What is the clinical evidence from this study?

Study design: Other. Population: Isolated rat heart. Intervention: Isoproterenol infusion or hypoxia vs. Preinfusion/normoxic levels. Primary outcome: Cytosolic energy metabolism, adenosine efflux, and coronary flow (p=<0.001).

What question did this study set out to answer?

To examine the temporal and quantitative relations between cytosolic energy metabolism, adenosine release, and coronary blood flow during adrenergic stimulation and hypoxia.

March 1, 1990AJP Heart and Circulatory Physiology

Adenosine formation and energy metabolism: a 31P-NMR study in isolated rat heart

Q: What are the key findings of this study?

In isolated rat hearts, isoproterenol infusion and hypoxia increased coronary flow and adenosine release while decreasing cytosolic phosphorylation potential (P<0.001).

Q: What question did this study set out to answer?

To examine the temporal and quantitative relations between cytosolic energy metabolism, adenosine release, and coronary blood flow during adrenergic stimulation and hypoxia.

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Key result

In isolated rat hearts, isoproterenol infusion and hypoxia increased coronary flow and adenosine release while decreasing cytosolic phosphorylation potential (P<0.001).

Population

Isolated isovolumic rat heart

Comparison

Isoproterenol infusion or hypoxia for 10 min… vs Preinfusion or normoxic baseline levels

Design

Preclinical

Follow-up

10 min

Authors

JHJohn P. HeadrickGriffith University RWRoger J. WillisGriffith University

Discussion

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Implication

Does not support clinical adenosine modulation; leaves open translation of rat heart findings to human coronary physiology.

Key Points

To examine the temporal and quantitative relations between cytosolic energy metabolism, adenosine release, and coronary blood flow during adrenergic stimulation and hypoxia.
Isolated isovolumic rat hearts were subjected to 10 minutes of either 60 nM isoproterenol infusion or 5% O2 hypoxia.
Myocardial cytosolic phosphorylation potential ([ATP]/[ADP][Pi]) and free [AMP] were monitored in real time using 31P-nuclear magnetic resonance spectroscopy while coronary effluent was assayed for adenosine.
Adenosine deaminase was infused to evaluate the physiological consequences of endogenous adenosine degradation on vascular and mechanical responses.
Isoproterenol and hypoxia reduced [ATP]/[ADP][Pi] to <25% of baseline and increased coronary flow to ~170% and 190%, respectively (P < 0.001).
Venous adenosine efflux increased >10-fold and exhibited an inverse linear correlation with log[ATP]/[ADP][Pi] as well as positive linear correlations with cytosolic [AMP] and coronary flow.
Adenosine deaminase reduced vasodilation by ~30% during isoproterenol and ~40% during hypoxia (P < 0.001), while worsening cytosolic energy depletion (P < 0.05).

Structured PICO

Population

Isolated isovolumic rat hearts subjected to isoproterenol infusion or hypoxia.

Intervention

Isoproterenol (ISO) infusion (60 nM) or hypoxia (5% O2) for 10 min, with or without adenosine deaminase (ADA) treatment

Comparator

Preinfusion or normoxic baseline levels

Outcome

Temporal and quantitative relations between cytosolic energy metabolism ([ATP]/[ADP][Pi]), adenosine efflux, and coronary flowsurrogate

Main Result

p-value: p=<0.001

Endogenous adenosine mediates metabolic vasodilation and modulates catecholamine responses in isolated rat hearts during hypoxia and inotropic stimulation.

Cite This Study

Headrick et al. (1990) studied Isolated rat heart. Isoproterenol infusion or hypoxia vs. Preinfusion/normoxic levels was evaluated on Cytosolic energy metabolism, adenosine efflux, and coronary flow (p=<0.001). In isolated rat hearts, isoproterenol infusion and hypoxia increased coronary flow and adenosine release while decreasing cytosolic phosphorylation potential (P<0.001).

synapsesocial.com/papers/6a9dd631d69bd27bfcf9d8d1 https://doi.org/10.1152/ajpheart.1990.258.3.h617

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Adenosine formation and energy metabolism: a 31P-NMR study in isolated rat heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Adenosine formation and energy metabolism: a 31P-NMR study in isolated rat heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Also Consider

Also Consider