What question did this study set out to answer?

To determine whether energy produced by glycolytic versus oxidative metabolic pathways is selectively channeled to distinct cellular processes in the myocardium.

February 1, 1985Journal of Clinical InvestigationOpen Access

Functional compartmentation of glycolytic versus oxidative metabolism in isolated rabbit heart.

Q: What does this research mean for the field?

In the heart, energy derived from glycolysis is preferentially used to support sarcolemmal function, whereas oxidatively derived energy preferentially supports contractile function. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

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Population

Isolated arterially perfused rabbit interventricular septa

Comparison

Inhibition of oxidative metabolism (hypoxia… vs Comparison between inhibition of oxidative…

Design

Preclinical

Follow-up

10 minutes

Authors

JWJames N. WeissElectrophysiology BHB HiltbrandClinique du Grand Large

Discussion

Member takes

Implication

Should not yet inform metabolic interventions in patients; leaves open compartment-specific energy utilization as a therapeutic target in human myocardium.

Key Points

To determine whether energy produced by glycolytic versus oxidative metabolic pathways is selectively channeled to distinct cellular processes in the myocardium.
Monitored contractile tension, intracellular potential, extracellular potassium ([K+]o), and extracellular pH using triple-barrel microelectrodes in isolated, arterially perfused rabbit interventricular septa.
Treated septal preparations with hypoxia, oxidative phosphorylation inhibitors (10⁻⁵ M dinitrophenol, 10⁻³ M sodium azide), or a glycolytic inhibitor (10⁻³ M iodoacetate [IAA]).
Measured myocardial contents of high-energy phosphates, lactate, and glycogen across all experimental conditions.
Oxidative inhibition by hypoxia, dinitrophenol, and sodium azide significantly suppressed contractile tension (by 73 ± 5%, 65 ± 8%, and 50 ± 14%, respectively) while causing modest [K+]o increases (0.8 ± 0.4, 0.5 ± 0.25, and 0.4 ± 0.2 mM).
Glycolytic inhibition with IAA caused markedly less tension suppression (28 ± 24%) but induced substantial [K+]o accumulation (1.8 ± 1.1 mM), differing significantly from the oxidative interventions.
Action potential duration shortening was not significantly different among interventions, and total high-energy phosphate stores remained preserved under all conditions except hypoxia.

Structured PICO

Population

Isolated arterially perfused rabbit interventricular septa

Intervention

Inhibition of oxidative metabolism (hypoxia, dinitrophenol 10(-5)M, or Na-azide 10(-3)M) or inhibition of glycolysis (iodoacetate 10(-3)M)

Comparator

Comparison between inhibition of oxidative metabolism and inhibition of glycolysis

Outcome

Tension, intracellular potential, extracellular [K+] and pH, and myocardial content of high energy phosphates, lactate, and glycogensurrogate

In the isolated rabbit heart, energy from glycolysis preferentially supports sarcolemmal function (preventing K+ loss), whereas oxidatively derived energy preferentially supports contractile function.

Cite This Study

Weiss et al. (1985) studied this question.

synapsesocial.com/papers/6a1b7f3c39ea7417dc42e830 https://doi.org/10.1172/jci111718

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Implication

Should not yet inform metabolic interventions in patients; leaves open compartment-specific energy utilization as a therapeutic target in human myocardium.

Functional compartmentation of glycolytic versus oxidative metabolism in isolated rabbit heart.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Functional compartmentation of glycolytic versus oxidative metabolism in isolated rabbit heart.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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