Calcium Dynamics Underlying the Afferent Arteriole Myogenic Response.

Calcium Dynamics Underlying the Afferent Arteriole Myogenic Response.
Am J Physiol Renal Physiol. 2013 Oct 30;
Authors: Edwards A, Layton AT
Abstract
The renal afferent arteriole reacts to an elevation in blood pressure with an increase in muscle tone and a decrease in luminal diameter. This effect, known as the myogenic response, is believed to stabilize glomerular filtration and to protect the glomerulus from systolic blood pressure increases, especially in hypertension. To study the mechanisms underlying the myogenic response, we developed a mathematical model of intracellular Ca(2+) signaling in an afferent arteriole smooth muscle cell. The model represents detailed transmembrane ionic transport, intracellular Ca(2+) dynamics, the kinetics of myosin light chain phosphorylation, and the mechanical behavior of the cell. It assumes that the myogenic response is initiated by pressure-induced changes in the activity of non-selective cation channels. Our model predicts spontaneous vasomotion at physiological luminal pressures, and KCl- and diltiazem-induced diameter changes comparable to experimental findings. The time-periodic oscillations stem from the dynamic exchange of Ca(2+) between the cytosol and the sarcoplasmic reticulum, coupled to the stimulation of Ca(2+)-activated potassium (KCa) and chloride (ClCa) channels, and the modulation of voltage-activated L-type channels; blocking sarco/endoplasmic reticulum Ca(2+) pumps or ryanodyne rece...

Source: Am J Physiol Renal P... - October 30, 2013 Category: Urology & Nephrology Authors: Edwards A, Layton AT Tags: Am J Physiol Renal Physiol Source Type: research