Podocyte electrophysiology, in vivo and in vitro

Abstract

Podocytes are the most differentiated cell types in the glomerulus, which have been assumed to participate in the regulation of the ultrafiltration coefficient Kf. In podocytes in vivo and in vitro vasoactive agonists, such as angiotensin II and acetylcholine, increase the free cytosolic Ca2+ concentration via a release of Ca2+ from intracellular stores and an influx of Ca2+ from the extracellular space. An increase of the cytosolic Ca2+ in podocytes activates Cl- channels in podocytes in vivo and in vitro, resulting in a depolarization of podocytes. In vitro studies have shown that in addition to Ca2+ activated Cl- channels, cAMP-activated Cl- channels and Ca2+-activated K+ channels are present in cultured podocytes. The characterization of the signaling pathways that regulate ion channels in podocytes may be important in the understanding of the regulation of the ultrafiltration coefficient Kf. This review summarizes the currently known electrophysiological properties of podocytes.© 2002 Wiley-Liss, Inc.