| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Institut für Physiologie und Pathophysiologie, Universität Heidelberg, D-69120 Heidelberg; and 2 Institut für Physiologie, Universität Hamburg, D-20246 Hamburg, Germany
The time course of the autoregulatory response of renal blood flow (RBF) to a step increase in renal arterial pressure (RAP) was studied in conscious dogs. After RAP was reduced to 50 mmHg for 60 s, renal vascular resistance (RVR) decreased by 50%. When RAP was suddenly increased again, RVR returned to baseline with a characteristic time course (control; n = 15): within the first 10 s, it rose rapidly to 70% of baseline (response 1), thus already comprising 40% of the total RVR response. Thereafter, it increased at a much slower rate until it started to rise rapidly again at 20-30 s after the pressure step (response 2). After passing an overshoot of 117% at 43 s, RVR returned to baseline values. Similar responses were observed after RAP reduction for 5 min or after complete occlusions for 60 s. When tubuloglomerular feedback (TGF) was inhibited by furosemide (40 mg iv, n = 12), response 1 was enhanced, providing 60% of the total response, whereas response 2 was completely abolished. Instead, RVR slowly rose to reach the baseline at 60 s (response 3). The same pattern was observed when furosemide was given at a much higher dose (>600 mg iv; n = 6) or in combination with clamping of the plasma levels of nitric oxide (n = 6). In contrast to RVR, vascular resistance in the external iliac artery after a 60-s complete occlusion started to rise with a delay of 4 s and returned to baseline within 30 s. It is concluded that, in addition to the myogenic response and the TGF, a third regulatory mechanism significantly contributes to RBF autoregulation, independently of nitric oxide. The three mechanisms contribute about equally to resting RVR. The myogenic response is faster in the kidney than in the hindlimb.
renal hemodynamics; tubuloglomerular feedback; myogenic response
This article has been cited by other articles:
|
|
 |
|
  K. H. Chon, Y. Zhong, L. C. Moore, N. H. Holstein-Rathlou, and W. A. Cupples Analysis of nonstationarity in renal autoregulation mechanisms using time-varying transfer and coherence functions Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2008; 295(3): R821 - R828. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-J. Wang, N. G. Shrive, K. H. Parker, and J. V. Tyberg Effects of vasoconstriction and vasodilatation on LV and segmental circulatory energetics Am J Physiol Heart Circ Physiol, March 1, 2008; 294(3): H1216 - H1225. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Just and W. J. Arendshorst A novel mechanism of renal blood flow autoregulation and the autoregulatory role of A1 adenosine receptors in mice Am J Physiol Renal Physiol, November 1, 2007; 293(5): F1489 - F1500. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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]
|
|
|
|
 |
|
 A. Just and W. J. Arendshorst Nitric oxide blunts myogenic autoregulation in rat renal but not skeletal muscle circulation via tubuloglomerular feedback J. Physiol., December 15, 2005; 569(3): 959 - 974. [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]
|
|
|
|
|
|
D. D. O'Leary, J. K. Shoemaker, M. R. Edwards, and R. L. Hughson Spontaneous beat-by-beat fluctuations of total peripheral and cerebrovascular resistance in response to tilt Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2004; 287(3): R670 - R679. [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]
|
|
|
|
|
|
T. Wronski, E. Seeliger, P. B. Persson, C. Forner, C. Fichtner, J. Scheller, and B. Flemming The step response: a method to characterize mechanisms of renal blood flow autoregulation Am J Physiol Renal Physiol, October 1, 2003; 285(4): F758 - F764. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Just and W. J. Arendshorst Dynamics and contribution of mechanisms mediating renal blood flow autoregulation Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2003; 285(3): R619 - R631. [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]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
