Abstract

Mitochondrial potassium channels control potassium influx into the mitochondrial matrix and thus regulate mitochondrial membrane potential, volume, respiration, and synthesis of reactive oxygen species (ROS). It has been found that pharmacological activation of mitochondrial potassium channels during ischemia/reperfusion (I/R) injury activates cytoprotective mechanisms resulting in increased cell survival. In cancer cells, the inhibition of these channels leads to increased cell death. Therefore, mitochondrial potassium channels are intriguing targets for the development of new pharmacological strategies. In most cases, however, the substances that modulate the mitochondrial potassium channels have a few alternative targets in the cell. This may result in unexpected or unwanted effects induced by these compounds. In our review, we briefly present the various classes of mitochondrial potassium (mitoK) channels and describe the chemical compounds that modulate their activity. We also describe examples of the multidirectional activity of the activators and inhibitors of mitochondrial potassium channels.

Highlights

  • Earlier studies on isolated mitochondria have indicated that the transport of potassium ions is an important element in regulating their volume

  • Over the last dozen years, emerging research on potassium channels clearly indicates their involvement in both protective processes and processes influencing cell death. It seems that one of the targets for the regulation of both cellular protection and apoptotic and necrotic processes is the potassium channels found in the inner mitochondrial membrane

  • A well-documented phenomenon is a protection of heart muscle cells from I/R injury with the use of small-molecule chemical compounds and potassium channel activators of the inner mitochondrial membrane (IMM), e.g., diazoxide and NS1619

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Summary

Introduction

Earlier studies on isolated mitochondria have indicated that the transport of potassium ions is an important element in regulating their volume. 5-HD is described as a relatively selective inhibitor of mitoKATP channels, and it does not inhibit plasma membrane KATP channels [6,23] All these compounds either have well-described alternative targets in the cell or induce cellular processes, which makes it difficult to reliably assess the detailed mechanism of their operation [26]. Nicorandil can induce cytoprotection in dystrophin-deficient cardiomyocytes, and these effects are only partially reversed by the mitoKATP blocker 5-HD [50] Another recent example of the bidirectional activity of nicorandil can be seen in the regulation of the expression of selected genes, such as heme oxygenase-1 or interleukin-8, by nicorandil in human umbilical vein endothelial cells (HUVECs).

Mitochondrial Calcium-Activated Potassium Channels
Large Conductance Calcium-Activated Potassium Channels
Intermediate Conductance Calcium-Activated Potassium Channels
Small Conductance Calcium-Activated Potassium Channels
Mitochondrial Voltage-Dependent Potassium Channels
Mitochondrial Sodium-Activated Potassium Channels
Pharmacology of Mitochondrial HCN Channels
Findings
Summary and Perspectives
Full Text
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