| Autor: |
Yakushev, Sergej, Band, Mark, Tissot van Patot, Martha C., Gassmann, Max, Avivi, Aaron, Bogdanova, Anna |
| Zdroj: |
American Journal of Physiology: Heart & Circulatory Physiology; Dec2012, Vol. 303 Issue 11, pH1332-H1343, 12p |
| Abstrakt: |
Oxygen-induced regulation of Na,K-ATPase was studied in rat myocardium. In rat heart, Na,K-ATPase responded to hypoxia with a dosedependent inhibition in hydrolytic activity. Inhibition of Na,KATPase in hypoxic rat heart was associated with decrease in nitric oxide (NO) production and progressive oxidative stress. Accumulation of oxidized glutathione (GSSG) and decrease in NO availability in hypoxic rat heart were followed by a decrease in S-nitrosylation and upregulation of S-glutathionylation of the catalytic α-subunit of the Na,K-ATPase. Induction of S-glutathionylation of the α-subunit by treatment of tissue homogenate with GSSG resulted in complete inhibition of the enzyme in rat a myocardial tissue homogenate. Inhibitory effect of GSSG in rat sarcolemma could be significantly decreased upon activation of NO synthases. We have further tested whether oxidative stress and suppression of the Na,K-ATPase activity are observed in hypoxic heart of two subterranean hypoxia-tolerant blind mole species (Spalax galili and Spalax judaei). In both hypoxiatolerant Spalax species activity of the enzyme and tissue redox state were maintained under hypoxic conditions. However, localization of cysteines within the catalytic subunit of the Na,K-ATPase was preserved and induction of S-glutathionylation by GSSG in tissue homogenate inhibited the Spalax ATPase as efficiently as in rat heart. The obtained data indicate that oxygen-induced regulation of the Na,K-ATPase in the heart is mediated by a switch between Sglutathionylation and S-nitrosylation of the regulatory thiol groups localized at the catalytic subunit of the enzyme. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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