H2O2 AS A REGULATOR OF VASCULAR CONTRACTION
RADOSLAVA EMILOVA1, DANIELA DIMITROVA2, MITKO MLADENOV3, TEODORA DANEVA4, KREMENA MITOVA4, PLAMEN PADESHKI5, LUBOMIR LUBOMIROV6, MARIELA CHICHOVA1, HRISTO GAGOV1*
1 – Sofia University St. Kliment Ohridski, Faculty of Biology, Department of Animal and Human Physiology, Sofia, Bulgaria
2 – Bulgarian Academy of Sciences, Institute of Biophysics and Biomedical Engineering, Department of Excitable Structures, Sofia, Bulgaria
3 – University of Skopje Sts. Cyril and Methodius, Faculty of Natural Sciences and Mathematics, Institute of Biology, Skopje, Macedonia
4 – Bulgarian Academy of Sciences, Institute of Biology and Immunology of Reproduction, Department of Immunobiology of Reproduction, Sofia, Bulgaria
5 – National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria
6 – Institute of Vegetative Physiology, University of Cologne, Germany
*Corresponding author: hgagov@abv.bg
Keywords: reactive oxygen species, hydrogen peroxide, artery, NADPH oxidases, smooth muscle
Abstract: The reactive oxygen species, hydrogen peroxide (H2O2), hydroxyl radical (*OH) and superoxide anion (O2*-), participate as signal molecules in the paracrine regulation of vascular wall function. The role of H2O2-producing enzymes’ (NADPH oxidases) activation and the involvement of H2O2 in arterial smooth muscle contraction under physiological and pathological conditions are discussed in details. Pleiotropic signal pathways as activation of Ca2+ entry through L-type and non-L-type voltage gated Ca2+ channels, different types K+ channels, COX-derived thromboxane A2 receptor agonist and NADPH oxidase-derived superoxide, as well as stimulation of MAP kinase, Rho kinase and soluble guanylate cyclase, play a key role in the amplification of H2O2 triggered signal mechanisms. Thus, H2O2 may either increase or decrease the artery contraction depending on the species and vascular bed by multiple intracellular targets. The increasing amount of new data gives rise to the conception of the important role of H2O2 as a regulator of vascular functions in health and under different pathological conditions like diabetes, atherosclerosis, obesity, aging, etc. The participation of oxygen containing reactive nitrogen species as peroxynitrite (ONOO*-) and nitric oxide (NO) in vascular function is also reviewed.