title: Ca(2+) signaling and membrane potential in descending vasa recta pericytes and endothelia.
abstract: 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 Ca(2+) concentration ([Ca(2+)](i)) and suppresses endothelial [Ca(2+)](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 [Ca(2+)](i) responses and that ANG II and bradykinin receptors exist separately on each cell type.
authors.affiliation: Division of Nephrology, University of Maryland School of Medicine, Baltimore 21201-1595, USA.
authors.forename: Kristie
authors.initials: K
authors.lastname: Rhinehart
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Pallone
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D007679:Kidney Medulla / Q000098:blood supply* / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects; D018408:Patch-Clamp Techniques; D020286:Pericytes / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D007202:Indicators and Reagents; D014665:Vasodilator Agents; D000804:Angiotensin II; D001920:Bradykinin