Research Article
Volume 4 Issue 10 - 2020
MgATPase Activity May be Dispensable for the Opening of Mitochondrial Katp Channel by Diazoxide
Olga V Akopova*
Circulation Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine
*Corresponding Author: Olga V Akopova, Circulation Department, Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine.
Received: September 18, 2020; Published: September 30, 2020




Abstract

It is generally accepted that activation of mKATP channels by diazoxide and others KATP channels openers (KCOs), similarly to sKATP channels, require MgATPase activity of the receptor SUR subunit, and the presence of MgATP as the prerequisite for the channel activation. However, literary data obtained on isolated mitochondria were controversial in this regard and numerous studies showed activation of mitochondrial K+ uptake by KCOs in the absence of MgATP. Recently we have shown high sensitivity of ATPsensitive K+ transport of rat liver mitochondria to DZ in the absence of MgATP. Considering that KATP channels of different cell types may exhibit different sensitivity to DZ, the purpose of this work was to examine possible tissue specificity of this phenomenon and compare the effect of DZ on ATP-sensitive K+ transport in brain and liver mitochondria in the absence and the presence of MgATP. On isolated mitochondria, we have found that full activation of K+ transport of both liver and brain mitochondria occurred at < 0.5 μM of DZ. MgATP shifted the sensitivity of K+ transport to DZ to micromolar concentration scale. Without MgATP, activation of ATPsensitive K+ transport was verified by the blockage with MgATP, glibenclamide, and 5-hydroxydecanoate, which allowed for its attribution to mKATP channels activity. Based on the experiments, we hypothesized that MgATP may be dispensable for the activation of native mKATP channel by DZ, and that mKATP channels might comprise high affinity sites for DZ binding in the absence of Mg∙ATP. Obtained results reveal novel aspects of mKATP channels activation by DZ.

Keywords: KATP Channels; Mitochondria; Brain; Liver; K+ Transport; Diazoxide

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Citation: Olga V Akopova. “MgATPase Activity May be Dispensable for the Opening of Mitochondrial Katp Channel by Diazoxide". EC Diabetes and Metabolic Research 4.10 (2020): 18-25.

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