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Enhanced peripheral chemoreflex function in conscious rabbits with pacing-induced heart failure
1Department of Physiology and Biophysics, University of Nebraska College of Medicine, Omaha, Nebraska 68198-4575, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|April 8, 1999
Summary
In chronic heart failure (CHF), the peripheral chemoreflex is enhanced, leading to increased sympathetic nerve activity. Central chemoreflex function remains unchanged in this condition.
Area of Science:
- Cardiovascular Physiology
- Neuroscience
- Renal Physiology
Background:
- Chronic heart failure (CHF) is associated with sympathetic activation.
- The role of chemoreflexes in mediating sympathetic activation in CHF is not fully understood.
Purpose of the Study:
- To investigate alterations in peripheral and central chemoreflex function in a rabbit model of chronic heart failure (CHF).
- To determine if altered chemoreflex function contributes to sympathetic activation in CHF.
Main Methods:
- A rabbit model of pacing-induced CHF was utilized.
- Measurements included renal sympathetic nerve activity (RSNA) and minute ventilation (MV) in response to peripheral chemoreceptor stimulation.
- Central chemoreflex function was assessed using hyperoxic/hypercapnic challenges.
Main Results:
- Baseline RSNA was significantly higher in CHF rabbits compared to sham rabbits.
- CHF rabbits exhibited enhanced RSNA and MV responses to peripheral chemoreceptor stimulation.
- Peripheral chemoreceptor inhibition reduced RSNA in CHF rabbits, but not in sham rabbits.
- Central chemoreflex function did not differ between CHF and sham rabbits.
Conclusions:
- The study suggests an enhancement of peripheral chemoreflex function in pacing-induced CHF.
- This enhanced peripheral chemoreflex contributes to sympathetic overactivity observed in the CHF state.