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Renal mechanoreceptor dysfunction: an intermediate phenotype in spontaneously hypertensive rats
G F DiBona1, S Y Jones, U C Kopp
1Departments of Internal Medicine and Physiology, University of Iowa College of Medicine, and the Veterans Administration Medical Center, Iowa City 52242, USA. gerald-dibona@uiowa.edu
Hypertension (Dallas, Tex. : 1979)
|February 4, 1999
Summary
Decreased responsiveness in kidney mechanosensitive neurons is linked to hypertension in rats. This finding suggests a key intermediate phenotype contributing to high blood pressure and sodium retention in spontaneously hypertensive rats.
Area of Science:
- Nephrology
- Cardiovascular Physiology
- Neuroscience
Background:
- Spontaneously hypertensive rats (SHR) exhibit increased renal sympathetic nerve activity and sodium retention.
- The role of renal mechanosensitive neurons in hypertension development is not fully understood.
- Renal mechanoreceptor responsiveness may represent an intermediate phenotype in hypertension.
Purpose of the Study:
- To test the hypothesis that decreased responsiveness of renal mechanosensitive neurons is an intermediate phenotype in SHR.
- To investigate the relationship between renal mechanoreceptor responsiveness and hypertension.
- To determine if decreased renal mechanosensor function contributes to increased sympathetic activity and sodium retention.
Main Methods:
- A backcross population of rats (borderline hypertensive rats x Wistar-Kyoto rats) was used.
- Rats were fed an 8% NaCl diet for 12 weeks.
- Mean arterial pressure and afferent renal nerve activity were measured in response to increased ureteral pressure.
Main Results:
- Mean arterial pressure ranged from 110 to 212 mm Hg.
- Hypertension was inversely correlated with the increase in afferent renal nerve activity during elevated ureteral pressure.
- Decreased responsiveness of renal mechanosensitive neurons cosegregated with hypertension.
Conclusions:
- Decreased responsiveness of renal mechanosensitive neurons is an intermediate phenotype in spontaneously hypertensive rats.
- This altered mechanosensor function contributes to increased renal sympathetic nerve activity and sodium retention.
- Understanding this intermediate phenotype provides insights into the complex mechanisms of hypertension.