(Hypertension. 2001;38:147.)
© 2001 American Heart Association, Inc.
Scientific Contributions |
Renal Blood Flow Dynamics and Arterial Pressure Lability in the Conscious Rat
From the Département de Physiologie et Pharmacologie Clinique, CNRS UMR 5014, Institut Fédératif de Recherche Cardio-Vasculaire No. 39, Université Claude Bernard, Lyon, France.
Correspondence to C. Julien, CNRS UMR 5014, Faculté de Pharmacie, 8 av. Rockefeller, 69373 Lyon, France. E-mail julien{at}univ-lyon1.fr
Abstract—— It is not known whether renal blood flow (RBF) is still autoregulated when the kidney is exposed to large transient blood pressure (BP) fluctuations such as those occurring spontaneously in conscious sinoaortic baroreceptor-denervated (SAD) rats. In this study, BP and RBF were simultaneously recorded in 8 SAD rats (2 weeks before study) and 8 baroreceptor-intact rats during 
3 hours of spontaneous activity. The kidney used for RBF recordings was denervated to prevent the interference of changes in renal sympathetic tone with autoregulatory mechanisms. In intact rats, RBF variability (coefficient of variation 9.1±0.8%) was larger (P<0.02) than BP variability (5.9±0.2%). This was mainly because of slow changes in RBF that were unrelated to BP and also to a prominent oscillation of RBF of 0.25-Hz frequency. Autoregulatory patterns were identified at frequencies <0.1 Hz and provided a modest attenuation of BP fluctuations. In SAD rats, RBF variability (12.4±1.6%) was lower (P<0.02) than BP variability (18.2±1.1%). Autoregulation powerfully attenuated BP changes <0.1 Hz (normalized transfer gain 0.21±0.02 in the 0.0015- to 0.01-Hz frequency range) but at the expense of an oscillation located at 0.05 Hz that possibly reflected the operation of the tubuloglomerular feedback. Large transient hypertensive episodes were not translated into RBF changes in SAD rats. We conclude that autoregulatory mechanisms have an ample capacity to protect the kidney against spontaneous BP fluctuations in the conscious rat. This capacity is not fully used under normal conditions of low BP variability.
Key Words: autoregulation • blood pressure • rats • denervation
This article has been cited by other articles:
 |
|
 |
|
  W. A. Cupples and B. Braam Assessment of renal autoregulation Am J Physiol Renal Physiol, April 1, 2007; 292(4): F1105 - F1123. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Just Mechanisms of renal blood flow autoregulation: dynamics and contributions Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R1 - R17. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Emonnot, C. Bakhos, B. Chapuis, V. Orea, C. Barres, and C. Julien Role of purinergic cotransmission in the sympathetic control of arterial pressure variability in conscious rats Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2006; 291(3): R736 - R741. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Loutzenhiser, K. Griffin, G. Williamson, and A. Bidani Renal autoregulation: new perspectives regarding the protective and regulatory roles of the underlying mechanisms Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2006; 290(5): R1153 - R1167. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Abu-Amarah, A. K. Bidani, R. Hacioglu, G. A. Williamson, and K. A. Griffin Differential effects of salt on renal hemodynamics and potential pressure transmission in stroke-prone and stroke-resistant spontaneously hypertensive rats Am J Physiol Renal Physiol, August 1, 2005; 289(2): F305 - F313. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. W. Kurtz, K. A. Griffin, A. K. Bidani, R. L. Davisson, and J. E. Hall Recommendations for Blood Pressure Measurement in Humans and Experimental Animals: Part 2: Blood Pressure Measurement in Experimental Animals. A Statement for Professionals From the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research Arterioscler. Thromb. Vasc. Biol., March 1, 2005; 25(3): e22 - e33. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. W. Kurtz, K. A. Griffin, A. K. Bidani, R. L. Davisson, and J. E. Hall Recommendations for Blood Pressure Measurement in Humans and Experimental Animals: Part 2: Blood Pressure Measurement in Experimental Animals: A Statement for Professionals From the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research Hypertension, February 1, 2005; 45(2): 299 - 310. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. W. Hamner, M. A. Cohen, S. Mukai, L. A. Lipsitz, and J. A. Taylor Spectral indices of human cerebral blood flow control: responses to augmented blood pressure oscillations J. Physiol., September 15, 2004; 559(3): 965 - 973. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Chapuis, E. Vidal-Petiot, V. Orea, C. Barres, and C. Julien Linear modelling analysis of baroreflex control of arterial pressure variability in rats J. Physiol., September 1, 2004; 559(2): 639 - 649. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. A. Griffin, R. Hacioglu, I. Abu-Amarah, R. Loutzenhiser, G. A. Williamson, and A. K. Bidani Effects of calcium channel blockers on "dynamic" and "steady-state step" renal autoregulation Am J Physiol Renal Physiol, June 1, 2004; 286(6): F1136 - F1143. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. K. Bidani, R. Hacioglu, I. Abu-Amarah, G. A. Williamson, R. Loutzenhiser, and K. A. Griffin "Step" vs. "dynamic" autoregulation: implications for susceptibility to hypertensive injury Am J Physiol Renal Physiol, July 1, 2003; 285(1): F113 - F120. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Schondorf, R. Stein, R. Roberts, J. Benoit, and W. Cupples Dynamic cerebral autoregulation is preserved in neurally mediated syncope J Appl Physiol, December 1, 2001; 91(6): 2493 - 2502. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. S. Pires, C. Julien, B. Chapuis, J. Sassard, and C. Barres Spontaneous renal blood flow autoregulation curves in conscious sinoaortic baroreceptor-denervated rats Am J Physiol Renal Physiol, January 1, 2002; 282(1): F51 - F58. [Abstract] [Full Text] [PDF]
|
|