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Carotid sinus baroreceptor sensitivity in experimental heart failure
1Department of Physiology and Biophysics, University of Nebraska College of Medicine, Omaha 68105.
Circulation
|June 1, 1990
Summary
Heart failure significantly reduces carotid sinus baroreceptor sensitivity in dogs. Ouabain partially restored this function, suggesting a potential therapeutic target for baroreceptor dysfunction in heart failure.
Area of Science:
- Cardiovascular Physiology
- Neuroscience
- Baroreceptor Function
Background:
- Heart failure is associated with altered autonomic nervous system function.
- Carotid sinus baroreceptors play a crucial role in regulating blood pressure.
- The impact of heart failure on carotid sinus baroreceptor sensitivity is not fully understood.
Purpose of the Study:
- To compare carotid sinus baroreceptor sensitivity between normal and heart failure dogs.
- To investigate the effect of ouabain on baroreceptor function in heart failure.
Main Methods:
- Recorded single-unit carotid sinus baroreceptor activity in anesthetized normal and pacing-induced heart failure dogs.
- Measured carotid sinus pressure (CSP) and diameter.
- Constructed CSP-discharge and CSP-diameter curves.
- Administered ouabain to the carotid sinus in heart failure dogs.
Main Results:
- Heart failure dogs showed significantly decreased peak baroreceptor discharge and elevated threshold pressure compared to normal dogs.
- The slope of the CSP-discharge curve was significantly lower in heart failure dogs.
- Ouabain administration in heart failure dogs significantly decreased threshold pressure and increased peak discharge and curve slope, without affecting diameter.
Conclusions:
- Pacing-induced heart failure significantly impairs carotid sinus baroreceptor sensitivity.
- Ouabain partially reverses baroreceptor dysfunction in heart failure, suggesting a role for endogenous digitalis-like factors or altered receptor sensitivity.