What question did this study set out to answer?

To determine how arterial smooth muscle activation induced by norepinephrine alters the transmural pressure dependence of characteristic impedance in conduit arteries.

August 1, 1976American Journal of Physiology-Legacy Content

Effects of norepinephrine on mechanics of arteries in vitro

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Why the study?

Does norepinephrine activation of smooth muscle affect the pressure dependence of arterial wall characteristic impedance in isolated canine arteries?

Population

Isolated segments of canine iliac and carotid arteries

Comparison

Norepinephrine in concentrations of 0.5 and 5… vs Absence of smooth muscle tone (before activation)

Design

Preclinical

Authors

RCR. H. CoxTexas Tech University

Discussion

Member takes

Implication

Smooth muscle activation may stabilize arterial impedance near physiological pressures in canine vessels; leaves open translation to human hemodynamics.

Key Points

To determine how arterial smooth muscle activation induced by norepinephrine alters the transmural pressure dependence of characteristic impedance in conduit arteries.
Tested isolated canine iliac and carotid artery segments in vitro across varying transmural pressures.
Measured external vessel diameters before and after smooth muscle activation using norepinephrine at 0.5 and 5 µg/ml.
Calculated arterial wall characteristic impedance across the tested pressure ranges under passive and activated conditions.
In the absence of smooth muscle tone, characteristic impedance in both carotid and iliac arteries increased monotonically with rising transmural pressure.
Activation with 5 µg/ml norepinephrine created a distinct characteristic impedance minimum around 125 mmHg, while 0.5 µg/ml produced a similar but broader minimum across pressures.

Structured PICO

Does norepinephrine activation of smooth muscle affect the pressure dependence of arterial wall characteristic impedance in isolated canine arteries?

Population

Isolated segments of canine iliac and carotid arteries

Intervention

Norepinephrine (NE) in concentrations of 0.5 and 5 mug/ml

Comparator

Absence of smooth muscle tone (before activation)

Outcome

Pressure dependence of arterial wall characteristic impedance (Z0)surrogate

Smooth muscle activation by norepinephrine creates a minimum in characteristic impedance around physiological pressures, suggesting that the constancy of vascular impedance with pressure changes is due to tonic smooth muscle activation.

Cite This Study

R. H. Cox (1976) studied this question.

synapsesocial.com/papers/6a6fb87ace524a4339c396fb https://doi.org/10.1152/ajplegacy.1976.231.2.420

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Implication

Smooth muscle activation may stabilize arterial impedance near physiological pressures in canine vessels; leaves open translation to human hemodynamics.

Effects of norepinephrine on mechanics of arteries in vitro

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Effects of norepinephrine on mechanics of arteries in vitro

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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Also Consider