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Myogenic responses of mouse isolated perfused renal afferent arterioles: effects of salt intake and reduced renal mass.
- Source :
-
Hypertension (Dallas, Tex. : 1979) [Hypertension] 2010 Apr; Vol. 55 (4), pp. 983-9. Date of Electronic Publication: 2010 Mar 01. - Publication Year :
- 2010
-
Abstract
- Because defects in renal autoregulation may contribute to renal barotrauma in chronic kidney disease, we tested the hypothesis that the myogenic response is diminished by reduced renal mass. Kidneys from 5/6 nephrectomized mice had only a minor increase in the glomerular sclerosis index. The telemetric mean arterial pressure (108+/-10 mm Hg) was unaffected after 3 months of high-salt intake (6% salt in chow) or reduced renal mass. Afferent arterioles from 5/6 nephrectomized mice and sham-operated controls were perfused ex vivo during step changes in pressure from 40 to 134 mm Hg. Afferent arterioles developed a constriction and a linear increase in active wall tension above a perfusion pressure of 36+/-6 mm Hg, without a plateau. The slope of active wall tension versus perfusion pressure defined the myogenic response, which was similar in sham mice fed normal or high-salt diets for 3 months (2.90+/-0.22 versus 3.22+/-0.40 dynes x cm(-1)/mm Hg; P value not significant). The myogenic response was unaffected after 3 days of reduced renal mass on either salt diet (3.39+/-0.61 versus 4.04+/-0.47 dynes x cm(-1)/mm Hg) but was reduced (P<0.05) in afferent arterioles from reduced renal mass groups fed normal and high salt at 3 months (2.10+/-0.28 and 1.35+/-0.21 dynes x cm(-1)/mm Hg). In conclusion, mouse renal afferent arterioles develop a linear increase in myogenic tone around the range of ambient perfusion pressures. This myogenic response is impaired substantially in the mouse model of prolonged reduced renal mass, especially during high salt intake.
- Subjects :
- Albuminuria
Analysis of Variance
Animals
Arterioles drug effects
Arterioles physiology
Blood Pressure physiology
Creatinine blood
Homeostasis physiology
Kidney drug effects
Kidney physiology
Male
Mice
Muscle, Smooth, Vascular
Organ Size
Random Allocation
Sodium Chloride, Dietary pharmacology
Telemetry
Kidney blood supply
Kidney pathology
Vasoconstriction physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1524-4563
- Volume :
- 55
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Hypertension (Dallas, Tex. : 1979)
- Publication Type :
- Academic Journal
- Accession number :
- 20194294
- Full Text :
- https://doi.org/10.1161/HYPERTENSIONAHA.109.149120