Modeling Autoregulation of the Afferent Arteriole of the Rat Kidney

One of the key autoregulatory mechanisms that control blood flow in the kidney is the myogenic response. Subject to increased pressure, the renal afferent arteriole responds with an increase in muscle tone and a decrease in diameter. To investigate the myogenic response of an afferent arteriole segment of the rat kidney, we extend a mathematical model of an afferent arteriole cell. For each cell, we include detailed Ca2+ signaling, transmembrane transport of major ions, the kinetics of myosin light chain phosphorylation, as well as cellular contraction and wall mechanics. To model an afferent arteriole segment, a number of cell models are connected in series by gap junctions, which link the cytoplasm of neighboring cells. Blood flow through the afferent arteriole is modeled using Poiseuille flow. Simulation of an inflow pressure up-step leads to a decrease in the diameter for the proximal part of the vessel (vasoconstriction) and to an increase in proximal vessel diameter (vasodilation) for an inflow pressure down-step. Through its myogenic response, the afferent arteriole segment model yields approximately stable single-nephron glomerular filtration rate for a physiological range of inflow pressures (100–160 ∗The first and second authors made equal contributions. Veronica Ciocanel Division of Applied Mathematics, Brown University, Rhode Island, USA e-mail: veronica [email protected] Tracy L. Stepien School of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona, USA e-mail: [email protected] Aurélie Edwards Sorbonne Universités, UPMC Univ Paris 06, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS 1138, CNRS ERL 8228, Centre de Recherche des Cordeliers, Paris, France e-mail: [email protected] Anita T. Layton Department of Mathematics, Duke University, North Carolina, USA e-mail: [email protected]