Mechanosensitive channels (MSCs) are special membrane proteins that can convert mechanical stimulation into electrical or chemical signals. These channels have become potential targets for ultrasonic neuromodulation due to their properties. The good spatial resolution and focusing effect of ultrasound make it theoretically possible to achieve non-invasive whole-brain localization. Therefore, ultrasonic neuromodulation is a promising method for performing physical neuromodulation and treating neurological disorders. To date, only a few ion channels have been reported to be activated by ultrasound, while recent research has identified more channels with mechanosensitive properties. Moreover, the opening process and mechanism of MSCs under ultrasound excitation remain unknown. This review provides an overview on recent research advances and applications in MSCs, including large conductance mechanosensitive channels, transient receptor potential channels, degenerated protein/epithelial sodium channels, two-pore potassium channels, and piezo channels. These findings will facilitate future studies and applications of ultrasonic neuromodulation.
Ultrasonics ; Ion Channels/metabolism*

Ion channels mediate ion transport across membranes, and play vital roles in processes of matter exchange, energy transfer and signal transduction in living organisms. Recently, structural studies of ion channels have greatly advanced our understanding of their ion selectivity and gating mechanisms. Structural studies of voltage-gated potassium channels elucidate the structural basis for potassium selectivity and voltage-gating mechanism; structural studies of voltage-gated sodium channels reveal their slow and fast inactivation mechanisms; and structural studies of transient receptor potential (TRP) channels provide complex and diverse structures of TRP channels, and their ligand gating mechanisms. In the article we summarize recent progress on ion channel structural biology, and outlook the prospect of ion channel structural biology in the future.
Ion Channel Gating ; physiology ; Ion Channels ; Voltage-Gated Sodium Channels ; chemistry ; metabolism

Dantrolene sodium in vitro inhibited the ATP-dependent efflux of calcium from human Fed cells, the Ca++-ATPase activity of red blood cell membrane fragments (RBCMF) and passive calcium binding to RBCMF. These effects were obtained With concentrations of dantrolene sodium between 2.5 and 20 uM. However the passive influx of Ca++ was measured at 37 degrees C in cells pretreated to abolish Ca++ pumping and was not influenced by dantrolene sodium. From these results, it was concluded that dantrolene sodium inhibits an active Ca++ extrusion across the red cell membrane by inhibiting Ca++-ATPase activity which is intimately involved with the Ca++ transport mechanism in the red cell membrane.
Calcium/metabolism* ; Dantrolene/pharmacology* ; Erythrocyte Membrane/drug effects* ; Erythrocyte Membrane/metabolism ; Human ; Ion Channels/drug effects* ; Ion Channels/metabolism

As a non-invasive approach, sonogenetics is applied to control neuronal activity. The mechanosensitive channel(MSC), which has low threshold of responding to ultrasound, may be the alternative solution. Sonogenetics is the technique that activates the MSC expressed in targeted neurons by low intensity ultrasound, thus achieve the neuromodulation. In this review, we introduce the mechanosensitive channel of large conductance, transient receptor potential, channels of the two-pore-domain potassium family, Piezo and the recent progress on their application in sonogenetics.
Biomechanical Phenomena ; Ion Channels ; metabolism ; Neurons ; Ultrasonic Waves

Hv1 is the only voltage-gated proton-selective channel in mammalian cells. It contains a conserved voltage-sensor domain, shared by a large class of voltage-gated ion channels, but lacks a pore domain. Its primary role is to extrude protons from the cytoplasm upon pH reduction and membrane depolarization. The best-known function of Hv1 is the regulation of cytosolic pH and the nicotinamide adenine dinucleotide phosphate oxidase-dependent production of reactive oxygen species. Accumulating evidence indicates that Hv1 is expressed in nervous systems, in addition to immune cells and others. Here, we summarize the molecular properties, distribution, and physiological functions of Hv1 in the peripheral and central nervous systems. We describe the recently discovered functions of Hv1 in various neurological diseases, including brain or spinal cord injury, ischemic stroke, demyelinating diseases, and pain. We also summarize the current advances in the discovery and application of Hv1-targeted small molecules in neurological diseases. Finally, we discuss the current limitations of our understanding of Hv1 and suggest future research directions.
Animals ; Protons ; Ion Channels/metabolism* ; Reactive Oxygen Species/metabolism* ; Brain/metabolism* ; NADPH Oxidases ; Mammals/metabolism*

The different concentration of specific ion species and the electrodiffusion of the ions down their electrochemical gradient generate transmembrane potential. The regulation of membrane potential for the function of numerous membrane proteins such as ion channels, transporters, pumps and enzymes plays primary role in the conversion of extracellular electric stimulation into a sequence of intracellular biochemical signals. Some ion channels regulated by membrane potential are well known, and the membrane non-ion channels protein is also modulated physiologically by membrane potential.
Humans ; Ion Channel Gating ; physiology ; Ion Channels ; metabolism ; Membrane Potentials ; physiology ; Phosphoric Monoester Hydrolases ; metabolism ; Receptors, G-Protein-Coupled ; metabolism

Neuronomodulation refers to the modulation of neural conduction and synaptic transmission (i.e., the conduction process involved in synaptic transmission) of excitable neurons via changes in the membrane potential in response to chemical substances, from spillover neurotransmitters to paracrine or endocrine hormones circulating in the blood. Neuronomodulation can be direct or indirect, depending on the transduction pathways from the ligand binding site to the ion pore, either on the same molecule, i.e. the ion channel, or through an intermediate step on different molecules. The major players in direct neuronomodulation are ligand-gated or voltage-gated ion channels. The key process of direct neuronomodulation is the binding and chemoactivation of ligand-gated or voltage-gated ion channels, either orthosterically or allosterically, by various ligands. Indirect neuronomodulation involves metabotropic receptor-mediated slow potentials, where steroid hormones, cytokines, and chemokines can implement these actions. Elucidating neuronomodulation is of great significance for understanding the physiological mechanisms of brain function, and the occurrence and treatment of diseases.
Ligands ; Neurons/metabolism* ; Synaptic Transmission/physiology* ; Ion Channels/metabolism* ; Hormones/metabolism*

Voltage is an important parameter that regulates the conductance of both intercellular and plasma membrane channels (undocked hemichannels) formed by the 21 members of the mammalian connexin gene family. Connexin channels display two forms of voltage-dependence, rectification of ionic currents and voltage-dependent gating. Ionic rectification results either from asymmetries in the distribution of fixed charges due to heterotypic pairing of different hemichannels, or by channel block, arising from differences in the concentrations of divalent cations on opposite sides of the junctional plaque. This rectification likely underpins the electrical rectification observed in some electrical synapses. Both intercellular and undocked hemichannels also display two distinct forms of voltage-dependent gating, termed Vj (fast)-gating and loop (slow)-gating. This review summarizes our current understanding of the molecular determinants and mechanisms underlying these conformational changes derived from experimental, molecular-genetic, structural, and computational approaches.
Animals ; Connexins/chemistry/*metabolism ; Humans ; *Ion Channel Gating ; Ion Channels/chemistry/*metabolism ; Molecular Dynamics Simulation ; Protein Conformation

In the retina, pH fluctuations may play an important role in adapting retinal responses to different light intensities and are involved in the fine tuning of visual perception. Acidosis occurs in the subretinal space (SRS) under pathological conditions such as age-related macular degeneration (AMD). Although it is well known that many transporters in the retinal pigment epithelium (RPE) cells can maintain pH homeostasis efficiently, other receptors in RPE may also be involved in sensing acidosis, such as acid-sensing ion channels (ASICs). In this study, we investigated whether ASIC1a was expressed in the RPE cells and whether it was involved in the function of these cells. Real-time RT-PCR and Western blotting were used to analyze the ASIC1a expression in ARPE-19 cells during oxidative stress induced by hydrogen peroxide (H(2)O(2)). Furthermore, inhibition or over-expression of ASIC1a in RPE cells was obtained using inhibitors (amiloride and PCTx1) or by the transfection of cDNA encoding hASIC1a. Cell viability was determined by using the MTT assay. The real-time RT-PCR and Western blotting results showed that both the mRNA and protein of ASIC1a were expressed in RPE cells. Inhibition of ASICs by amiloride in normal RPE cells resulted in cell death, indicating that ASICs play an important physiological role in RPE cells. Furthermore, over-expression of ASIC1a in RPE cells prolonged cell survival under oxidative stress induced by H(2)O(2). In conclusion, ASIC1a is functionally expressed in RPE cells and may play an important role in the physiological function of RPE cells by protecting them from oxidative stress.
Acid Sensing Ion Channels ; metabolism ; Cell Line ; Humans ; Ion Channel Gating ; physiology ; Oxidative Stress ; physiology ; Retinal Pigment Epithelium ; cytology ; metabolism

AIMTo investigate the action and mechanism of Syn-1A in reversing the activation of K(ATP) channel induced by weak acidic pH.

METHODSThe patches excised from Kir6.2/SUR2A expressing HEK-293 cells were used to establish inside-out configuration. To examine the actions of weak acidic pH in activation of the channel and the reverse action of Syn-1A on it, the inside-out patches were continuously perfused with the solution of pH from 7.4, 7.0, 6.8, 6.5 to 6.0 with or without Syn-1A. In vitro binding was employed to study the influence of different pH to the binding of Syn-1A to SUR2A subunit.

RESULTSSyn-1A blocked pH 6.5, 6.8 and 7.0 induced activation of the channel, and Syn-1A binding to SUR2A were increased by reducing pH from 7.4 to 6.0.

CONCLUSIONSyn-1A would assert some inhibition of the KATP channels, which might temper the fluctuation of acidic pH-induced K(ATP) channel opening that could induce fatal re-entrant arrhythmias.

HEK293 Cells ; Humans ; Hydrogen-Ion Concentration ; KATP Channels ; metabolism ; Patch-Clamp Techniques ; Potassium Channels ; metabolism ; Potassium Channels, Inwardly Rectifying ; metabolism ; Syntaxin 1 ; pharmacology