What is the clinical evidence from this study?

Study design: Other. Intervention: Species differences (hamster, guinea-pig, human, rat). Primary outcome: Na(+)-Ca2+ exchanger activity (INa-Ca magnitude and kinetics).

What question did this study set out to answer?

This research evaluates how the Na(+)-Ca2+ exchanger's activity varies among species in cardiac myocytes, particularly in response to calcium release.

November 1, 1995The Journal of PhysiologyOpen Access

Species differences in the activity of the Na(+)‐Ca2+ exchanger in mammalian cardiac myocytes.

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Key result

The magnitude of Na+-Ca2+ exchange currents was largest in hamster myocytes and smallest in rat, with guinea-pig and human myocytes having intermediate values (ratio 4:2:1.5:1).

Population

Isolated cardiac myocytes from rat, guinea-pig, hamster ventricles, and human atria

Comparison

Rapid application of caffeine or Ca2+ current to… vs Comparison across species

Design

Preclinical

Authors

JSJames S.K. ShamJohns Hopkins University SHStéphane HatemElectrophysiology MMMartin MoradElectrophysiology

Discussion

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Implication

Species differences in Na-Ca exchanger activity across models warrant caution extrapolating to humans; leaves open need for targeted human validation.

Key Points

This research evaluates how the Na(+)-Ca2+ exchanger's activity varies among species in cardiac myocytes, particularly in response to calcium release.
Isolated myocytes were studied from rat, guinea-pig, hamster, and human hearts.
Fluorescence measurements using fura-2 were combined with whole-cell patch-clamp for electrical and calcium signaling analysis.
Caffeine and calcium currents were used to induce and measure Na(+)-Ca2+ exchange currents.
INa-Ca was largest in hamster (4), smallest in rat (1), with guinea-pig (2) and human (1.5) showing intermediate exchanger current densities.
Ca2+ removal rates followed the same order: hamster > guinea-pig > human ≥ rat.
Differences were observed in the kinetics of INa-Ca and Ca2+ transients, notably faster in hamster myocytes.

Structured PICO

Population

Isolated cardiac myocytes from rat, guinea-pig, hamster ventricles, and human atria

Exposure

Rapid application of caffeine or Ca2+ current to induce Ca2+ release from sarcoplasmic reticulum

Comparator

Comparison across species (rat, guinea-pig, hamster, human)

Outcome

Activity of the Na(+)-Ca2+ exchanger (magnitude of INa-Ca, rates of Ca2+ removal, and kinetics)surrogate

There are significant species differences in the Na(+)-Ca2+ exchanger activity of cardiac myocytes, which has implications for the choice of animal models in cardiac electrophysiology research.

Cite This Study

Sham et al. (1995) studied this question. Species differences (hamster, guinea-pig, human, rat) was evaluated on Na(+)-Ca2+ exchanger activity (INa-Ca magnitude and kinetics). The magnitude of Na+-Ca2+ exchange currents was largest in hamster myocytes and smallest in rat, with guinea-pig and human myocytes having intermediate values (ratio 4:2:1.5:1).

synapsesocial.com/papers/6a6d481ce36a167817dff4dd https://doi.org/10.1113/jphysiol.1995.sp020995

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Implication

Species differences in Na-Ca exchanger activity across models warrant caution extrapolating to humans; leaves open need for targeted human validation.

Species differences in the activity of the Na(+)‐Ca2+ exchanger in mammalian cardiac myocytes.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Species differences in the activity of the Na(+)‐Ca2+ exchanger in mammalian cardiac myocytes.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

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