Special Communication Ca signaling and membrane potential in descending vasa recta pericytes and endothelia

Rhinehart, Kristie, Zhong Zhang, and Thomas L. Pallone. Ca2 signaling and membrane potential in descending vasa recta pericytes and endothelia. Am J Physiol Renal Physiol 283: F852–F860, 2002. First published April 23, 2002; 10.1152/ajprenal.00065.2002.—We devised a method for removal of pericytes from isolated descending vasa recta (DVR). After enzymatic digestion, aspiration of a descending vas rectum into a micropipette strips the pericytes from the abluminal surface. Pericytes and denuded endothelia can be recovered for separate study. Using fura 2-loaded preparations, we demonstrated that 10 nM angiotensin II (ANG II) elevates pericyte intracellular Ca2 concentration ([Ca2 ]i) and suppresses endothelial [Ca2 ]i. The anion transport blocker probenecid helps retain fura 2 in the pericyte cytoplasm. DVR endothelia were accessed for membrane potential measurement by perforated-patch whole cell recording by using the pericyte-stripping technique and by turning nondigested vessels inside out with concentric micropipettes. By either method of access, 10 nM ANG II depolarized (n 20) and 100 nM bradykinin hyperpolarized (n 25) the endothelia. We conclude that isolated endothelia and pericytes remain functional for study of [Ca2 ]i responses and that ANG II and bradykinin receptors exist separately on each cell type.