What question did this study set out to answer?

This study aims to explore how norepinephrine affects coronary circulation and left ventricular dynamics in conscious dogs.

June 1, 1974Circulation Research

Effects of Norepinephrine on Coronary Circulation and Left Ventricular Dynamics in the Conscious Dog

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Why the study?

Does norepinephrine alter coronary circulation and left ventricular dynamics in conscious dogs?

Key Points

This study aims to explore how norepinephrine affects coronary circulation and left ventricular dynamics in conscious dogs.
Conscious dogs received intravenous norepinephrine at doses of 0.1 and 1.0 µg/kg.
Coronary blood flow, pressure measurements, and left ventricular dynamics were assessed.
Beta and alpha-receptor blockades were applied to evaluate their effects on responses.
Norepinephrine caused an initial reduction in coronary vascular resistance followed by a sustained increase (+0.55 ± 0.07 mm Hg/ml min -1 ).
Mean arterial blood pressure increased significantly (+67 ± 7 mm Hg) along with left ventricular pressures and diameter.
Beta-receptor blockade reduced norepinephrine's inotropic effects and modified vascular responses.

Structured PICO

Does norepinephrine alter coronary circulation and left ventricular dynamics in conscious dogs?

Population

Conscious dogs (and anesthetized, open-chest dogs)

Intervention

Norepinephrine (0.1 and 1.0 µg/kg, iv)

Comparator

Baseline, beta-receptor blockade, alpha-receptor blockade, and anesthetized state

Outcome

Coronary blood flow and resistance, left ventricular pressure and diameter, dP/dt, (dP/dt)/P, and velocity of myocardial fiber shorteningsurrogate

Norepinephrine exerts an important alpha-receptor-mediated coronary vasoconstrictor effect in conscious dogs that is sufficiently intense to counteract metabolic vasodilatation, an effect not seen in anesthetized dogs.

Discussion

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Implication

Norepinephrine's alpha-mediated coronary vasoconstriction in conscious dogs cautions against anesthetized model reliance; leaves open human translation.

Cite This Study

Vatner et al. (1974) studied this question.

synapsesocial.com/papers/6a20abaa920e38fa09f9e336 https://doi.org/10.1161/01.res.34.6.812

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Implication

Norepinephrine's alpha-mediated coronary vasoconstriction in conscious dogs cautions against anesthetized model reliance; leaves open human translation.

Effects of Norepinephrine on Coronary Circulation and Left Ventricular Dynamics in the Conscious Dog

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Effects of Norepinephrine on Coronary Circulation and Left Ventricular Dynamics in the Conscious Dog

Key Points

Structured PICO

Discussion

Implication

Cite This Study

Also Consider

Also Consider