Modulation of Ion Channels by Hydrogen Sulfide

Significance: Evidence of the ability of the gasotransmitter hydrogen sulfide (H2S) to serve as a regulator of many physiological functions, including control of blood pressure, regulation of cardiac function, protection of neurons, and cardiomyocytes against apoptosis, and in pain sensation is accumulating. However, the mechanisms accounting for its many actions are not yet well understood. Recent Advances: Following the pioneering studies of the regulation of N-methyl-d-aspartate receptors and ATP-sensitive K+ channels by H2S, data continue to emerge indicating that H2S modulates other ion channel types. This article reviews the numerous, yet diverse, types of ion channels now reported to be regulated by H2S. Critical Issues: Currently, a critical issue within this field is to determine the mechanisms by which H2S regulates ion channels, as well as other target proteins. Mechanisms to account for regulation include direct channel protein sulfhydration, channel redox modulation, effects mediated by interactions with other gasotransmitters (carbon monoxide and nitric oxide), and indirect effects, such as modulation of channel-regulating kinases. Through such modulation of ion channels, novel roles for H2S are emerging as important factors in both physiological and pathological processes. Future Directions: Increasing current awareness and understanding of the roles and mechanisms of action of ion channel regulation by H2S will open opportunities for therapeutic intervention with clear clinical benefits, and inform future therapies. In addition, more sensitive methods for detecting relevant physiological concentrations of H2S will allow for clarification of specific ion channel regulation with reference to physiological or pathophysiological settings. Antioxid. Redox Signal. 17, 95-105.