title: Angiotensin II stimulates the Na+/H+ exchanger in human umbilical vein endothelial cells via AT1 receptor.
abstract: Angiotensin II (Ang II) has an important role in cardiovascular regulation and in the control of electrolyte balance, and its role in the regulation of Na+ transcellular movements through its actions on the activity of Na+/K+ ATPase is well documented. We showed previously that human umbilical vein endothelial cells (HUVEC) express the Ang II type 1 (AT1) receptor, which mediates Ang II modulation of Na+/K+ ATPase activity (1). We here investigate the effects of Ang II on the activity of the Na+/H+ exchanger in HUVEC. When compared with controls, incubation of HUVEC for 20 min with different concentrations of Ang II provoked significant increases in Na+/H+ activity. The stimulation was dose dependent between 1 and 10 nM Ang II and varied with time of incubation up to 20 min. The maximal response, obtained with 10 nM Ang II after 20 min treatment, resulted in a 65% increment in Na+/H+ activity. Preincubation of HUVEC with 10 microM DuP753 blocked Na+/H+ activation by Ang II. These results suggest that the effects of Ang II on both the Na+/K+ ATPase and the Na+/H+ exchanger may increase the transendothelial flux of Na+ and are mediated by the AT1 receptor.
authors.affiliation: Dipartimento di Biologia, Università di Lecce, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Muscella
authors.forename: S
authors.initials: S
authors.lastname: Marsigliante
authors.forename: S
authors.initials: S
authors.lastname: Vilella
authors.forename: E
authors.initials: E
authors.lastname: Jimenez
authors.forename: C
authors.initials: C
authors.lastname: Storelli
mesh_terms: D000804:Angiotensin II / Q000502:physiology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D005452:Fluoresceins; D005456:Fluorescent Dyes; D006490:Hemostatics / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007476:Ionophores / Q000494:pharmacology; D009550:Nigericin / Q000494:pharmacology; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000502:physiology*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013917:Thrombin / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D006490:Hemostatics; D007476:Ionophores; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D017923:Sodium-Hydrogen Exchangers; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D013917:Thrombin; D000254:Sodium-Potassium-Exchanging ATPase; D009550:Nigericin