effect absent in NCX knockout cells.

Key Points

This study investigates how sodium current influences calcium transients during action potentials in cardiac cells.
Monitored intracellular Ca2+ in ventricular myocytes from wild-type and NCX knockout mice.
Inactivated I(Na) using a ramp prepulse and tetrodotoxin to assess its impact on Ca2+ transients.
Measured trigger Ca2+ influx under varying conditions, including depleted sarcoplasmic reticulum.
In wild-type myocytes, inactivation of I(Na) decreased the Ca2+ transient amplitude by 51.1% (P < 0.001).
In NCX knockout myocytes, Ca2+ transients were unaffected by I(Na) inactivation.
Trigger Ca2+ influx in wild-type cells decreased by 37.8% with I(Na) inactivation (P < 0.001), with no effect in knockout cells.

Structured PICO

Population

Ventricular myocytes isolated from adult wild-type and NCX knockout mice.

Intervention

Selective inactivation of INa using a ramp prepulse to 45 mV or exposure to 10 µm tetrodotoxin

Comparator

Before inactivation of INa (presence of INa) and NCX KO myocytes

Outcome

Intracellular Ca2+ transient amplitude and maximum release fluxsurrogate

Main Result

Effect estimate: 51.1% decrease

p-value: p=<0.001

INa and reverse NCX modulate Ca2+ release in murine cardiomyocytes by augmenting the pool of Ca2+ that triggers ryanodine receptors, regulating contractility.

Discussion

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Implication

Indicates Na+ current modulates Ca2+ transients via NCX in murine myocytes; leaves open relevance to human cardiac disease.

Cite This Study

Larbig et al. (2010) studied this question. Inactivation of INa vs. Presence of INa / NCX KO cells was evaluated on Ca(2+) transient amplitude (51.1% decrease, p=<0.001). In wild-type murine cardiomyocytes, inactivation of INa decreased the Ca2+ transient amplitude by 51.1% (P<0.001), an effect absent in NCX knockout cells.

synapsesocial.com/papers/6a6a3bbde0327edb0af1ceea https://doi.org/10.1113/jphysiol.2010.187708

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Activation of reverse Na⁺-Ca²⁺exchange by the Na⁺current augments the cardiac Ca²⁺transient: evidence from NCX knockout mice

Key Points

Structured PICO

Main Result

Discussion

Implication

Cite This Study

Activation of reverse Na⁺-Ca²⁺exchange by the Na⁺current augments the cardiac Ca²⁺transient: evidence from NCX knockout mice

Key Points

Structured PICO

Main Result

Discussion

Implication

Cite This Study

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