Renal autoregulation: new perspectives regarding the protective and regulatory roles of the underlying mechanisms
Open Access
- 1 May 2006
- journal article
- review article
- Published by American Physiological Society in American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
- Vol. 290 (5), R1153-R1167
- https://doi.org/10.1152/ajpregu.00402.2005
Abstract
When the kidney is subjected to acute increases in blood pressure (BP), renal blood flow (RBF) and glomerular filtration rate (GFR) are observed to remain relatively constant. Two mechanisms, tubuloglomerular feedback (TGF) and the myogenic response, are thought to act in concert to achieve a precise moment-by-moment regulation of GFR and distal salt delivery. The current view is that this mechanism insulates renal excretory function from fluctuations in BP. Indeed, the concept that renal autoregulation is necessary for normal renal function and volume homeostasis has long been a cornerstone of renal physiology. This article presents a very different view, at least regarding the myogenic component of this response. We suggest that its primary purpose is to protect the kidney against the damaging effects of hypertension. The arguments advanced take into consideration the unique properties of the afferent arteriolar myogenic response that allow it to protect against the oscillating systolic pressure and the accruing evidence that when this response is impaired, the primary consequence is not a disturbed volume homeostasis but rather an increased susceptibility to hypertensive injury. It is suggested that redundant and compensatory mechanisms achieve volume regulation, despite considerable fluctuations in distal delivery, and the assumed moment-by-moment regulation of renal hemodynamics is questioned. Evidence is presented suggesting that additional mechanisms exist to maintain ambient levels of RBF and GFR within normal range, despite chronic alterations in BP and severely impaired acute responses to pressure. Finally, the implications of this new perspective on the divergent roles of the myogenic response to pressure vs. the TGF response to changes in distal delivery are considered, and it is proposed that in addition to TGF-induced vasoconstriction, vasodepressor responses to reduced distal delivery may play a critical role in modulating afferent arteriolar reactivity to integrate the regulatory and protective functions of the renal microvasculature.Keywords
This publication has 143 references indexed in Scilit:
- Function determines structure in the vasculature: lessons from insulin resistanceAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2005
- MECHANISMS MEDIATING PRESSURE NATRIURESIS: WHAT WE KNOW and WHAT WE NEED TO FIND OUTClinical and Experimental Pharmacology and Physiology, 2005
- Macula Densa Cell SignalingAnnual Review of Physiology, 2003
- Impact of Systemic Depulsation on Tissue Perfusion and Sympathetic Nerve ActivityThe Annals of Thoracic Surgery, 1996
- Renal ablation acutely transforms 'benign' hypertension to 'malignant' nephrosclerosis in hypertensive rats.Hypertension, 1994
- Renin expression in renal ablation.Hypertension, 1992
- Enhanced myogenic responsiveness of renal interlobular arteries in spontaneously hypertensive rats.Hypertension, 1992
- Abnormal pressure natriuresis. A cause or a consequence of hypertension?Hypertension, 1990
- Dietary protein suppresses feedback control of glomerular filtration in rats.JCI Insight, 1985
- Captopril-Induced Functional Renal Insufficiency in Patients with Bilateral Renal-Artery Stenoses or Renal-Artery Stenosis in a Solitary KidneyNew England Journal of Medicine, 1983