High-NaCl diet impairs dynamic renal blood flow autoregulation in rats with adenine-induced chronic renal failure.
This study examined the effects of 2 wk of high-NaCl diet on kidney function and dynamic renal blood flow autoregulation (RBFA) in rats with adenine-induced chronic renal failure (ACRF). Male Sprague-Dawley rats received either chow containing adenine or were pair-fed an identical diet without adenine (controls). After 10 wk, rats were randomized to either remain on the same diet (0.6% NaCl) or to be switched to high 4% NaCl chow. Two weeks after randomization, renal clearance experiments were performed under isoflurane anesthesia and dynamic RBFA, baroreflex sensitivity (BRS), systolic arterial pressure variability (SAPV), and heart rate variability were assessed by spectral analytical techniques. Rats with ACRF showed marked reductions in glomerular filtration rate and renal blood flow (RBF), whereas mean arterial pressure and SAPV were significantly elevated. In addition, spontaneous BRS was reduced by ∼50% in ACRF animals. High-NaCl diet significantly increased transfer function fractional gain values between arterial pressure and RBF in the frequency range of the myogenic response (0.06-0.09 Hz) only in ACRF animals (0.3 ± 4.0 vs. -4.4 ± 3.8 dB; P < 0.05). Similarly, a high-NaCl diet significantly increased SAPV in the low-frequency range only in ACRF animals. To conclude, a 2-wk period of a high-NaCl diet in ACRF rats significantly impaired dynamic RBFA in the frequency range of the myogenic response and increased SAPV in the low-frequency range. These abnormalities may increase the susceptibility to hypertensive end-organ injury and progressive renal failure by facilitating pressure transmission to the microvasculature.
Department of Molecular and Clinical Medicine/Nephrology, Institute of Medicine, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden;
Aso
A
Saeed
Gerald F
GF
DiBona
Elisabeth
E
Grimberg
Lisa
L
Nguy
Minne Line Nedergaard
ML
Mikkelsen
Niels
N
Marcussen
Gregor
G
Guron
D000225:Adenine / Q000494:pharmacology*; D000818:Animals; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005919:Glomerular Filtration Rate / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006706:Homeostasis / Q000502:physiology*; D006977:Hypertension, Renal / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation / Q000502:physiology*; D017673:Sodium Chloride, Dietary / Q000494:pharmacology*
D017673:Sodium Chloride, Dietary; D000225:Adenine
adenine; arterial pressure variability; baroreflex sensitivity; chronic renal failure; renal blood flow autoregulation