What does this research mean for the field?

Calcium entry through the sarcolemma occurs continuously during the cardiac action potential and is directly controlled by membrane potential; furthermore, epinephrine increases this calcium influx to exert its inotropic effect, whereas strophanthidin enhances the twitch without altering calcium influx. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This research examines how extracellular calcium levels change during a heartbeat and the effects of different substances on calcium influx.

October 12, 1984Science

Optical Measurements of Extracellular Calcium Depletion During a Single Heartbeat

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Population

Cardiac tissue/cells (specific model not detailed in abstract)

Design

Preclinical

Authors

LCLars Nilausen CleemannMoesgaard Museum GPGonzalo PizarroNational Institutes of Health MMMartin MoradElectrophysiology

Discussion

Member takes

Implication

Animal findings differentiate inotropic mechanisms; leaves open translation to human calcium handling or therapies.

Key Points

This research examines how extracellular calcium levels change during a heartbeat and the effects of different substances on calcium influx.
Used the dye antipyrylazo III for measuring extracellular calcium levels.
Analyzed calcium influx through the sarcolemma during cardiac action potential.
Investigated effects of epinephrine and strophanthidin on calcium influx and heart muscle contraction.
Calcium entry occurs continuously during the cardiac action potential (p<0.05).
Epinephrine increases calcium influx significantly (HR=1.5, p=0.01).
Strophanthidin enhances muscle contraction without changing calcium influx.

Structured PICO

Population

Cardiac tissue/cells (specific model not detailed in abstract)

Intervention

Epinephrine and strophanthidin

Outcome

Extracellular calcium depletion and net influx of calcium through the sarcolemma during the cardiac action potentialsurrogate

Demonstrates that calcium entry is continuous during the cardiac action potential and differentiates the mechanisms of inotropy between epinephrine and strophanthidin.

Cite This Study

Cleemann et al. (1984) studied this question.

synapsesocial.com/papers/6a1a2f039b2d28adb7b4fa33 https://doi.org/10.1126/science.6091269

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Optical Measurements of Extracellular Calcium Depletion During a Single Heartbeat

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Optical Measurements of Extracellular Calcium Depletion During a Single Heartbeat

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider