What question did this study set out to answer?

To develop and evaluate a model characterizing calcium uptake and release kinetics in the intact sarcoplasmic reticulum of adult mammalian ventricular cardiomyocytes.

September 1, 1990Journal of Biological ChemistryOpen Access

Calcium accumulation and release by the sarcoplasmic reticulum of digitonin-lysed adult mammalian ventricular cardiomyocytes.

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Population

Digitonin-lysed adult mammalian ventricular cardiomyocytes

Comparison

Various media conditions and pharmacological… vs Control conditions without inhibitors or…

Design

Preclinical

Authors

DWD K WimsattDepartment of Physiological Sciences CHCorinne M. HohlUniversity of British Columbia GBGerald P. BrierleyKettering Foundation

Discussion

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Implication

This intact-cell model extends SR Ca2+ uptake characterization to hyperthyroid and HF states; leaves open human relevance.

Key Points

To develop and evaluate a model characterizing calcium uptake and release kinetics in the intact sarcoplasmic reticulum of adult mammalian ventricular cardiomyocytes.
Permeabilized adult rat and canine ventricular cardiomyocytes using digitonin to evaluate 45Ca2+ uptake across various free Ca2+ concentrations, buffer ions, and phosphocreatine conditions.
Inhibited calcium-induced calcium release channels using ruthenium red and procaine, and stimulated release using ryanodine across normal, hyperthyroid, and heart failure-prone models.
Under calcium efflux inhibition with ruthenium red (30 µM) and procaine (10 mM), SR 45Ca2+ uptake was saturable with a Vmax of 160 ± 5 nmol·min⁻¹·mg⁻¹ and K0.5 of 500 nM free Ca2+.
Vmax for 45Ca2+ uptake increased by 20% in hyperthyroid rat myocytes but was depressed by 30% in myocytes from heart failure-prone rats.
Ryanodine caused a concentration-dependent reduction in net uptake at pCa 6.3 (K0.5 = 1 µM), an effect completely reversed by co-treatment with ruthenium red and procaine.

Structured PICO

Population

Digitonin-lysed adult mammalian ventricular cardiomyocytes (from normal rats, hyperthyroid rats, heart failure-prone rats, and canines)

Intervention

Various media conditions (Na+-based, K+-based) and pharmacological agents (ruthenium red, procaine, ryanodine)

Comparator

Control conditions without inhibitors or different media

Outcome

Sarcoplasmic reticulum 45Ca2+ uptake kinetics (Vmax, K0.5)surrogate

This model characterizes intact cardiac sarcoplasmic reticulum calcium handling, demonstrating altered uptake kinetics in hyperthyroid and heart failure-prone models.

Cite This Study

Wimsatt et al. (1990) studied this question.

synapsesocial.com/papers/6a829067129689dedc133196 https://doi.org/10.1016/s0021-9258(18)77192-5

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Calcium accumulation and release by the sarcoplasmic reticulum of digitonin-lysed adult mammalian ventricular cardiomyocytes.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Calcium accumulation and release by the sarcoplasmic reticulum of digitonin-lysed adult mammalian ventricular cardiomyocytes.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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