Theoretical Assessment of Renal Autoregulatory Mechanisms.

Theoretical Assessment of Renal Autoregulatory Mechanisms.
Am J Physiol Renal Physiol. 2014 Mar 12;
Authors: Sgouralis I, Layton AT
Abstract
A mathematical model of renal hemodynamics is used to assess the individual contributions of the tubuloglomerular feedback (TGF) mechanism and the myogenic response to glomerular filtration rate regulation in the rat kidney. The model represents an afferent arteriole segment, glomerular filtration, and a short loop of Henle. The afferent arteriole model exhibits myogenic response, which is activated by hydrostatic pressure variations to induce changes in membrane potential and vascular muscle tone. The tubule model predicts tubular fluid and Cl00; transport. Macula densa Cl00; concentration is sensed as the signal for TGF, which acts to constrict or dilate the afferent arteriole. With this configuration, the model afferent arteriole maintains stable glomerular filtration rate within a physiologic range of perfusion pressure (80-180 mmHg). The contribution of TGF to overall autoregulation is significant only within a narrow band of perfusion pressure values (80-110 mmHg). Model simulations of ramp-like perfusion pressure perturbations agree well with findings by Flemming et al. (J Am Soc Nephrol 12:2253- 2262, 2001), which indicate that changes in vascular conductance is markedly sensitive to pressure velocity. That asymmetric response is attributed to the rate-dependent kinetics of the myogenic mechanism....

Source: Am J Physiol Renal P... - March 12, 2014 Category: Urology & Nephrology Authors: Sgouralis I, Layton AT Tags: Am J Physiol Renal Physiol Source Type: research