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The role of hydrogen peroxide in the contractile response to angiotensin II.

Authors :
Torrecillas G
Boyano-Adánez MC
Medina J
Parra T
Griera M
López-Ongil S
Arilla E
Rodríguez-Puyol M
Rodríguez-Puyol D
Source :
Molecular pharmacology [Mol Pharmacol] 2001 Jan; Vol. 59 (1), pp. 104-12.
Publication Year :
2001

Abstract

In the last years, reactive oxygen species (ROS) have been proposed as mediators of proliferative/hypertrophic responses to angiotensin II (Ang II), both in vivo and in vitro. However, the hypothesis that the Ang II-dependent cell contraction could be mediated by ROS, particularly H2O2, has not been tested. Present experiments were devoted to test this hypothesis and to analyze the possible mechanisms involved. Catalase (CAT) prevented the increased myosin light chain phosphorylation and the decreased planar cell surface area (PCSA) induced by 1 microM Ang II in cultured rat vascular smooth muscle cells (VSMC). This preventive effect of CAT was also detected when 1 microM platelet-activating factor (PAF) was used as a contractile agonist instead of Ang II. Similar results were found when using horseradish peroxidase as an H2O2 scavenger or cultured rat mesangial cells. In vascular smooth muscle cells, CAT modified neither the binding of labeled Ang II nor the Ang II-induced inositol 1,4,5-trisphosphate (IP3) synthesis. However, it completely abolished the Ang II-dependent calcium peak, in a dose-dependent fashion. CAT-loaded cells (increased intracellular CAT concentration over 3-fold) did not show either a decreased PCSA or an increased intracellular calcium concentration after Ang II treatment. Ang II stimulated the H2O2 synthesis by cultured cells, and the presence of CAT in the extracellular compartment significantly diminished the Ang II-dependent increased intracellular H2O2 concentration. The physiological importance of these findings was tested in rat thoracic aortic rings: CAT prevented the contraction elicited by Ang II. In summary, present experiments point to H2O2 as a critical intracellular metabolite in the regulation of cell contraction.

Details

Language :
English
ISSN :
0026-895X
Volume :
59
Issue :
1
Database :
MEDLINE
Journal :
Molecular pharmacology
Publication Type :
Academic Journal
Accession number :
11125030
Full Text :
https://doi.org/10.1124/mol.59.1.104