Internephron Coupling Increases the Efficiency of Dynamic Autoregulation

Abstract

In the kidney, dynamic autoregulation is provided by the response of the pre‐glomerular vascular resistance to time‐dependent perturbations of blood pressure. The two major autoregulatory mechanisms are the myogenic response, which is activated by afferent arteriole blood pressure, and tubuloglomerular feedback, which is activated by deviations in distal nephron chloride concentration. While the two mechanisms operate primarily on the single nephron level, signals that are transmitted through the supplying vasculature give rise to substantial internephron interactions. To study the impact of internephron coupling, we develop a mathematical model of the nephrovascular tree and apply the model to investigate the extent to which buffering of transient pressure perturbations is achieved. The model consists of coupled nephrovascular units; each unit represents an afferent arteriole, a glomerulus, and a nephron. The model includes superficial and juxtamedullary nephrons. Model simulations indicate effective buffering of pressure perturbations at low frequencies and slight amplification at high frequencies, in agreement with experimental observations of whole organ hemodynamics. Furthermore, the model predicts that internephron coupling increases the autoregulatory efficiency of the neprhovascular tree.Support or Funding InformationNSF DBI‐1300426