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Effect of experimental heart failure on peripheral sympathetic vasoconstriction
J R Wilson1, W Matthai, V Lanoce
1Department of Medicine, University of Pennsylvania, Philadelphia 19104.
The American Journal of Physiology
|April 1, 1988
Summary
Heart failure impairs sympathetic vasoconstriction in dogs, particularly at higher nerve stimulation rates. This suggests reduced neurotransmitter release may worsen heart failure severity.
Area of Science:
- Cardiovascular Physiology
- Neuroscience
- Heart Failure Research
Background:
- Peripheral sympathetic vasoconstriction is crucial for regulating blood pressure.
- Chronic heart failure is associated with complex circulatory dysfunctions.
- The impact of heart failure on sympathetic vasoconstrictive capacity requires further elucidation.
Purpose of the Study:
- To determine if chronic heart failure impairs peripheral sympathetic vasoconstriction.
- To investigate the dose-response relationship of sympathetic stimulation on hindlimb vasculature in heart failure.
- To assess the role of neurotransmitter release in impaired vasoconstriction.
Main Methods:
- Chronic heart failure was induced in dogs via rapid ventricular pacing.
- Hindlimb vascular responses to lumbar chain nerve stimulation (0.5-20 Hz) were measured.
- Vascular responses to exogenous norepinephrine administration were evaluated.
Main Results:
- Sympathetic vasoconstriction was comparable between normal and heart failure dogs at low stimulation rates (0.5-3 Hz).
- Significantly attenuated hindlimb vascular responses were observed in heart failure dogs at higher stimulation rates (5-20 Hz).
- Responses to norepinephrine were unaltered, suggesting a pre-junctional defect.
Conclusions:
- Chronic heart failure leads to impaired sympathetic vasoconstriction.
- Reduced neurotransmitter release is the likely mechanism behind this impairment.
- Impaired vasoconstriction may hinder circulatory compensation in heart failure, potentially exacerbating the condition.