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A perspective on the muscle reflex: implications for congestive heart failure
Lawrence I Sinoway1, Jianhua Li
1Division of Cardiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA. lsinoway@psu.edu
Journal of Applied Physiology (Bethesda, Md. : 1985)
|July 23, 2005
Summary
The exercise pressor reflex, crucial for blood pressure regulation during exercise, is altered in heart failure. Specifically, the metabolic reflex is weakened, while the mechanical reflex intensifies, impacting kidney function.
Area of Science:
- Cardiovascular Physiology
- Exercise Physiology
- Neuroscience
Background:
- The exercise pressor reflex regulates blood pressure during physical activity.
- Muscle afferents, stimulated by metabolic and mechanical factors, are key components of this reflex.
- Understanding these mechanisms is vital for managing cardiovascular diseases.
Purpose of the Study:
- To review the exercise pressor reflex in both healthy individuals and those with disease.
- To elucidate the roles of ATP and lactic acid in stimulating muscle afferents.
- To examine alterations in this reflex within the context of heart failure.
Main Methods:
- Review of existing literature on the exercise pressor reflex.
- Discussion of the roles of specific receptors: purinergic receptors (P2X), vanilloid receptor 1 (TRPV1), and acid-sensing ion channels (ASICs).
- Analysis of data comparing reflex responses in health versus heart failure.
Main Results:
- Metabolic and mechanical stimulation of muscle afferents are discussed.
- ATP and lactic acid's roles in afferent stimulation and sensitization are examined.
- Evidence suggests an attenuated metaboreflex and accentuated mechanoreflex in heart failure.
- The muscle mechanoreflex's role in renal vasoconstriction is described.
Conclusions:
- The exercise pressor reflex exhibits significant alterations in heart failure.
- These changes, particularly the heightened mechanoreflex, may contribute to cardiovascular dysfunction, including renal vasoconstriction.
- Further research into these altered reflexes could inform therapeutic strategies.