What question did this study set out to answer?

To determine if vasodilatation is necessary for the increase in blood flow following muscle contraction during exercise.

April 13, 2004The Journal of PhysiologyOpen Access

Vasodilatation is obligatory for contraction‐induced hyperaemia in canine skeletal muscle

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Why the study?

Does intra-arterial potassium infusion prevent contraction-induced hyperaemia in canine skeletal muscle?

Population

Anaesthetized beagle dogs (n=6) and isolated gastrocnemius muscle of mongrel dogs (n=6)

Comparison

Intra-arterial potassium infusion to elevate… vs Control contractions, phenylephrine infusion…

Design

Preclinical

Authors

JHJason J. HamannAbbott Northwestern Hospital JBJohn B. BuckwalterIndiana University – Purdue University Indianapolis PCPhilip S. CliffordVascular Medicine

Discussion

Member takes

Implication

Supports hyperpolarization-mediated vasodilatation over muscle pump in dogs; leaves open mechanism of exercise hyperaemia in humans.

Key Points

To determine if vasodilatation is necessary for the increase in blood flow following muscle contraction during exercise.
Studied response to brief tetanic contraction while infusing potassium to manipulate smooth muscle membrane potential in beagle dogs.
Measured blood flow changes during control and potassium infusion conditions using intra-arterial interventions.
Control contractions increased hindlimb blood flow by 97 +/- 14 ml min(-1), while potassium infusion reduced this to 8 +/- 3 ml min(-1).
Phenylephrine infusion preserved the hyperaemic response, yielding blood flow increases of 89 +/- 23 ml min(-1).
Recoveries after potassium infusion showed no alteration in blood flow response compared to controls (100 +/- 11 ml min(-1)).

Structured PICO

Does intra-arterial potassium infusion prevent contraction-induced hyperaemia in canine skeletal muscle?

Population

Anaesthetized beagle dogs (n=6) and isolated gastrocnemius muscle of mongrel dogs (n=6)

Intervention

Intra-arterial potassium (K+) infusion to elevate [K+]o and clamp smooth muscle membrane potential during a brief tetanic contraction

Comparator

Control contractions (no infusion), phenylephrine infusion (to match baseline blood flow reduction), and recovery contractions

Outcome

Hindlimb blood flow response to contractionsurrogate

The increase in blood flow immediately following a single muscle contraction is due to vasodilatation, likely from smooth muscle hyperpolarization, rather than the muscle pump.

Cite This Study

Hamann et al. (2004) studied this question.

synapsesocial.com/papers/6a74ed69a44b96c1f7dbe760 https://doi.org/10.1113/jphysiol.2004.062836

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Vasodilatation is obligatory for contraction‐induced hyperaemia in canine skeletal muscle

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Vasodilatation is obligatory for contraction‐induced hyperaemia in canine skeletal muscle

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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