What question did this study set out to answer?

Investigate the functional effects of overexpressing the cardiac sodium-calcium exchanger (NCX1) on contractility and sarcoplasmic reticulum calcium regulation in adult rat ventricular myocytes.

November 1, 2001AJP Heart and Circulatory Physiology

Overexpression of Na⁺/Ca²⁺exchanger alters contractility and SR Ca²⁺content in adult rat myocytes

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Investigate the functional effects of overexpressing the cardiac sodium-calcium exchanger (NCX1) on contractility and sarcoplasmic reticulum calcium regulation in adult rat ventricular myocytes.
Cultured adult rat myocytes were maintained under continuous electrical field stimulation for 48 hours.
Cells were infected with adenovirus vectors expressing green fluorescent protein (GFP) alone or co-expressing GFP and NCX1.
Assessed contractility, intracellular calcium ([Ca2+]i) transients, sarcoplasmic reticulum (SR) Ca2+ content under varying extracellular Ca2+ levels, and protein expression via Western blot.
Adenoviral infection achieved >95% efficiency, yielding a 3-fold increase in NCX1 protein abundance (P <= 0.02) without altering SR Ca2+-ATPase or calsequestrin levels.
NCX1-overexpressing myocytes exhibited lower resting and diastolic [Ca2+]i, along with altered contraction and [Ca2+]i transient amplitudes compared to GFP controls.
SR Ca2+ content depended on extracellular Ca2+ concentration ([Ca2+]o), decreasing at low [Ca2+]o and increasing at high [Ca2+]o, which produced larger twitches and Ca2+ transients.

Structured PICO

Population

Adult rat myocytes in primary culture

Intervention

Infection by adenovirus expressing both green fluorescent protein (GFP) and Na+/Ca2+ exchanger (NCX1) to overexpress NCX1

Comparator

Myocytes infected by adenovirus expressing GFP alone

Outcome

Contraction amplitude, intracellular Ca2+ concentration ([Ca2+]i) transients, resting and diastolic [Ca2+]i, and sarcoplasmic reticulum (SR) Ca2+ contentsurrogate

Overexpression of NCX1 in adult rat myocytes alters contractility and SR Ca2+ content by enhancing both forward and reverse NCX1 function depending on extracellular calcium levels.

Discussion

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Implication

NCX1 overexpression alters adult myocyte Ca2+ handling; leaves open its therapeutic targeting in heart failure pending in vivo validation.

Cite This Study

Zhang et al. (2001) studied this question.

synapsesocial.com/papers/6a7c34438add427333df8341 https://doi.org/10.1152/ajpheart.2001.281.5.h2079

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Implication

NCX1 overexpression alters adult myocyte Ca2+ handling; leaves open its therapeutic targeting in heart failure pending in vivo validation.

Overexpression of Na⁺/Ca²⁺exchanger alters contractility and SR Ca²⁺content in adult rat myocytes

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Overexpression of Na⁺/Ca²⁺exchanger alters contractility and SR Ca²⁺content in adult rat myocytes

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider