10,298 results match your criteria channel opening

Connexin 46 and connexin 50 gap junction channel properties are shaped by structural and dynamic features of their N-terminal domains.

J Physiol 2021 Apr 20. Epub 2021 Apr 20.

Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.

Key Points: Gap junctions formed by different connexins are expressed throughout the body and harbor unique channel properties that have not been fully defined mechanistically. Recent structural studies by Cryo-EM have produced high-resolution models of the related but functionally distinct lens connexins (Cx50 and Cx46) captured in a stable open state, opening the door for structure-function comparison. Here, we conducted comparative MD simulation and electrophysiology studies to dissect the isoform-specific differences in Cx46 and Cx50 intercellular channel function. Read More

View Article and Full-Text PDF

Tansley Review No. 21 Plant ion channels: whole-cell and single channel studies.

Mark Tester

New Phytol 1990 Mar;114(3):305-340

Botany School, Downing St, Cambridge, CB2 3EA, UK.

Ion channels are proteins which catalyse rapid, passive, electrogenic uniport of ions through pores spanning an otherwise poorly permeable lipid bilayer. Among other processes, fluxes through ion channels are responsible for action potentials - large, transient changes in membrane potential which have been known of in plants for over 100 years. Much disparate information on ion channels in plant cells has accumulated over the past few years. Read More

View Article and Full-Text PDF

Involvement of TRPC5 channels, inwardly rectifying K channels, PLCβ and PIP in vasopressin-mediated excitation of medial central amygdala neurons.

J Physiol 2021 Apr 19. Epub 2021 Apr 19.

Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND58203, USA.

Key Points: Activation of V vasopressin receptors facilitates neuronal excitability in the medial nucleus of central amygdala (CeM) V receptor activation excites about 80% CeM neurons by opening a cationic conductance and about 20% CeM neurons by suppressing an inwardly rectifying K (Kir) channels The cationic conductance activated by V receptors is identified as TRPC5 channels PLCβ-mediated depletion of PIP is involved in V receptor-elicited excitation of CeM neurons Intracellular Ca release and PKC are unnecessary for V receptor-mediated excitation of CeM neurons ABSTRACT: Arginine vasopressin (AVP) serves as a hormone in the periphery to modulate water homeostasis and a neuromodulator in the brain to regulate a diverse range of functions including anxiety, social behaviors, cognitive activities and nociception. The amygdala is an essential brain region involved in modulating defensive and appetitive behaviors, pain, and alcohol use disorders. Whereas activation of V receptors in the medial nucleus of the central amygdala (CeM) increases neuronal excitability, the involved ionic and signaling mechanisms have not been determined. Read More

View Article and Full-Text PDF

Upregulated SOCC and IP3R calcium channels and subsequent elevated cytoplasmic calcium signaling promote nonalcoholic fatty liver disease by inhibiting autophagy.

Mol Cell Biochem 2021 Apr 17. Epub 2021 Apr 17.

Department of General Practice, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, 310053, Zhejiang, China.

Nonalcoholic fatty liver disease (NAFLD) is related to elevated cytoplasmic calcium signaling in hepatocytes, which may be mediated by store-operated calcium channel (SOCC) and inositol triphosphate receptor (IP3R). However, the regulatory effect of calcium signaling on lipid accumulation and degeneration in hepatocytes and the underlying molecular mechanism remain unknown. Autophagy inhibition promotes lipid accumulation and steatosis in hepatocytes. Read More

View Article and Full-Text PDF

Antihypertensive Effect of a Novel Angiotensin II Receptor Blocker Fluorophenyl Benzimidazole: Contribution of cGMP, Voltage-dependent Calcium Channels, and BK Channels to Vasorelaxant Mechanisms.

Front Pharmacol 2021 30;12:611109. Epub 2021 Mar 30.

Bioprospection and Product Development Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India.

The current study presents the novel angiotensin II receptor blocker fluorophenyl benzimidazole (FPD) as an antihypertensive agent in the SHR model of hypertension. We investigated the role of cGMP, voltage-dependent L-type calcium channels, and BK channels in the vasorelaxant mechanisms of FPD in the rat superior mesenteric artery. The antihypertensive effect of FPD was examined using an invasive technique measuring blood pressure in SHR animals. Read More

View Article and Full-Text PDF

Role of the NO-cGMP-K+ channels pathway in the peripheral antinociception induced by α-bisabolol.

Can J Physiol Pharmacol 2021 Apr 15. Epub 2021 Apr 15.

Centro de Investigaci�n y Estudios Avanzados IPN, Department of Pharmacology, Av. Instituto Polit�cnico Nacional 258. Colonia San Pedro Zacatenco, Mexico, DF, Mexico, 07360;

The aim of this study was to examine if the peripheral antinociception of α-bisabolol involve the participation of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) synthesis followed by K+ channel opening in the formalin test. Wistar rats were injected in the dorsal surface of the right hind paw with formalin (1%). Rats received a subcutaneous injection into the dorsal surface of the paw of vehicles or increasing doses of α-bisabolol (100-300 µg/paw). Read More

View Article and Full-Text PDF

An arginine residue in the outer segment of hASIC1a TM1 affects both proton affinity and channel desensitization.

J Gen Physiol 2021 May;153(5)

Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China.

Acid-sensing ion channels (ASICs) respond to changes in pH in the central and peripheral nervous systems and participate in synaptic plasticity and pain perception. Understanding the proton-mediated gating mechanism remains elusive despite the of their structures in various conformational states. We report here that R64, an arginine located in the outer segment of the first transmembrane domain of all three isoforms of mammalian ASICs, markedly impacts the apparent proton affinity of activation and the degree of desensitization from the open and preopen states. Read More

View Article and Full-Text PDF

Buprenorphine may be effective for treatment of paramyotonia congenita.

Muscle Nerve 2021 Apr 9. Epub 2021 Apr 9.

IRCCS Mondino Foundation, Pavia, Italy.

Introduction/aims: Paramyotonia congenita (PMC) is a skeletal muscle sodium channelopathy characterized by paradoxical myotonia, cold sensitivity, and exercise/cold-induced paralysis. Treatment with sodium-channel-blocking antiarrhythmic agents may expose patients to a risk of arrhythmia or may be poorly tolerated or ineffective. In this study we explored the effectiveness of non-antiarrhythmic sodium-channel blockers in two patients with PMC. Read More

View Article and Full-Text PDF

Transient opening of tricellular vertices controls paracellular transport through the follicle epithelium during Drosophila oogenesis.

Dev Cell 2021 Apr 7;56(8):1083-1099.e5. Epub 2021 Apr 7.

Institute of Animal Physiology, University of Münster, Schlossplatz 8, 48143 Münster, Germany; Cells in Motion (CiM) Interfaculty Center, 48149 Münster, Germany. Electronic address:

Paracellular permeability is regulated to allow solute transport or cell migration across epithelial or endothelial barriers. However, how cell-cell junction dynamics controls paracellular permeability is poorly understood. Here, we describe patency, a developmentally regulated process in Drosophila oogenesis, during which cell vertices in the follicular epithelium open transiently to allow paracellular transport of yolk proteins for uptake by the oocyte. Read More

View Article and Full-Text PDF

Regulation of Anion Channel LRRC8 Volume-Regulated Anion Channels in Transport of 2'3'-Cyclic GMP-AMP and Cisplatin under Steady State and Inflammation.

J Immunol 2021 May 7;206(9):2061-2074. Epub 2021 Apr 7.

The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China;

The recently identified anion channel LRRC8 volume-regulated anion channels (VRACs) are heteromeric hexamers constituted with the obligate LRRC8A subunit paired with at least one of the accessory LRRC8B to LRRC8E subunits. In addition to transport chloride, taurine, and glutamate, LRRC8 VRACs also transport the anticancer agent cisplatin and STING agonists 2'3'-cyclic GMP-AMP (cGAMP) and cyclic dinucleotides; hence, they are implicated in a variety of physiological and pathological processes, such as cell swelling, stroke, cancer, and viral infection. Although the subunit composition largely determines VRAC substrate specificity, the opening of various VRAC pores under physiological and pathological settings remains enigmatic. Read More

View Article and Full-Text PDF

Kir4.1/Kir5.1 channels possess strong intrinsic inward rectification determined by a voltage-dependent K+-flux gating mechanism.

J Gen Physiol 2021 May;153(5)

Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, México.

Inwardly rectifying potassium (Kir) channels are broadly expressed in both excitable and nonexcitable tissues, where they contribute to a wide variety of cellular functions. Numerous studies have established that rectification of Kir channels is not an inherent property of the channel protein itself, but rather reflects strong voltage dependence of channel block by intracellular cations, such as polyamines and Mg2+. Here, we identify a previously unknown mechanism of inward rectification in Kir4. Read More

View Article and Full-Text PDF

Unmasking coupling between channel gating and ion permeation in the muscle nicotinic receptor.

Elife 2021 04 6;10. Epub 2021 Apr 6.

Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Rochester, United States.

Whether ion channel gating is independent of ion permeation has been an enduring, unresolved question. Here, applying single channel recording to the archetypal muscle nicotinic receptor, we unmask coupling between channel gating and ion permeation by structural perturbation of a conserved intramembrane salt bridge. A charge-neutralizing mutation suppresses channel gating, reduces unitary current amplitude, and increases fluctuations of the open channel current. Read More

View Article and Full-Text PDF

Optimization of Structure and Electrical Characteristics for Four-Layer Vertically-Stacked Horizontal Gate-All-Around Si Nanosheets Devices.

Nanomaterials (Basel) 2021 Mar 5;11(3). Epub 2021 Mar 5.

Advanced Integrated Circuits R&D Center, Institute of Microelectronic of the Chinese Academy of Sciences, Beijing 100029, China.

In this paper, the optimizations of vertically-stacked horizontal gate-all-around (GAA) Si nanosheet (NS) transistors on bulk Si substrate are systemically investigated. The release process of NS channels was firstly optimized to achieve uniform device structures. An over 100:1 selective wet-etch ratio of GeSi to Si layer was achieved for GeSi/Si stacks samples with different GeSi thickness (5 nm, 10 nm, and 20 nm) or annealing temperatures (≤900 °C). Read More

View Article and Full-Text PDF

Design and Simulation of Air-Breathing Micro Direct Methanol Fuel Cells with Different Anode Flow Fields.

Micromachines (Basel) 2021 Mar 2;12(3). Epub 2021 Mar 2.

MEMS Center, Harbin Institute of Technology, Harbin 150001, China.

The design of the anode flow field is critical for yielding better performance of micro direct methanol fuel cells (µDMFCs). In this work, the effect of different flow fields on cell performance was investigated by the simulation method. Compared with grid, parallel and double-serpentine flow fields, a single-serpentine flow field can better improve the mass transfer efficiency of methanol and the emission efficiency of the carbon dioxide by-product. Read More

View Article and Full-Text PDF

An XROMM Study of Food Transport and Swallowing in Channel Catfish.

Integr Org Biol 2020 19;2(1):obaa018. Epub 2020 Jun 19.

Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA.

Most predatory ray-finned fishes swallow their food whole, which can pose a significant challenge, given that prey items can be half as large as the predators themselves. How do fish transport captured food from the mouth to the stomach? Prior work indicates that, in general, fish use the pharyngeal jaws to manipulate food into the esophagus, where peristalsis is thought to take over. We used X-Ray Reconstruction of Moving Morphology to track prey transport in channel catfish (). Read More

View Article and Full-Text PDF

Transmission at rod and cone ribbon synapses in the retina.

Pflugers Arch 2021 Mar 29. Epub 2021 Mar 29.

Truhlsen Eye Institute, Departments of Ophthalmology & Visual Sciences and Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, 68198, USA.

Light-evoked voltage responses of rod and cone photoreceptor cells in the vertebrate retina must be converted to a train of synaptic vesicle release events for transmission to downstream neurons. This review discusses the processes, proteins, and structures that shape this critical early step in vision, focusing on studies from salamander retina with comparisons to other experimental animals. Many mechanisms are conserved across species. Read More

View Article and Full-Text PDF

Opening of ATP sensitive potassium channels causes migraine attacks with aura.

Brain 2021 Mar 26. Epub 2021 Mar 26.

Danish Headache Center, Dept. of Neurology, Rigshospitalet Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.

Migraine afflicts more than one billion individuals worldwide and is a leading cause of years lived with disability. In about a third of individuals with migraine aura occur in relation to migraine headache. The common pathophysiological mechanisms underlying migraine headache and migraine aura are yet to be identified. Read More

View Article and Full-Text PDF

Electrochemical assessments of droplet contents in microfluidic channels. Application to the titration of heterogeneous droplets.

Anal Chim Acta 2021 Apr 20;1155:338344. Epub 2021 Feb 20.

PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France. Electronic address:

Series of aqueous droplets containing redox species were generated on-demand in a microfluidic channel and detected downstream by an electrochemical cell. Depending on the cell geometry, amperometric detections were performed to simultaneously determine the velocity, volume and content of circulating droplets in oil. Volumes and velocities were estimated from specific transition times on the chronoamperometric responses, while charge were evaluated from current integration. Read More

View Article and Full-Text PDF

A new species of the genus Fredius Pretzmann, 1967 (Decapoda: Brachyura: Pseudothelphusidae) from Brazil, with comments on the southerly distribution of the family.

Zootaxa 2021 Jan 7;4903(2):zootaxa.4903.2.8. Epub 2021 Jan 7.

Laboratório de Crustáceos do Semiárido (LACRUSE), Departamento de Ciências e Biológicas, Universidade Regional do Cariri, URCA. 63100-000, Crato, Ceará, Brazil..

A new species of pseudothelphusid crab of the tribe Kingsleyini Ortmann, 1897, from the southern Amazon region in the state of Rondônia, Brazil, is described and illustrated. Fredius avilai n. sp. Read More

View Article and Full-Text PDF
January 2021

Time-resolved serial femtosecond crystallography reveals early structural changes in channelrhodopsin.

Elife 2021 03 23;10. Epub 2021 Mar 23.

Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.

Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled with channel opening and closing. However, the detailed molecular events underlying channel gating remain unknown. Read More

View Article and Full-Text PDF

Recognition of acute lymphoblastic leukemia and lymphocytes cell subtypes in microscopic images using random forest classifier.

Phys Eng Sci Med 2021 Mar 22. Epub 2021 Mar 22.

Department of Biomedical Engineering and Medical Physics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Acute lymphoblastic leukemia (ALL) is the most frequently leukemia and categorized into three morphological subtypes named L1, L2 and L3. Early diagnosis of ALL plays a key role in treatment procedure especially in the case of children. Several similarities between morphology of three subtypes ALL (L1, L2, L3) and lymphocyte subtypes (normal, reactive and atypical) as noncancerous cells have remained a high challenge. Read More

View Article and Full-Text PDF

Quantum key distribution with entangled photons generated on demand by a quantum dot.

Sci Adv 2021 Mar 19;7(12). Epub 2021 Mar 19.

Department of Physics, Sapienza University of Rome, 00185 Rome, Italy.

Quantum key distribution-exchanging a random secret key relying on a quantum mechanical resource-is the core feature of secure quantum networks. Entanglement-based protocols offer additional layers of security and scale favorably with quantum repeaters, but the stringent requirements set on the photon source have made their use situational so far. Semiconductor-based quantum emitters are a promising solution in this scenario, ensuring on-demand generation of near-unity-fidelity entangled photons with record-low multiphoton emission, the latter feature countering some of the best eavesdropping attacks. Read More

View Article and Full-Text PDF

Structure and gating mechanism of the α7 nicotinic acetylcholine receptor.

Cell 2021 Apr 17;184(8):2121-2134.e13. Epub 2021 Mar 17.

Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address:

The α7 nicotinic acetylcholine receptor plays critical roles in the central nervous system and in the cholinergic inflammatory pathway. This ligand-gated ion channel assembles as a homopentamer, is exceptionally permeable to Ca, and desensitizes faster than any other Cys-loop receptor. The α7 receptor has served as a prototype for the Cys-loop superfamily yet has proven refractory to structural analysis. Read More

View Article and Full-Text PDF

Single WTe Sheet-Based Electrocatalytic Microdevice for Directly Detecting Enhanced Activity of Doped Electronegative Anions.

ACS Appl Mater Interfaces 2021 Mar 18;13(12):14302-14311. Epub 2021 Mar 18.

State Key Laboratory of Materials Processing and Die & Mould Technology, and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.

The high electrical conductivity of 1T'-WTe deserves particular attention and may show a high potential for hydrogen evolution reaction (HER) catalysis. However, the actual activity certainly does not match expectations, and the inferior HER activity is actually still ambiguous at the atomic level. Unraveling the underlying HER behaviors of 1T'-WTe will give rise to a new family of HER catalysts. Read More

View Article and Full-Text PDF

TRPM3 in Brain (Patho)Physiology.

Front Cell Dev Biol 2021 26;9:635659. Epub 2021 Feb 26.

Laboratory of Cellular and Molecular Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.

Already for centuries, humankind is driven to understand the physiological and pathological mechanisms that occur in our brains. Today, we know that ion channels play an essential role in the regulation of neural processes and control many functions of the central nervous system. Ion channels present a diverse group of membrane-spanning proteins that allow ions to penetrate the insulating cell membrane upon opening of their channel pores. Read More

View Article and Full-Text PDF
February 2021

Deciphering the structure, function, expression and regulation of aquaporin-5 in cancer evolution.

Oncol Lett 2021 Apr 21;21(4):309. Epub 2021 Feb 21.

Department of Respiratory, Weifang People's Hospital, Weifang, Shandong 261000, P.R. China.

In recent years, the morbidity rate resulting from numerous types of malignant tumor has increased annually, and the treatment of tumors has been attracting an increasing amount of attention. A number of recent studies have revealed that the water channel protein aquaporin-5 (AQP5) has become a major player in multiple types of cancer. AQP5 is abnormally expressed in a variety of tumor tissues or cells and has multiple effects on certain biological functions of tumors, such as regulating the proliferation, apoptosis and migration of tumor cells. Read More

View Article and Full-Text PDF

Proteasome in action: substrate degradation by the 26S proteasome.

Biochem Soc Trans 2021 Mar 17. Epub 2021 Mar 17.

Faculty of Biology, Technion-Israel Institute of Technology, 32000 Haifa, Israel.

Ubiquitination is the major criteria for the recognition of a substrate-protein by the 26S proteasome. Additionally, a disordered segment on the substrate - either intrinsic or induced - is critical for proteasome engagement. The proteasome is geared to interact with both of these substrate features and prepare it for degradation. Read More

View Article and Full-Text PDF

Computational analysis of the effect of KCNH2 L532P mutation on ventricular electromechanical behaviors.

J Electrocardiol 2021 Feb 14;66:24-32. Epub 2021 Feb 14.

Department of IT Convergence Engineering, Kumoh National Institute of Technology, Gumi 39177, Republic of Korea. Electronic address:

The KCNH2 L532P mutation is an alteration in the I channel that is associated with short QT syndrome and atrial fibrillation in zebrafish. In preliminary studies, the electrophysiological effects of the hERG L532P mutation were investigated using a mathematical model in a single-cell and 2D sheet medium. The objective of this study was to quantify the effects of the KCNH2 L532P mutation on the 3D ventricular electrophysiological behavior and the mechanical pumping responses. Read More

View Article and Full-Text PDF
February 2021

Working classification and the quest for an effective, reconstructive management strategy in Y duplication of male urethra.

J Pediatr Urol 2021 Feb 16. Epub 2021 Feb 16.

Department of Paediatric Surgery, PSG Institute of Medical Sciences and Research, Coimbatore, Tamilnadu, India.

Introduction: Y-duplication is a rare subtype of urethral duplication whose surgical correction has traditionally yielded less than satisfactory results. Herein we report 18 patients, 17 of whom have completed successful urethral reconstruction.

Materials And Methods: A retrospective analysis was done on 18 children who have undergone repair of Y-duplication urethra in two tertiary care institutes from 2013 to 2020. Read More

View Article and Full-Text PDF
February 2021

Channelrhodopsin C1C2: Photocycle kinetics and interactions near the central gate.

Biophys J 2021 Mar 9. Epub 2021 Mar 9.

Sandia National Laboratories, Albuquerque, New Mexico. Electronic address:

Channelrhodopsins (ChR) are light-sensitive cation channels used in optogenetics, a technique that applies light to control cells (e.g., neurons) that have been modified genetically to express those channels. Read More

View Article and Full-Text PDF