The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
The voltage difference, normally maintained at approximately -180mV, across the INNER MITOCHONDRIAL MEMBRANE, by a net movement of positive charge across the membrane. It is a major component of the PROTON MOTIVE FORCE in MITOCHONDRIA used to drive the synthesis of ATP.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
The ability of a substrate to allow the passage of ELECTRONS.
A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
The two lipoprotein layers in the MITOCHONDRION. The outer membrane encloses the entire mitochondrion and contains channels with TRANSPORT PROTEINS to move molecules and ions in and out of the organelle. The inner membrane folds into cristae and contains many ENZYMES important to cell METABOLISM and energy production (MITOCHONDRIAL ATP SYNTHASE).
A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
Established cell cultures that have the potential to propagate indefinitely.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Glycoproteins found on the membrane or surface of cells.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
A proton ionophore that is commonly used as an uncoupling agent in biochemical studies.
The rate dynamics in chemical or physical systems.
Elements of limited time intervals, contributing to particular results or situations.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
A proton ionophore. It is commonly used as an uncoupling agent and inhibitor of photosynthesis because of its effects on mitochondrial and chloroplast membranes.
Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)
An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.
Transport proteins that carry specific substances in the blood or across cell membranes.
Use of electric potential or currents to elicit biological responses.
One of the mechanisms by which CELL DEATH occurs (compare with NECROSIS and AUTOPHAGOCYTOSIS). Apoptosis is the mechanism responsible for the physiological deletion of cells and appears to be intrinsically programmed. It is characterized by distinctive morphologic changes in the nucleus and cytoplasm, chromatin cleavage at regularly spaced sites, and the endonucleolytic cleavage of genomic DNA; (DNA FRAGMENTATION); at internucleosomal sites. This mode of cell death serves as a balance to mitosis in regulating the size of animal tissues and in mediating pathologic processes associated with tumor growth.
A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
Compounds that contain three methine groups. They are frequently used as cationic dyes used for differential staining of biological materials.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.
Ions with the suffix -onium, indicating cations with coordination number 4 of the type RxA+ which are analogous to QUATERNARY AMMONIUM COMPOUNDS (H4N+). Ions include phosphonium R4P+, oxonium R3O+, sulfonium R3S+, chloronium R2Cl+
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
A polyether antibiotic which affects ion transport and ATPase activity in mitochondria. It is produced by Streptomyces hygroscopicus. (From Merck Index, 11th ed)
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.
A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
A member of the alkali metals. It has an atomic symbol Cs, atomic number 50, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Cytochromes of the c type that are found in eukaryotic MITOCHONDRIA. They serve as redox intermediates that accept electrons from MITOCHONDRIAL ELECTRON TRANSPORT COMPLEX III and transfer them to MITOCHONDRIAL ELECTRON TRANSPORT COMPLEX IV.
Proteins involved in the transport of specific substances across the membranes of the MITOCHONDRIA.
Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)
Proteins found in any species of bacterium.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Chemical agents that increase the permeability of biological or artificial lipid membranes to specific ions. Most ionophores are relatively small organic molecules that act as mobile carriers within membranes or coalesce to form ion permeable channels across membranes. Many are antibiotics, and many act as uncoupling agents by short-circuiting the proton gradient across mitochondrial membranes.
Minute projections of cell membranes which greatly increase the surface area of the cell.
The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
The thin layers of tissue that surround the developing embryo. There are four extra-embryonic membranes commonly found in VERTEBRATES, such as REPTILES; BIRDS; and MAMMALS. They are the YOLK SAC, the ALLANTOIS, the AMNION, and the CHORION. These membranes provide protection and means to transport nutrients and wastes.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
Contractile tissue that produces movement in animals.
Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.
A closely related group of toxic substances elaborated by various strains of Streptomyces. They are 26-membered macrolides with lactone moieties and double bonds and inhibit various ATPases, causing uncoupling of phosphorylation from mitochondrial respiration. Used as tools in cytochemistry. Some specific oligomycins are RUTAMYCIN, peliomycin, and botrycidin (formerly venturicidin X).
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.
The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.
Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.
A fluorescent probe with low toxicity which is a potent substrate for P-glycoprotein and the bacterial multidrug efflux transporter. It is used to assess mitochondrial bioenergetics in living cells and to measure the efflux activity of P-glycoprotein in both normal and malignant cells. (Leukemia 1997;11(7):1124-30)
Chemical agents that uncouple oxidation from phosphorylation in the metabolic cycle so that ATP synthesis does not occur. Included here are those IONOPHORES that disrupt electron transfer by short-circuiting the proton gradient across mitochondrial membranes.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
An order of the class Amphibia, which includes several families of frogs and toads. They are characterized by well developed hind limbs adapted for jumping, fused head and trunk and webbed toes. The term "toad" is ambiguous and is properly applied only to the family Bufonidae.
Measurement of the intensity and quality of fluorescence.
The sum of the weight of all the atoms in a molecule.
A family of intracellular CYSTEINE ENDOPEPTIDASES that play a role in regulating INFLAMMATION and APOPTOSIS. They specifically cleave peptides at a CYSTEINE amino acid that follows an ASPARTIC ACID residue. Caspases are activated by proteolytic cleavage of a precursor form to yield large and small subunits that form the enzyme. Since the cleavage site within precursors matches the specificity of caspases, sequential activation of precursors by activated caspases can occur.
Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.
An element that is an alkali metal. It has an atomic symbol Rb, atomic number 37, and atomic weight 85.47. It is used as a chemical reagent and in the manufacture of photoelectric cells.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a serine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and serine and 2 moles of fatty acids.
The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
Cell membrane glycoproteins that form channels to selectively pass chloride ions. Nonselective blockers include FENAMATES; ETHACRYNIC ACID; and TAMOXIFEN.
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
Reversible chemical reaction between a solid, often one of the ION EXCHANGE RESINS, and a fluid whereby ions may be exchanged from one substance to another. This technique is used in water purification, in research, and in industry.
The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.
Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
A family of 3,6-di(substituted-amino)-9-benzoate derivatives of xanthene that are used as dyes and as indicators for various metals; also used as fluorescent tracers in histochemistry.
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
A 37-amino acid residue peptide isolated from the scorpion Leiurus quinquestriatus hebraeus. It is a neurotoxin that inhibits calcium activated potassium channels.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Proteins prepared by recombinant DNA technology.
An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
Potassium channels where the flow of K+ ions into the cell is greater than the outward flow.
The tendency of a phenomenon to recur at regular intervals; in biological systems, the recurrence of certain activities (including hormonal, cellular, neural) may be annual, seasonal, monthly, daily, or more frequently (ultradian).
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
A superorder of CEPHALOPODS comprised of squid, cuttlefish, and their relatives. Their distinguishing feature is the modification of their fourth pair of arms into tentacles, resulting in 10 limbs.
Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
Potassium channels that contain two pores in tandem. They are responsible for baseline or leak currents and may be the most numerous of all K channels.
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
An increase in MITOCHONDRIAL VOLUME due to an influx of fluid; it occurs in hypotonic solutions due to osmotic pressure and in isotonic solutions as a result of altered permeability of the membranes of respiring mitochondria.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
Functionally and structurally differentiated, purple-pigmented regions of the cytoplasmic membrane of some strains of Halobacterium halobium. The membrane develops under anaerobic conditions and is made almost entirely of the purple pigment BACTERIORHODOPSINS. (From Singleton & Sainsbury Dictionary of Microbiology and Molecular Biology, 2d ed)
A cell line derived from cultured tumor cells.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
A short pro-domain caspase that plays an effector role in APOPTOSIS. It is activated by INITIATOR CASPASES such as CASPASE 9. Isoforms of this protein exist due to multiple alternative splicing of its MESSENGER RNA.
A phylum of the kingdom Metazoa. Mollusca have soft, unsegmented bodies with an anterior head, a dorsal visceral mass, and a ventral foot. Most are encased in a protective calcareous shell. It includes the classes GASTROPODA; BIVALVIA; CEPHALOPODA; Aplacophora; Scaphopoda; Polyplacophora; and Monoplacophora.
The fluid inside CELLS.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Electron transfer through the cytochrome system liberating free energy which is transformed into high-energy phosphate bonds.
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
A group of cytochromes with covalent thioether linkages between either or both of the vinyl side chains of protoheme and the protein. (Enzyme Nomenclature, 1992, p539)
The mitochondria of the myocardium.
An element in the alkali metals family. It has the atomic symbol Li, atomic number 3, and atomic weight [6.938; 6.997]. Salts of lithium are used in treating BIPOLAR DISORDER.
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.
The measurement of frequency or oscillation changes.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A highly neurotoxic polypeptide from the venom of the honey bee (Apis mellifera). It consists of 18 amino acids with two disulfide bridges and causes hyperexcitability resulting in convulsions and respiratory paralysis.
The synapse between a neuron and a muscle.
Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
An antibiotic substance produced by Streptomyces species. It inhibits mitochondrial respiration and may deplete cellular levels of ATP. Antimycin A1 has been used as a fungicide, insecticide, and miticide. (From Merck Index, 12th ed)
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
A large subphylum of mostly marine ARTHROPODS containing over 42,000 species. They include familiar arthropods such as lobsters (NEPHROPIDAE), crabs (BRACHYURA), shrimp (PENAEIDAE), and barnacles (THORACICA).
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.
Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.
A fold of the mucous membrane of the CONJUNCTIVA in many animals. At rest, it is hidden in the medial canthus. It can extend to cover part or all of the cornea to help clean the CORNEA.
A class of chemicals derived from barbituric acid or thiobarbituric acid. Many of these are GABA MODULATORS used as HYPNOTICS AND SEDATIVES, as ANESTHETICS, or as ANTICONVULSANTS.
The inner layer of CHOROID, also called the lamina basalis choroideae, located adjacent to the RETINAL PIGMENT EPITHELIUM; (RPE) of the EYE. It is a membrane composed of the basement membranes of the choriocapillaris ENDOTHELIUM and that of the RPE. The membrane stops at the OPTIC NERVE, as does the RPE.
Proteins obtained from ESCHERICHIA COLI.
Porins are protein molecules that were originally found in the outer membrane of GRAM-NEGATIVE BACTERIA and that form multi-meric channels for the passive DIFFUSION of WATER; IONS; or other small molecules. Porins are present in bacterial CELL WALLS, as well as in plant, fungal, mammalian and other vertebrate CELL MEMBRANES and MITOCHONDRIAL MEMBRANES.
Integral membrane proteins that transport protons across a membrane. This transport can be linked to the hydrolysis of ADENOSINE TRIPHOSPHATE. What is referred to as proton pump inhibitors frequently is about POTASSIUM HYDROGEN ATPASE.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Refers to animals in the period of time just after birth.
Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.
An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.
A non-penetrating amino reagent (commonly called SITS) which acts as an inhibitor of anion transport in erythrocytes and other cells.

Automatic activity in depolarized guinea pig ventricular myocardium. Characteristics and mechanisms. (1/24936)

Membrane potential was changed uniformly in segments, 0.7-1.0 mm long, of guinea pig papillary muscles excised from the right ventricle by using extracellular polarizing current pulses applied across two electrically insulated cf preparations superfused with Tyrode's solution at maximum diastolic membrane potentials ranging from-35.2+/-7.5 (threshold) to +4.0+/-9.2 mV. The average maximum dV/dt of RAD ranged from 17.1 to 18.0 V/sec within a membrane potential range of -40 to +20 mV. Raising extracellular Ca2+ concentration [Ca2+]0 from 1.8 to 6.8 mM, or application of isoproterenol (10(-6)g/ml) enhanced the rate of RAD, but lowering [Ca2+]0 to 0.4 mM or exposure to MnCl2 (6 mM) abolished RAD. RAD were enhanced by lowering extracellular K+ concentration [K+]0 from 5.4 to 1.5 mM. RAD were suppressed in 40% of fibers by raising [K+]0 to 15.4 mM, and in all fibers by raising [K+]0 to 40.4 mM. This suppression was due to increased [K+]0 and not to K-induced depolarization because it persisted when membrane potential was held by means of a conditioning hyperpolarizing puled gradually after maximum repolarization. These observations suggest that the development of RAD in depolarized myocardium is associated with a time-dependent decrease in outward current (probably K current) and with increase in the background inward current, presumably flowing through the slow cha-nel carrying Ca or Na ions, or both.  (+info)

Effect of electrotonic potentials on pacemaker activity of canine Purkinje fibers in relation to parasystole. (2/24936)

Isolated false tendons excised form dog hearts were mounted in a three-chamber tissue bath. Isotonic sucrose solution was perfused in the central chamber to provide a region of depressed conductivity between the fiber segments in chambers 1 and 3, which were perfused with Tyrode's solution. The electrotonic influence of spontaneous or driven responses evoked in chamber 3 during the first half of the spontaneous cycle of a chamber 1 peacemaker delayed the next spontaneous discharge. This effect changed to acceleration when the chamber 3 segment fired during the second half of the spontaneous cycle. We found that subthreshold depolarizing current pulses 50-300 msec applied across the sucrose gap caused similar degrees of delay or acceleration. Furthermore, hyperpolarizing currents caused the reverse pattern. The results indicate that the discharge pattern of a parasystolic focus may be altered by the electrotonic influence of activity in the surrounding tissue. The significance of these findings is considered in relation to the mechanism of production of parasystolic rhythms.  (+info)

Effect of paracetamol (acetaminophen) on gastric ionic fluxes and potential difference in man. (3/24936)

Paracetamol has replaced aspirin as the analgesic of choice in many situations. The major reason is the damaging effect of aspirin on gastric mucosa. Alterations in gastric ionic fluxes and potential difference provide measures of aspirin-induced structural damage. We studied the effect of large doses of paracetamol (acetaminophen 2-0 g) on gastric ionic fluxes in man. In addition, the effect of 2-0 g paracetamol on gastric potential difference was compared with that of 600 mg aspirin. In contrast with salicylates, paracetamol caused no significant alteration in movement of H+ and Na+ ions over control periods. Aspirin causes a significant fall in transmucosal potential difference (PD) across gastric mucosa of 15 mv, while paracetamol cuased no significant change. Paracetamol in a dose four times that recommended does not alter gastric ionic fluxes or potential difference. These studies support choice of paracetamol as analgesic over aspirin where damage to gastric mucosa may be critical.  (+info)

Dopamine stimulates salivary duct cells in the cockroach Periplaneta americana. (4/24936)

This study examines whether the salivary duct cells of the cockroach Periplaneta americana can be stimulated by the neurotransmitters dopamine and serotonin. We have carried out digital Ca2+-imaging experiments using the Ca2+-sensitive dye fura-2 and conventional intracellular recordings from isolated salivary glands. Dopamine evokes a slow, almost tonic, and reversible dose-dependent elevation in [Ca2+]i in the duct cells. Upon stimulation with 10(-)6 mol l-1 dopamine, [Ca2+]i rises from 48+/-4 nmol l-1 to 311+/-43 nmol l-1 (mean +/- s.e.m., N=18) within 200-300 s. The dopamine-induced elevation in [Ca2+]i is absent in Ca2+-free saline and is blocked by 10(-)4 mol l-1 La3+, indicating that dopamine induces an influx of Ca2+ across the basolateral membrane of the duct cells. Stimulation with 10(-)6 mol l-1 dopamine causes the basolateral membrane to depolarize from -67+/-1 to -41+/-2 mV (N=10). This depolarization is also blocked by La3+ and is abolished when Na+ in the bath solution is reduced to 10 mmol l-1. Serotonin affects neither [Ca2+]i nor the basolateral membrane potential of the duct cells. These data indicate that the neurotransmitter dopamine, which has previously been shown to stimulate fluid secretion from the glands, also stimulates the salivary duct cells, suggesting that dopamine controls their most probable function, the modification of primary saliva.  (+info)

Trans-synaptically induced bursts in regular spiking non-pyramidal cells in deep layers of the cat motor cortex. (5/24936)

In deep layers of the cat motor cortex, we have investigated the properties of neurons displaying trans-synaptically induced bursts. In in vivo experiments, extracellularly recorded burst neurons were separated into two subtypes based on their dependence on stimulation sites, the medullary pyramid or the ventrolateral (VL) thalamic nucleus, from which bursts of 10-20 spikes were triggered. The spike amplitude attenuation and frequency adaptation during a burst were more prominent in pyramid-dependent burst neurons than in VL-dependent burst neurons. Intracellular recordings in in vivo experiments revealed that pyramid-dependent bursts emerged from a long-lasting depolarization, while each spike during a VL-dependent burst was narrow in half-width and was followed by a fast AHP, similar to fast spiking neurons. In in vitro slice experiments, intracellular recordings were obtained from neurons that displayed a burst of attenuated spikes emerging from a long-lasting depolarization, and were also obtained from fast spiking neurons. They were morphologically recovered to be multipolar cells with sparsely spiny dendrites and local axonal networks, suggesting that they are inhibitory interneurons. The multipolar neurons displaying bursts of attenuated spikes may mediate the recurrent inhibition of pyramidal tract cells.  (+info)

Low resting potential and postnatal upregulation of NMDA receptors may cause Cajal-Retzius cell death. (6/24936)

Using in situ patch-clamp techniques in rat telencephalic slices, we have followed resting potential (RP) properties and the functional expression of NMDA receptors in neocortical Cajal-Retzius (CR) cells from embryonic day 18 to postnatal day 13, the time around which these cells normally disappear. We find that throughout their lives CR cells have a relatively depolarized RP (approximately -50 mV), which can be made more hyperpolarized (approximately -70 mV) by stimulation of the Na/K pump with intracellular ATP. The NMDA receptors of CR cells are subjected to intense postnatal upregulation, but their similar properties (EC50, Hill number, sensitivity to antagonists, conductance, and kinetics) throughout development suggest that their subunit composition remains relatively homogeneous. The low RP of CR cells is within a range that allows for the relief of NMDA channels from Mg2+ blockade. Our findings are consistent with the hypothesis that CR cells may degenerate and die subsequent to uncontrolled overload of intracellular Ca2+ via NMDA receptor activation by ambient glutamate. In support of this hypothesis we have obtained evidence showing the protection of CR cells via in vivo blockade of NMDA receptors with dizocilpine.  (+info)

UCP4, a novel brain-specific mitochondrial protein that reduces membrane potential in mammalian cells. (7/24936)

Uncoupling proteins (UCPs) are a family of mitochondrial transporter proteins that have been implicated in thermoregulatory heat production and maintenance of the basal metabolic rate. We have identified and partially characterized a novel member of the human uncoupling protein family, termed uncoupling protein-4 (UCP4). Protein sequence analyses showed that UCP4 is most related to UCP3 and possesses features characteristic of mitochondrial transporter proteins. Unlike other known UCPs, UCP4 transcripts are exclusively expressed in both fetal and adult brain tissues. UCP4 maps to human chromosome 6p11.2-q12. Consistent with its potential role as an uncoupling protein, UCP4 is localized to the mitochondria and its ectopic expression in mammalian cells reduces mitochondrial membrane potential. These findings suggest that UCP4 may be involved in thermoregulatory heat production and metabolism in the brain.  (+info)

Individual subunits contribute independently to slow gating of bovine EAG potassium channels. (8/24936)

The bovine ether a go-go gene encodes a delayed rectifier potassium channel. In contrast to other delayed rectifiers, its activation kinetics is largely determined by the holding potential and the concentration of extracellular Mg2+, giving rise to slowly activating currents with a characteristic sigmoidal rising phase. Replacement of a single amino acid in the extracellular linker between transmembrane segments S3 and S4 (L322H) strongly reduced the prepulse dependence and accelerated activation by 1 order of magnitude. In addition, compared with the wild type, the half-activation voltage of this mutant was shifted by more than 30 mV to more negative potentials. We used dimeric and tetrameric constructs of the bovine eag1 gene to analyze channels with defined stoichiometry of mutated and wild-type subunits within the tetrameric channel complexes. With increasing numbers of mutated subunits, the channel activation was progressively accelerated, and the sigmoidicity of the current traces was reduced. Based on a quantitative analysis, we show that the slow gating, typical for EAG channels, is mediated by independent conformational transitions of individual subunits, which gain their voltage dependence from the S4 segment. At a given voltage, external Mg2+ increases the probability of a channel subunit to be in the slowly activating conformation, whereas mutation L322H strongly reduces this probability.  (+info)

purpose. Tetraphenylphosphonium (TPP+) is a permeant lipophilic cation that accumulates in cultured cells and tissues as a function of the electrical membrane potential across the plasma membrane. This study was undertaken to determine whether TPP+ can be used for assessing membrane potential in intact lenses in organ culture.. methods. Rat lenses were cultured in media containing 10 μM TPP+ and a tracer level of 3H-TPP+ for various times. 3H-TPP+ levels in whole lenses or dissected portions of lenses were determined by liquid scintillation counting. Ionophores, transport inhibitors, and neurotransmitters were also added to investigate their effects on TPP+ uptake.. results. Incubation of lenses in low-K+ balanced salt solution and TC-199 medium, containing physiological concentrations of Na+ and K+, led to a biphasic accumulation of TPP+ in the lens that approached equilibrium by 12 to 16 hours of culture. The TPP+ equilibrated within 1 hour in the epithelium but penetrated more slowly into ...
Ceballos, Cesar C., Antonio C. Roque, and Ricardo M. Leão. A negative slope conductance of the persistent sodium current prolongs subthreshold depolarizations. Biophysical journal 113.10 (2017): 2207-2217.
TY - JOUR. T1 - Sex differences in membrane potential in the intact perfused rat liver. AU - Weisiger, R. A.. AU - Fitz, J. G.. PY - 1988. Y1 - 1988. N2 - The electrical potential difference across the plasma membrane was compared in paired livers from male and female rats perfused single-pass with Krebs-bicarbonate buffer. Variability in the membrane potential measured for different cells within the same liver was small (SD = 1.3 mV). The mean membrane potential was 5.1 mV more negative for male livers than for female livers (-30.3 ± 0.6 vs. -25.2 ± 1.0 mV, P , 0.001), and the female liver in all nine pairs studied. No correlation between membrane potential and perfusion rate was seen. Variability among female livers was more than twice as great (range -19.6 to -30.0 mV) as for male livers (range -26.7 to -31.9 mV). These results suggest that hepatic membrane potential may be modulated by sex hormone levels, which are more variable in female animals. Because the hepatic uptake of bile acids ...
can be generated along the axon while the threshold potential is reached. The greater the strength of the stimulus, causing the membrane depolarisation process to occur. Subsequently, some [[Sodium_voltage-gated_ion_channels,voltage-gated Na,sup,+,/sup, channels]] are opened, allowing the [[Sodium,Na,sup,+,/sup,]] ions to move across the membrane into the intracellular environment. The neuronal membrane now becomes slightly positive, relative to the outside of membrane. As the membrane potential shift from -70 mV to more positive value, the threshold potential is reached, causing all of the voltage-gated Na+ channel to open, creating a rapid rise of membrane potential value into the maximum, +60 mV. During depolarisation, the membrane potential value would not exceed the amount of +60mV as it is the equilibrium potential of Na,sup,+,/sup, ,ref,,/ref ...
Peak current‐voltage relationships for ICa,L in fetal ventricular cardiomyocytes. WT calmodulin data are repeated in each panel for clarity of presentation. N
Electrical activity of enzymatically isolated, smooth muscle cells from hog carotid arteries was recorded under current clamp and voltage clamp. Under the experimental conditions, membrane potential usually was not stable, and spontaneous hyperpolarizing transients of approximately 100-msec duration were recorded. The amplitude of the transients was markedly voltage dependent and ranged from about 20 mV at a membrane potential of 0 mV to undetectable at membrane potentials negative to -60 mV. Under voltage clamp, transient outward currents displayed a similar voltage dependency. These fluctuations reflect a K+ current; they were abolished by 10 mM tetraethylammonium chloride, a K+ channel blocker, and the current fluctuations reversed direction in high extracellular K+ concentration. Modulators of intracellular Ca2+ concentration also affected electrical activity. Lowering intracellular Ca2+ concentration by addition of 10 mM EGTA to the pipette solution or suppressing sarcoplasmic reticulum ...
However, the first question before addressing this problems is whether outside binding is relevant at all. Brand[2] stated that for permeabilized cells outside binding may be ignored for high mitochondrial membrane potential. Initially, this seemed to be confirmed by our own initial sensitivity studies. Using outside binding correction factors similar to the inside ones and using protein content as marker, changing the outside binding correction factor by several hundred percent caused comparable small changes in reasonable high membrane potentials and negligible changes in delta delta Psi values for permeabilized cells. However, with growing experience it became evident that unspecific binding may be underestimated by this approach, resulting in obviously too high membrane potentials especially for states of known low potential. Part of the unreasonable high membrane potential could be explained by wrong assumptions for the amount of mitochondrial protein (Pmt). Non the less, modeling of the ...
Short muscle fibers (less than 1.5 mm) from the m. lumbricalis IV digiti of Rana pipiens were voltage-clamped at -100 mV with a two-microelectrode technique, in normal Ringers solution containing 10(-6) g/ml tetrodotoxin. The activation curve relating peak tension to membrane potential could be shifted toward more negative or less negative potential values by hyperpolarizing or depolarizing the fiber membrane to -130, -120, or -70 mV, respectively, which indicates that contractile threshold depends on the fiber membrane potential. Long (greater than 5 s) depolarizing (90 mV) pulses induce prolonged contractile responses showing a plateau and a rapid relaxation phase similar to K contractures. Conditioning hyperpolarizations prolong the time course of these responses, while conditioning depolarizations shorten it. The shortening of the response time course, which results in a decrease of the area under the response, is dependent on the amplitude and duration of the conditioning depolarization. ...
In rat mesenteric arteries, the ability of ACh to evoke hyperpolarization of smooth muscle cells and consummate dilatation relies on an increase in endothelial cell cytosolic free [Ca2+] and activation of Ca2+-activated K+ channels (KCa). The time course of average and spatially organized rises in endothelial cell [Ca2+]i and concomitant effects on membrane potential were investigated in individual cells of pressurized arteries and isolated sheets of native cells stimulated with ACh. In both cases, ACh stimulated a sustained and oscillating rise in endothelial cell [Ca2+]i. Overall, the oscillations remained asynchronous between cells, yet occasionally localized intercellular coordination became evident. In pressurized arteries, repetitive waves of Ca2+ moved longitudinally across endothelial cells, and depended on Ca2+-store refilling. The rise in endothelial cell Ca2+ was associated with sustained hyperpolarization of endothelial cells in both preparations. This hyperpolarization was also evident when
Coupled interactions among solute diffusions, membrane surface potentials, and opposing enzyme reactions as a mechanism for active transports performed with biomimetic membranes
It plots for me Hodgkin-Huxley activation and inactivation curves. A little explanation: The Hodgkin-Huxley formalism is a way to describe how neurons transmit signals. Neurons transmit signals by electric impulses. There is always a voltage difference between the interior and the exterior of the cell(called membrane potential). If i change this potential somewhere, this temporary change will spread across the cells surface, like a wave. The mechanisms responsible for this process are molecules in the cell membrane(called ion channels), which can open to let ions flow trough, which causes change in the membrane potential. There are tons of different ion channels, but most of them can be described with the Hodgkin-Huxley formalism. These curves describe how much will be these channels open ( 0-closed; 1-fully open) at different membrane potential values. To make things more complicated each ion channel is modeled by 2 curves (activation and inactivation) and the product at a current membrane ...
It plots for me Hodgkin-Huxley activation and inactivation curves. A little explanation: The Hodgkin-Huxley formalism is a way to describe how neurons transmit signals. Neurons transmit signals by electric impulses. There is always a voltage difference between the interior and the exterior of the cell(called membrane potential). If i change this potential somewhere, this temporary change will spread across the cells surface, like a wave. The mechanisms responsible for this process are molecules in the cell membrane(called ion channels), which can open to let ions flow trough, which causes change in the membrane potential. There are tons of different ion channels, but most of them can be described with the Hodgkin-Huxley formalism. These curves describe how much will be these channels open ( 0-closed; 1-fully open) at different membrane potential values. To make things more complicated each ion channel is modeled by 2 curves (activation and inactivation) and the product at a current membrane ...
The modeling of particle transport involves anomalous diffusion, (x²(t) ) ∝ t{sup α} with α ≠ 1, with subdiffusive transport corresponding to 0 , α , 1 and superdiffusive transport to α , 1. These anomalies give rise to fractional advection-dispersion equations with memory in space and time. The usual Boltzmann equation, with only isolated binary collisions, is Markovian and, in particular, the contributions of the three-particle distribution function are neglected. We show that the inclusion of higher-order distribution functions give rise to an exact, non-Markovian Boltzmann equation with resulting transport equations for mass, momentum, and kinetic energy with memory in both time and space. The two- and the three-particle distribution functions are considered under the assumption that the two- and the three-particle correlation functions are translationally invariant that allows us to obtain advection-dispersion equations for modeling transport in terms of spatial and temporal ...
In the voltageclamp configuration, a current is injected into the cell via a negative feedback loop to compensate changes in membrane potential. This technique is the refinement of the voltage clamp. Neuroscience is available from oxford university press. Sep 29, 20 this screencast describes iv and vi relations derived from patch or current clamp data, and how to calculate conductance or resistance from the data. Still more recently, a technique has been invented, patch clamping, that makes it possible to voltage clamp small regions of the nerve cell membrane, and look at the responses of individual ion channels to changes in voltage across the membrane. Oct 28, 20 the voltage clamp is a technique used to control the voltage across the membrane of a small or isopotential area of a nerve cell by an electronic feedback circuit. Alternatively, the current clamp technique can be used. Identification and regulation of wholecell chloride currents. Theory the basis of the voltage clamp may be ...
1. A method is described that enables the calculation of resting membrane potential from the electrolyte and water contents in blood plasma and in a sample of human muscle tissue obtained by the percutaneous needle-biopsy technique. In this calculation, the previously described equations for calculating resting membrane potential via the intra- and extra-cellular distribution of chloride were combined with the equation utilizing potassium distribution over the cell membrane.. 2. The method of calculation was applied to 60 healthy subjects divided into three groups aged 19-40, 41-60 and 61-85 years. The calculated resting membrane potential in the subjects as a whole was −88.4 mV (SD 1.35; n = 60). A lower value was observed in the group aged 61-85 years (−87.7 mV, SD 1.0; n = 12) than in the group aged 19-40 years (−88.6 mV; SD 1.4; n = 32). No difference was observed between female and male subjects.. 3. The RMP calculated with the present method in 60 healthy subjects was also compared ...
Under the voltage clamp condition, the K inactivation was analyzed in cells bathed in the isosmotic KCl Lophius-Ringer solution. After conditioning hyperpolarization, the cells respond to depolarizations with increased K permeability, which in turn is decreased during maintained depolarizations. The steady-state levels of the K inactivation as a function of the membrane potential are related by an S-shaped curve similar to that which describes the steady-state Na inactivation in the squid giant axon. TEA reduced the K conductance by a factor which is independent of the potential, and without a shift of the inactivation curve along the voltage axis. The rapid phase of the K activation is less susceptible to TEA than the slow phase of the K activation. Hyperpolarizing steps remove the K inactivation, the rate of the removal being faster the larger the hyperpolarization from the standard potential of about -60 mv.. ...
But this polarity is not static; it is actually a very tenuous thing. With respect to which, it is of utmost importance to realize that this polarity is not the result of the asymmetry or lopsideness of the arrangement of its atoms (if that was the case then its polarity really would be static--this being the biggest mistake conventional theorists are making). Rather this polarity is the result of the asymmetry or lopsideness of its electrical gradients, what I refer to hereafter as the H2O molecules intrinsic electrical gradients. And this is especially important with repect to the fact that when an H2O molecule makes hydrogen bonds with adjacent H2O molecules additional electrical gradients are brought into play from this adjacent H2O molecule. And these additional electrical gradients, what I will refer to hereafter as incidental (or you could use external rather than incidental) electrical gradients, oppose or neutralize the H2O molecules intrinsic electrical gradients. The net effect ...
Voltage-gated n-type K(V) and Ca(2+)-activated K+ [K(Ca)] channels were studied in cell-attached patches of activated human T lymphocytes. The single-channel conductance of the K(V) channel near the resting membrane potential (Vm) was 10 pS with low K+ solution in the pipette, and 33 pS with high K+ solution in the pipette. With high K+ pipette solution, the channel showed inward rectification at positive potentials. K(V) channels in cell-attached patches of T lymphocytes inactivated more slowly than K(V) channels in the whole-cell configuration. In intact cells, steady state inactivation at the resting membrane potential was incomplete, and the threshold for activation was close to Vm. This indicates that the K(V) channel is active in the physiological Vm range. An accurate, quantitative measure for Vm was obtained from the reversal potential of the K(V) current evoked by ramp stimulation in cell-attached patches, with high K+ solution in the pipette. This method yielded an average resting Vm ...
Gonadotropin Inhibitory Hormone (GnIH) expressing neurons, through projections and interactions with gonadotropin releasing hormone (GnRH)-expressing and POMC-expressing neurons in the arcuate nucleus of the hypothalamus are suggested to serve as a fulcrum for neuroendocrine regulation of reproduction and appetite. Relatively little is known of the intrinsic membrane and extrinsic synaptic mechanisms regulating activity of GnIH neurons. Here, using the whole-cell patch clamp technique, the electrophysiological and pharmacological profile of GFP-labelled GnIH neurons has been investigated in rats in vitro.. Whole-cell recordings were obtained from 35 GnIH-GFP expressing neurons of the rat dorsomedial hypothalamus (DMH). Passive membrane properties included a mean resting membrane potential, firing rate and input resistance of 39.3 ± 0.7 mV, 0.94 ± 0.18 Hz and 1489 ± 98 mΩ, respectively. DMH GnIH neurons expressed: a 4-AP-sensitive transient outward rectification in 91% neurons; a ...
Kretzberg J, Warzecha AK, Egelhaaf M JOURNAL OF COMPUTATIONAL NEUROSCIENCE 11 (2): 153-164 2001 The neural encoding of sensory stimuli is usually investigated for spike responses, although many neurons are known to convey information by graded membrane potential changes. We compare by model simulations how well different dynamical stimuli can be discriminated on the basis of spiking or graded responses. Although a continuously varying membrane potential contains more information than binary spike trains, we find situations where different stimuli can be better discriminated on the basis of spike responses than on the basis of graded responses. Spikes can be superior to graded membrane potential fluctuations if spikes sharpen the temporal structure of neuronal responses by amplifying fast transients of the membrane potential. Such fast membrane potential changes can be induced deterministically by the stimulus or can be due to membrane potential noise that is influenced in its statistical ...
Intracellular recordings were obtained from rat neocortical neurons in vitro. The current-voltage-relationship of the neuronal membrane was investigated using current- and single-electrode-voltage-clamp techniques. Within the potential range up to 25 mV positive to the resting membrane potential (RMP: -75 to -80 mV) the steady state slope resistance increased with depolarization (i.e. steady state inward rectification in depolarizing direction). Replacement of extracellular NaCl with an equimolar amount of choline chloride resulted in the conversion of the steady state inward rectification to an outward rectification, suggesting the presence of a voltage-dependent, persistent sodium current which generated the steady state inward rectification of these neurons. Intracellularly injected outward current pulses with just subthreshold intensities elicited a transient depolarizing potential which invariably triggered the first action potential upon an increase in current strength. ...
In this lesson I want to talk about membrane potentials and the role they play in nerve transmission.. So first - what is a membrane potential. Anytime you hear potential related to nerves - think electrical charge. So the membrane potential is just the electrical charge across a membrane. In the nerves, we have a resting potential and an action potential. This should be pretty self-explanatory. The resting potential is when nothing is happening - the nerve is just resting. Well look at this more in a minute, but know that the resting membrane potential - or the resting electrical charge is negative 70 mV - meaning its more negative on the inside than the outside. The other type we have is an Action Potential - as you can see - this is when there is an ACTION happening - so an action potential is sending a stimulus to create a response somewhere in the body. The charge in an Action Potential is more positive - well look at specifics in a minute.. So when I say the resting potential is ...
TY - JOUR. T1 - Effect of the non-linear membrane potential on the migration of ionic species in concrete. AU - Marriaga, J.L.. AU - Claisse, Peter A.. PY - 2008/11. Y1 - 2008/11. KW - Concrete. KW - Electromigration. KW - Chloride modelling. KW - Membrane potential. KW - Ion transport. U2 - 10.1016/j.electacta.2008.11.031. DO - 10.1016/j.electacta.2008.11.031. M3 - Article. VL - 54. SP - 2761. EP - 2769. JO - Electrochimica Acta. JF - Electrochimica Acta. SN - 0013-4686. IS - 10. ER - ...
TY - JOUR. T1 - Hypoxia in striatal and cortical neurones. T2 - Membrane potential and Ca2+ measurements. AU - Pisani, Antonio. AU - Calabresi, Paolo. AU - Bernardi, Giorgio. PY - 1997. Y1 - 1997. N2 - Simultaneous measurements of membrane potential and intracellular Ca2+ were used to study the effects of hypoxia on striatal and cortical neurones. Striatal neurones responded to hypoxia with a reversible membrane depolarization coupled with a transient increase in intracellular Ca2+. Thirty minutes of hypoxia caused an irreversible membrane depolarization associated with a massive raise in Ca2+ levels, leading to cell death. Conversely, cortical neurones were more resistant to O2 deprivation. Hypoxia (4-10 min) induced minimal changes in both membrane potential and Ca2+ signals. Longer periods (20-30 min) caused an initial membrane hyperpolarization followed by a large but reversible depolarization coupled with a transient increase in Ca2+ signals. These results support the hypothesis of a ...
TY - JOUR. T1 - Spike-Threshold Adaptation Predicted by Membrane Potential Dynamics In Vivo. AU - Fontaine, Bertrand. AU - Peña, José Luis. AU - Brette, Romain. N1 - Copyright: Copyright 2014 Elsevier B.V., All rights reserved.. PY - 2014/4. Y1 - 2014/4. N2 - Neurons encode information in sequences of spikes, which are triggered when their membrane potential crosses a threshold. In vivo, the spiking threshold displays large variability suggesting that threshold dynamics have a profound influence on how the combined input of a neuron is encoded in the spiking. Threshold variability could be explained by adaptation to the membrane potential. However, it could also be the case that most threshold variability reflects noise and processes other than threshold adaptation. Here, we investigated threshold variation in auditory neurons responses recorded in vivo in barn owls. We found that spike threshold is quantitatively predicted by a model in which the threshold adapts, tracking the membrane ...
The voltage across a cell membrane is known as the cell membrane potential. Cells that generally have cell membrane potentials are nerve cells that are electrically active....
View Notes - 7 Membrane Potential from KINESIOLOG 1Y03 at McMaster University. Membrane Potential Membrane Potential -1 Two Types of Ion Channels Leakage (nongated) channels always open Gated
Ang II elicited a relatively small inward current (9.7 pA on average in response to 1 μmol/L peptide). However, because of the high input resistance of the cells (0.8 to 0.9 GΩ), this current is sufficient to produce the 7- to 8-mV depolarization consistently observed in current-clamp experiments. Because the cells are slowly active at rest, a depolarization of this magnitude leads to a substantial increase in discharge rate (250% of control). The depolarization (current clamp) or inward current (voltage clamp at −40 to −55 mV) was associated with a decrease in membrane conductance. This reduction of conductance is likely due to closure of K+ channels for the following reasons: First, in the presence of 3.8 mmol/L [K+]o, the current elicited by Ang II reversed polarity very close to EK (Erev, −89 mV; Fig 8A⇑), suggesting that it was carried selectively by K+. Second, raising [K+]o to 10 mmol/L shifted the Erev of the Ang II-induced current to between −60 and −68 mV, a shift that is ...
Manual patch clamp assays: Ionic current measurements. Request a Study Outline from IPST. Whole-cell current amplitude and kinetics measurements verify the results of the interaction of a test article with a selected ionic current. (The popular hERG assay is an example of ionic current assay, saimed specifically at the well-known hERG channel.) The assay is generally used to elucidate the mechanism behind various ion-channel-related arrhythmic events, and uncover ion current inhibition, either as a primary or secondary pharmacology manifestation.. A typical patch clamp study involves a pulse protocol whereby a patched cell is held at an interpulse low enough to prevent the channels from activating/opening. Generally, activation requires a depolarization to a threshold potential. Increasing voltage pulses are applied to the cell and when the voltage applied approaches, and eventually reaches that threshold potential, the current measures across the cell increases as more and more of the ...
In short, since the 1940s a dedicated slew of people have been trying different approaches to solve that equation with a precision that is unheard of in other areas of physics and engineering. All this in the name of shielding us from harmful radiation. This is all good, but why are we having this discussion in the context of synthesis and analysis based reconstructions ? It turns out that the freaks have looked at the Linear Boltzmann Equation through **many** angles. One of these angles is to decompose the flux in some eigenfunctions of the Linear Transport Operator (they are in fact distributions). There are some completude results for 1-D but 2D or 3-D are still really unexplored and not really well understood. Anyway, what was noticed empirically is that solution fluxes always end up following a diffusion equation a few mean free path away from the boundaries or sources. Close to the boundaries or sources, the full transport solution needs those eigendistributions expansions. While you may ...
The reverse use-dependence observed with GLG-V-13 and KMC-IV-84 in the present experiments has been previously reported for methanesulfonalide class III drugs such as dofetilide (Gwilt et al., 1991;Jurkiewicz and Sanguinetti, 1993), E-4031 (Wettwer et al., 1991), d,l-sotalol (Strauss et al., 1970; Hafneret al., 1988), MK-499 (Baskin and Lynch, 1994; Krafte and Volberg, 1994) and sematilide (Krafte and Volberg, 1994). The actual mechanism(s) for reverse use-dependence is/are controversial. The earliest mechanism for reverse use-dependence of action potential duration was advanced by Hondeghem and Snyders (1990). Experimental data from their laboratory demonstrated a time- and voltage-dependent modulation of Ik with quinidine. Quinidine primarily reduced time-dependent outward potassium currents at negative membrane potentials, with blockade of outward potassium currents becoming less pronounced with depolarization (Roden et al., 1988). Later data, however, have failed to demonstrate a similar ...
The results demonstrate that dendritic NMDA spike/plateau potentials can be evoked in TC neurons by local glutamate stimulation on a single dendritic arbor. The potentials had similar electrophysiological and pharmacological properties as NMDA spike/plateau potentials in cortical pyramidal neurons (Schiller et al., 2000; Nevian et al., 2007; Major et al., 2008; Larkum et al., 2009). Weak stimulation elicited a small-amplitude, EPSP-like potential at soma that gradually grew in amplitude with increasing stimulus intensity to a threshold where a marked increase of amplitude was elicited indicating a spike-like potential. Further increase caused an elongation of the potential into a plateau that could last up to several hundred milliseconds. The spike/plateau potentials were selectively blocked by the NMDA-R antagonist CPP. The Ca2+ channel blockers Cd2+, Ni2+ and nimodipine, and the Na+ channel blocker TTX had only minor effects. Even at hyperpolarized membrane potentials (−70 mV or −65 mV), ...
Kv2.1 protein is expressed in female and male arterial myocytes, where its assumed functional role has been as a voltage-gated ion channel that, upon opening, hyperpolarizes the membrane potential of these cells to impact myocyte [Ca2+]i and myogenic tone (16). Here, we propose a model in which Kv2.1 channels have a more complex function to exert opposing actions on vascular smooth muscle. In its canonical role, the opening of conducting Kv2.1 hyperpolarizes arterial myocytes, which decreases the Po of CaV1.2 channels. This lowers [Ca2+]i, inducing relaxation. Our data indicate that Kv2.1 protein has an additional nonconducting structural role in arterial myocytes: to enhance CaV1.2 clustering and activity, thereby increasing [Ca2+]i and inducing contraction. It is paradoxical that Kv2.1 could control both relaxation and contraction in arterial smooth muscle. Notably, we find that the relative contribution of the electrical and structural roles of Kv2.1 to the control of membrane potential and ...
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1. 1. ACh dose-response curves for the radular retractor muscle of Buccinum showed maximum force and membrane depolarisation of 3.3 mV at 50 μmol 1−1 ACh. 2. 2. PCh was found to be almost a full agonist for force and induced higher membrane depolarisations than ACh while BCh was only a partial agonist of very low potency. This suggests an AChR neither muscarinic nor nicotinic in mammalian terminology. 3. 3. Neither muscarine nor nicotine had any direct agonistic effects on the muscle but pre-exposure to nicotine inhibited both force and membrane depolarisation induced by a subsequent dose of ACh. 4. 4. The specific muscarinic and nicotinic antagonists atropine, d-tubocurarine and gallamine all inhibited ACh responses in a dose-dependent manner. 5. 5. Single sucrose-gap recording showed that ACh induced a depolarisation resulting in a contracture. Double sucrose-gap voltage clamp recording showed that 10 μmol 1−1 ACh induced an inward transmembrane current of ca 2 μA. Both ACh-induced ...
All living cells display a difference in electrical potential between their cytoplasm and the extracellular space. This difference in potential across the plasma membrane, commonly referred to as membrane potential, not only constitutes a signal of life, but it also constitutes a source of energy for the translocation of many kinds of molecules in and out of the intracellular space. Changes in the membrane potential are related to a number of cellular events ranging from development to rapid electrical signaling in excitable tissues. For decades, the realm of cellular electrical activity has been limited to the action of ion channels and ionotropic ATPases and transporters. Indeed, the main molecular entities responsible for rapid signaling, such as action potentials and synaptic activity, have been identified. Yet, identification of the link between electrical activity at the plasma membrane and cell proliferation, differentiation and migration remains elusive. The quest to identify this link reached a
For a nerve cell at its resting potential, the forces acting on potassium ions (K+) are: an electrical gradient, pulling K+ inward and a chemical gradient, pushing K+ outward. Suppose a cells membrane potential shifts from -move -numb. What changes in the cells permeability to K+ or An+ could cause a shift? An+ depopulating here. So we bring An+ ions into the cell. So to do this, you change membrane permeability by adding more An+ ion channels. To fill in and label the diagram.. Tell what the flow of potassium and sodium. Label Membrane potential (NV), Resting potential, Action potential, time mess. Explain deportation. Rising potential-more An going into the cell. Falling- Undershoot= potassium ion channels are still inactivated. So they would fall below the resting potential. Graded response vs. action potential-action potential is independent of the stimulus. Graded response potential is everything below the threshold. Things to know: what the threshold is. Intervention-more in the ...
Instantaneous current-voltage relations for α1G channels. (A) Sample current records, with 5 kHz Gaussian filtering, from cell e8612. The initial step to +60
Protocols for antitachycardial pacing including biphasic stimulation administered at, or just above, the diastolic depolarization threshold potential; biphasic or conventional stimulation initiated at, or just above, the diastolic depolarization threshold potential, reduced, upon capture, to below threshold; and biphasic or conventional stimulation administered at a level set just below the diastolic depolarization threshold potential. These protocols result in reliable cardiac capture with a lower stimulation level, thereby causing less damage to the heart, extending battery life, causing less pain to the patient and having greater therapeutic effectiveness. In those protocols using biphasic cardiac pacing, a first and second stimulation phase is administered. The first stimulation phase has a predefined polarity, amplitude and duration. The second stimulation phase also has a predefined polarity, amplitude and duration. The two phases are applied sequentially. Contrary to current thought, anodal
It is present in the plasma membrane. It is powered by ATP. It keeps the concentrations of Na and K ions constant on the two side of the membrane. The pump actively move Na+ ions outside of the cell. It pumps K ions inside of the cell. It moves three Na+ out for each two K+moves inside. Thus this pump establishes resting potential across the membrane. Both ions also leak back across the membrane. But K+ move more easily back to the outside. It adds to the positive charge there. Thus membrane potential of -70mV is established ...
The first step in the generation of an action potential is to depolarize the cell by injecting current into the axon. This will partially depolarize the cell membrane, causing it to become less negative and this change in membrane potential triggers voltage gated Na+ to open. Na+ ions are now free to pass through this channel, resulting in a relatively massive influx of Na+ inside the axon. Since the membrane is now overwhelmingly permeable to Na+ the membrane potential at the top of the spike will be driven close to the Na+ Nernst potential of 55+mV. Voltage gated K+ channels also open as a response to depolarization but they only do so after the opening of the Na+ channels allowing a relatively large amount of K+ to leave the axon. As the voltage gated K+ channels open, the voltage gated Na+ channels now close preventing additional Na+ from entering the axon. So much positive charged K+ leaves the axon under these conditions that the membrane potential temporarily becomes hyperpolarized at a ...
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Cells are surrounded by a plasma membrane, which defines their extent and acts as a barrier between the cells and their external environment, for example interstitial fluid or blood plasma. The membrane, as a result of its lipid bilayer structure and specific membrane proteins, is selectively permeable (the hydrophobic interior prevents the passage of both large polar molecules and ions) and therefore will only allow certain species through. This selective permeability allows asymmetric concentrations of ions to exist between the intra- and extracellular fluids. These differences can be chemical or electrical (i.e. the difference in charge between the inside and outside). Most cells maintain a membrane potential of around 80mV relative to the surrounding fluid. The membrane potential is negative because usually cells have a net negative charge due to leakiness of potassium channels and the large size of negatively charged macromolecules such as proteins and RNA. In animal cells, passive ion ...
The FLIPR® Membrane Potential Assay Kits deliver homogenous fluorescence-based formulations for observation of real-time membrane potential changes associated with ion channel activation and ion transporter proteins. Each homogeneous assay kit utilizes a proprietary indicator dye and quencher combination to maximize ce
I agree that this is correct in the classical limit. However in the complete planck law is derived by assuming that the probability that a single mode is in a state of energy E=nhν (a state of n photons) is given by a Boltzmann distribution. Hence, the derivation does not consider any limit ...
TY - JOUR. T1 - Membrane potential resonance frequency directly influences network frequency through electrical coupling. AU - Chen, Yinbo. AU - Li, Xinping. AU - Rotstein, Horacio G.. AU - Nadim, Farzan. N1 - Funding Information: Support for this work was provided by the National Institute of Mental Health (R01-MH060605; to F. Nadim), National Institute of Neurological Disorders and Stroke (R01-NS083319; to F. Nadim), and National Science Foundation (DMS1313861; to H. G. Rotstein).. PY - 2016/10. Y1 - 2016/10. N2 - Oscillatory networks often include neurons with membrane potential resonance, exhibiting a peak in the voltage amplitude as a function of current input at a nonzero (resonance) frequency (fres). Although fres has been correlated to the network frequency (fnet) in a variety of systems, a causal relationship between the two has not been established. We examine the hypothesis that combinations of biophysical parameters that shift fres, without changing other attributes of the impedance ...
Other articles where Membrane potential is discussed: nervous system: The neuronal membrane: …neurons this potential, called the membrane potential, is between −60 and −75 millivolts (mV; or thousandths of a volt; the minus sign indicates that the inner surface is negative). When the inside of the plasma membrane has a negative charge compared to the outside, the neuron is said to be…
TY - JOUR. T1 - Low doses of ethanol have Ca2+ ionophore-like effects on apical membrane potential of in vitro Necturus antrum. AU - Rutten, Michael. AU - Moore, C. D.. PY - 1991. Y1 - 1991. N2 - The effects of low doses of luminal ethanol on the amiloride-sensitive apical membrane potential of Necturus antral mucosa were studied using conventional microelectrode techniques. Luminal ethanol (0.250-4.0% vol/vol) caused a dose-dependent hyperpolarization of the apical membrane potential (V(mc)), an increase in transepithelial resistance (R(t)) and resistance ratio (R(a)/R(b)), and a decrease in transepithelial potential (V(ms)). Luminal amiloride (100 μM) to 4% ethanol-treated antra did not cause any additional hyperpolarization of V(mc). Compared with luminal 2% ethanol-Ringer, an equivalent osmotic mannitol solution depolarized V(mc) and basolateral potential (V(cs)), decreased R(t) and R(a)/R(b), and increased V(ms). A single dose of 0.50% ethanol attenuated the effects of a second 2% ethanol ...
Several physiological mechanisms allow sensory information to be propagated in neuronal networks. According to the conventional view of signal processing, graded changes of membrane potential at the dendrite are converted into a sequence of spikes. However, in many sensory receptors and several types of mostly invertebrate neurons, graded potential changes have a direct impact on the cells output signals. The visual system of the blowfly Calliphora vicina is a good model system to study synaptic transmission in vivo during sensory stimulation. We recorded extracellularly from an identified motion-sensitive neuron while simultaneously measuring and controlling the membrane potential of individual elements of its presynaptic input ensemble. The membrane potential in the terminals of the presynaptic neuron is composed of two components, graded membrane potential changes and action potentials. To dissociate the roles of action potentials and graded potential changes in synaptic transmission we used ...
TY - JOUR. T1 - Label-free imaging of membrane potential using membrane electromotility. AU - Oh, Seungeun. AU - Fang-Yen, Christopher. AU - Choi, Wonshik. AU - Yaqoob, Zahid. AU - Fu, Dan. AU - Park, Yongkeun. AU - Dassari, Ramachandra R.. AU - Feld, Michael S.. PY - 2012/7/3. Y1 - 2012/7/3. N2 - Electrical activity may cause observable changes in a cells structure in the absence of exogenous reporter molecules. In this work, we report a low-coherence interferometric microscopy technique that can detect an optical signal correlated with the membrane potential changes in individual mammalian cells without exogenous labels. By measuring milliradian-scale phase shifts in the transmitted light, we can detect changes in the cells membrane potential. We find that the observed optical signals are due to membrane electromotility, which causes the cells to deform in response to the membrane potential changes. We demonstrate wide-field imaging of the propagation of electrical stimuli in ...
A Ba(2+)-sensitive K(+) current was studied in neurons of the suprachiasmatic nucleus (SCN) using the whole cell patch-clamp technique in acutely prepared brain slices. This Ba(2+)-sensitive K(+) current was found in approximately 90% of the SCN neurons and was uniformly distributed across the SCN. Current-clamp studies revealed that Ba(2+) (500 microM) reversibly depolarized the membrane potential by 6.7 +/- 1.3 mV (n = 22) and concomitantly Ba(2+) induced an increase in the spontaneous firing rate of 0.8 +/- 0.2 Hz (n = 12). The Ba(2+)-evoked depolarizations did not depend on firing activity or spike dependent synaptic transmission. No significant day/night difference in the hyperpolarizing contribution to the resting membrane potential of the present Ba(2+)-sensitive current was observed. Voltage-clamp experiments showed that Ba(2+) (500 microM) reduced a fast-activating, voltage-dependent K(+) current. This current was activated at levels below firing threshold and exhibited outward ...
Membrane potential oscillations can be induced in molluscan neurones under a variety of artificial conditions. In the so-called burster neurones oscillations are generated even in isolated cells. A likely mechanism for bursting involves the following ionic currents: 1. A transient inward current carried by Na+ and Ca2+. This current is responsible for the upstroke of the action potentials. 2. A delayed outward current carried by K+. This current is voltage-sensitive and is responsible for the downstroke of the action potential during the early part of the burst. It becomes progressively inactivated during the burst. Its amplitude depends on the intracellular pH. 3. A rapidly developing outward current carried by K+ which is inactivated at potentials close to action potential threshold. This current tends to hold the membrane in the hyperpolarized state and is involved in spacing the action potentials. 4. A prolonged inward current which may not inactivate. It is probably carried by both Na+ ...
The effect has been studied of various media, hormones and of amino acids on the membrane potential of rat hepatoma cells in culture measured by microelectrode impalement. Cells in Eagles minimal essential medium plus 5% serum had a value which varied daily from about 5-8 mV, inside negative. The membrane potential of rat hepatocytes was measured to be 8.7 ± 0.2mV, inside negative. The membrane potential of the hepatoma cells was decreased by insulin and increased by glucagon. Membrane potential was unaffected by change of medium to Hanks or Earles balanced salt solutions or deprivation of serum. It was, however, reduced in cells in phosphate-buffered saline and by reduction of pH. The former effect was shown to be due to the higher [Na+] of phosphat-buffered saline as opposed to the other media. Addition of alanine, glycine, serine, proline and methylaminoisobutyrate all reduced membrane potential by 2-3 mV. Smaller decreases were seen with methionine, leucine and phenylalanine, but none ...
Membrane potential plays a crucial role in many important physiological processes in bacteria. It is a component of the proton-motive force and is used to power various membrane-embedded complexes, including ATP synthase, the flagellar motor, and various small-molecule transport systems (1-5). Membrane potential has also been shown to be critical for bacterial cell division, proliferation, and signaling, and recent studies have begun to elucidate the mechanisms by which bacterial membrane potential is regulated (6-10).. Bacterial membrane potential also plays a critical role in antibiotic susceptibility, highlighting the value in identifying membrane potential-altering compounds in the quest to combat multidrug-resistant pathogens (5, 11-13). For example, carbonyl cyanide 3-chlorophenylhydrazone (CCCP), a well-known proton ionophore, increases Enterobacteriaceae susceptibility to polymyxins, while others have shown that hyperpolarizing conditions, such as those with the addition of alanine and ...
TY - THES. T1 - Studies on membrane properties of cholesterol and 3-beta modified sterol analogs. AU - Lönnfors, Max. PY - 2014. Y1 - 2014. N2 - Cholesterol (Chol) is an important lipid in cellular membranes functioning both as a membrane fluidity regulator, permeability regulator and co-factor for some membrane proteins, e.g. G-protein coupled receptors. It also participates in the formation of signaling platforms and gives the membrane more mechanical strenght to prevent osmotic lysis of the cell. The sterol structure is very conserved and already minor structural modifications can completely abolish its membrane functions. The right interaction with adjacent lipids and the preference of certain lipid structures over others are also key factors in determining the membrane properties of cholesterol. Because of the many important properties of cholesterol it is of value to understand the forces and structural properties that govern the membrane behavior of this sterol. In this thesis we have ...
Using sorting protocol based on a simple staining method for mitochondrial membrane potential we were able to isolate subclones from an established monoclonal antibody production cell line with significantly altered physiological properties. The subclone sorted for lower mitochondrial membrane potential had a faster growth rate, attained higher final cell concentrations in batch cultures, had lower glucose and glutamine uptake and lactate production rates as well as a higher specific production rate. The subclone sorted for high mitochondrial membrane potential on the other hand had a lower growth rate and final cell count, increased glucose and glutamine consumption and lactate production rates. These subclones can now be used for genomic or proteomic analysis of properties that characterise a cell line with efficient or inefficient metabolism. In addition, the method described is a valuable tool for cell line development and optimisation, offering the possibility to isolate subclones with both ...
Inwardly rectifying K+ currents were studied in cut muscle fibres from frogs using the Vaseline-gap voltage-clamp method. Both faces of the membrane were exposed to 120 mM-K+ methylsulphate solution. At small negative potentials, -10 and -21 mV, the current noise spectrum, after subtraction of a control spectrum at the zero current potential, could be fitted by a Lorentzian spectral component, usually with an additional 1/f component, where f is the frequency. At more negative potentials the 1/f component predominated. The zero frequency amplitude of the Lorentzian averaged 2.6 X 10(-24) A2 Hz-1 at -10 mV and 4.6 X 10(-24) A2 Hz-1 at -21 mV, with a mean half-power frequency, fc, of 34 Hz and 45 Hz, respectively. The time constant of the K+ current activation upon hyperpolarization agrees with that calculated from fc, and the Lorentzian disappears upon replacement of external K+ by tetraethylammonium (TEA+) or Rb+. Thus, the Lorentzian component appears to be ascribable to fluctuations ...
Similar to the NMDAR, AMPARs are excitatory ionotropic glutamatergic receptors and consist of four subunits. AMPARs mediate the majority of fast excitatory synaptic transmission in the CNS and are mostly composed of two GluA1 and two GluA2 subunits. In contrast to NMDARs, there is no obligatory subunit and there is a larger variability in receptor composition (108). Importantly, the presence of GluA2 determines crucial properties of the receptor: RNA editing of the Q/R site of the GluA2 subunit modifies the pore region of the receptor so that AMPARs containing GluA2 are impermeable to Ca2+ and show a linear current-voltage relationship (109). In contrast, AMPARs without GluA2 are Ca2+ permeable, have a larger single-channel conductance, and are inwardly rectifying, as intracellular polyamines can block the channel pore at positive membrane potentials (109, 110). Patients with anti-AMPAR encephalitis harbor antibodies against either GluA1 or GluA2 subunits, resulting in a reduction of surface ...
TY - JOUR. T1 - Calcium sparklets regulate local and global calcium in murine arterial smooth muscle. AU - Amberg, Gregory C.. AU - Navedo, Manuel F.. AU - Nieves-cintrón, Madeline. AU - Molkentin, Jeffery D.. AU - Santana, Luis F.. PY - 2007/2/15. Y1 - 2007/2/15. N2 - In arterial smooth muscle, protein kinase Cα (PKCα) coerces discrete clusters of L-type Ca2+ channels to operate in a high open probability mode, resulting in subcellular domains of nearly continual Ca2+ influx called persistent Ca2+ sparklets. Our previous work suggested that steady-state Ca2+ entry into arterial myocytes, and thus global [Ca2+]i, is regulated by Ca2+ influx through clusters of L-type Ca2+ channels operating in this persistently active mode in addition to openings of solitary channels functioning in a low-activity mode. Here, we provide the first direct evidence supporting this Ca2+ sparklet model of Ca2+ influx at a physiological membrane potential and external Ca2+ concentration. In support of this ...
Excitotoxicity due to glutamate occurs as part of the ischemic cascade and is associated with stroke[1] and diseases like amyotrophic lateral sclerosis, lathyrism, autism, some forms of mental retardation, and Alzheimers disease.[8][1] Glutamic acid has been implicated in epileptic seizures. Microinjection of glutamic acid into neurons produces spontaneous depolarisations around one second apart, and this firing pattern is similar to what is known as paroxysmal depolarizing shift in epileptic attacks. This change in the resting membrane potential at seizure foci could cause spontaneous opening of voltage-activated calcium channels, leading to glutamic acid release and further depolarization. Experimental techniques to detect glutamate in intact cells include using a genetically-engineered nanosensor.[9] The sensor is a fusion of a glutamate-binding protein and two fluorescent proteins. When glutamate binds, the fluorescence of the sensor under ultraviolet light changes by resonance between the ...
Biological cells express intracellular biomolecular information to the extracellular environment as various physical responses. We show a novel computational approach to estimate intracellular biomolecular pathways from growth cone electrophysiological responses. Previously, it was shown that cGMP signaling regulates membrane potential (MP) shifts that control the growth cone turning direction during neuronal development. We present here an integrated deterministic mathematical model and Bayesian reversed-engineering framework that enables estimation of the molecular signaling pathway from electrical recordings and considers both the system uncertainty and cell-to-cell variability. Our computational method selects the most plausible molecular pathway from multiple candidates while satisfying model simplicity and considering all possible parameter ranges. The model quantitatively reproduces MP shifts depending on cGMP levels and MP variability potential in different experimental conditions. ...
Patch clamp method was used to search for, and characterize ion channel activity which may participate in cation influx in human myeloid K562 cells. In cell-attached, outside-out and whole-cell experiments two types of voltage-insensitive Na-permeable channels were identified with different selectivities for monovalent cations, referred to as channels of high (HS) and low (LS) selectivity. The unitary conductance was similar for both channel types being 12 pS (145 mmol/l Na, 23 degrees C). The relative permeability PNa/PK estimated from the extrapolated reversal potential values were 10 and 3 for HS and LS channels, respectively. Both HS and LS channels were found to be impermeable to bivalent cations (Ca2+ or Ba2+). The activity of HS and LS channels displayed a tendency to increase with depolarization. Both channel types were not blocked by tetrodotoxin and were insensitive to amiloride in the concentration range of up to 100 mumol/l. At higher concentrations (0.1-2 mmol/l), amiloride ...
Gas - Gas - Boltzmann equation: The simple mean free path description of gas transport coefficients accounts for the major observed phenomena, but it is quantitatively unsatisfactory with respect to two major points: the values of numerical constants such as a, a′, a″, and a12 and the description of the molecular collisions that define a mean free path. Indeed, collisions remain a somewhat vague concept except when they are considered to take place between molecules modeled as hard spheres. Improvement has required a different, somewhat indirect, and more mathematical approach through a quantity called the velocity distribution function. This function describes how molecular velocities are distributed
Baseline toxicity of a selection of industrial chemicals and pharmaceuticals is determined experimentally with a new in vitro test system (Kinspec) using membrane vesicles isolated from a photosynthetic bacterium, Rhodobacter sphaeroides. This test system is selective and more sensitive than other mechanistic test systems for baseline toxicity. The only concomitantly determined mechanism is uncoupling, which can be distinguished from baseline toxicity by pH-dependent measurements. Because the tests system contains only the target site for baseline toxicants, the biological membrane, effective target site concentrations can be directly related to observed effects by combining the in vitro test with membrane-water partition experiments. No differences were found between the effective membrane concentrations of nonpolar and polar compounds, confirming the earlier hypothesis that differences in lethal body burdens are primarily caused by unequal distribution of the compounds between target and ...
Neurons in the central nervous system, and in the cortex in particular, are subject to a barrage of pulses from their presynaptic populations. These synaptic pulses are mediated by conductance changes and therefore lead to increases or decreases of the neuronal membrane potential with amplitudes that are dependent on the voltage: synaptic noise is multiplicative. The statistics of the membrane potential are of experimental interest because the measurement of a single subthreshold voltage can be used to probe the activity occurring across the presynaptic population. Though the interpulse interval is not always significantly smaller than the characteristic decay time of the pulses, and so the fluctuations have the nature of shot noise, the majority of results available in the literature have been calculated in the diffusion limit, which is valid for high-rate pulses. Here the effects that multiplicative conductance noise and shot noise have on the voltage fluctuations are examined. It is shown that both
Rien, D., Kern, R., & Kurtz, R. (2011). Synaptic transmission of graded membrane potential changes and spikes between identified visual interneurons. European Journal of Neuroscience, 34(5), 705-716. doi:10.1111/j.1460-9568.2011.07801. ...
If we shift our focus over to the cardiac myocyte in particular well remember that potassium and sodium are the major role players. Potassium is concentrated intracellularly and sodium is hanging out extracellularly. The good old Sodium-Potassium pump is keeping the peace, the peace being a negative resting membrane potential. The concentration gradient across this membrane plays an important role in maintaining this action potential. As the extracellular potassium concentration increases, the resting membrane potential gets less negative. This is important because the resting membrane potential (the flat part before the action potential gets going) directly impacts the number of voltage-gated sodium channels available to generate the action potential. Fewer sodium channels means slower impulse conduction and prolonged membrane depolarization. How do we see this? QRS widening, P wave prolongation, PR widening ...
In midbrain dopamine neurons in vitro, N-methyl-D-aspartate (NMDA) evokes oscillation of membrane potential and burst firing which are dependent on a ouabain-sensitive sodium pump. In the present study, we investigated the ionic dependence and pharmacological modulation of NMDA-mediated currents which might be important in burst firing. By use of patch pipettes to record membrane currents in whole-cell voltage clamps, we found that NMDA (10 microM) evoked inward currents that were significantly reduced in a low extracellular concentration of Na+ (25 mM), but not when extracellular Ca+2 was decreased from 2.5 to 0.5 mM. The current-voltage relationship for subtracted NMDA currents showed a prominent region of negative slope conductance which was absent when the slice was perfused with solution containing zero Mg++. 7-Chlorokynurenic acid, an antagonist at the nonstrychnine-sensitive glycine binding site, produced a concentration-dependent reduction in amplitude of excitatory postsynaptic currents ...
TY - JOUR. T1 - Kv2.1 channels play opposing roles in regulating membrane potential, Ca2+ channel function, and myogenic tone in arterial smooth muscle. AU - ODwyer, Samantha C.. AU - Palacio, Stephanie. AU - Matsumoto, Collin. AU - Guarina, Laura. AU - Klug, Nicholas R.. AU - Tajada, Sendoa. AU - Rosati, Barbara. AU - McKinnon, David. AU - Trimmer, James S.. AU - Santana, L. Fernando. PY - 2020/2/18. Y1 - 2020/2/18. N2 - The accepted role of the protein Kv2.1 in arterial smooth muscle cells is to form K+ channels in the sarcolemma. Opening of Kv2.1 channels causes membrane hyperpolarization, which decreases the activity of L-type CaV1.2 channels, lowering intracellular Ca2+ ([Ca2+]i) and causing smooth muscle relaxation. A limitation of this model is that it is based exclusively on data from male arterial myocytes. Here, we used a combination of electrophysiology as well as imaging approaches to investigate the role of Kv2.1 channels in male and female arterial myocytes. We confirmed that ...
This experiment deals about understanding the nature of ionic current using a voltage-current plot usually called V-I plot. It also investigates the role of linearity in ionic current behavior.
1. Action potentials recorded in the soma of R15 neurones in the abdominal ganglia of Aplysia juliana were not suppressed by selective inhibition of either Na or Ca conductance alone. It was necessary to block both conductances to suppress action potentials. 2. Membrane currents generated by step depolarizations of the soma consisted of early transient and delayed steady-state currents. The early transient current could have one or two components depending on the activating depolarization. 3. The early more rapid component had a reversal potential at +54 mV and the reversal potential changed with extracellular Na concentration in accord with the Nernst equation. It was blocked by substitution of impermeant cations for Na, by TTX and by internal injections of Zn. It was concluded that this component was normally a Na current. 4. The later slower component of the transient current had a reversal potential at about +65 mV and the reversal potential changed with extracellular Ca concentration is accord with
Purified JC-1 Mitochondrial Membrane Potential Assay Kit from Creative Biomart. JC-1 Mitochondrial Membrane Potential Assay Kit can be used for research.
Thank you, Dr. Ferber- but let me clarify my question- Were making current clamp recordings, and injecting square current pulses whilst in current clamp. Our amplifier seems to turn off capacitance/series resistance compensation in current clamp mode, though Im not so sure. In our preparation, a strong inward rectifying current is expected to be seen in medium spiny neurons by applying hyperpolarizing pulses. Weve been applying 20 pA steps from 0 to -1nA (the maximum current injection possible for our amplifier), yet we do not see any inward rectification. Inward rectification is a defining characteristic of medium spiny neurons. These cells have been labelled iontophoretically with neurobiotin, and we see that they are indeed medium spiny neurons. Weve checked our intracellular and ACSF ionic concentrations against what others are using, and find no great difference. The cell fires what appear to be normal action potentials with depolarizing pulses in current clamp. Im thinking that ...
TY - JOUR. T1 - Self-Sustained Oscillations of Membrane Potential in DOPH-Millipore Membranes. AU - Toko, Kiyoshi. AU - Ryu, Kouichi. AU - Ezaki, Shu. AU - Yamafuji, Kaoru. PY - 1982. Y1 - 1982. N2 - Self-sustained oscillations of membrane potential in an artificial model membrane, where dioleyl phosphate (DOPH) is infiltrated into pores of a Millipore filter, are investigated both experimentally and theoretically. Spike-like selfoscillations with an extremely long period of about one hour were observed for membranes with large adsorbed amounts of DOPH in the absence of external forces such as electric current and pressure gradient. On the basis of a previously-presented model that DOPH molecules make transitions among three phases composed of oil droplets, spherical micelles and multi- or bilayer leaflets, the occurrence of self-oscillations is explained well by taking account of an accumulation and a release of salt in a pore of the filter.. AB - Self-sustained oscillations of membrane ...
MitoPedia ,abbr=mtMP, Δψ [V] ,description=The mitochondrial membrane potential, mtMP, is the electric part of the protonmotive [[force]], Δp,sub>H+,/sub>. Δψ = Δp,sub>H+,/sub> - Δµ,sub>H+,/sub> / F mtMP or Δψ is the potential difference across the inner mitochondrial (mt) membrane, expressed in the electric unit of volt [V]. Electric force of the mitochondrial membrane potential is the electric energy change per motive electron or per electron moved across the transmembrane potential difference, with the number of motive electrons expressed in the unit coulomb [C]. ,info=[[Mitchell 1961 Nature]], [[Gnaiger 2014 Preface MiP2014]] }} Communicated by [[Gnaiger E]] 2012-10-05, edited 2016-02-06, 2017-09-05. :::: The chemical part of the protonmotive force, µ,sub>H+,/sub> / F stems from the difference of pH across the mt-membrane. It contains a factor that bridges the gap between the electric force [J/C] and the chemical force [J/mol]. This ...
We have discussed simple concentration gradients-differential concentrations of a substance across a space or a membrane-but in living systems, gradients are more complex. Because ions move into and out of cells and because cells contain proteins that do not move across the membrane and are mostly negatively charged, there is also an electrical gradient, a difference of charge, across the plasma membrane. The interior of living cells is electrically negative with respect to the extracellular fluid in which they are bathed, and at the same time, cells have higher concentrations of potassium (K+) and lower concentrations of sodium (Na+) than does the extracellular fluid. So in a living cell, the concentration gradient of Na+ tends to drive it into the cell, and the electrical gradient of Na+ (a positive ion) also tends to drive it inward to the negatively charged interior. The situation is more complex, however, for other elements such as potassium. The electrical gradient of K+, a positive ion, ...
Dear Sir / Madam,. I cant patch on cardiomyocytes to record action potentials at 37 degree C using a perforated patch technique. I tried many things, but failed.. Following the suggestions from this forum, I patched the cell at room temperature. After cell got gigaohm sealed, I turned on the temperature controller. At this moment, I found that it was very easy to loss the cell, because of an electric shock?. So late on, I made a little bit changes and did as followings: (1) I turned on the temperature controller but set temperature at 22oC; (2) patched the cell to get gigaohm seal; (3) waited for about 40 minutes to allow Gramicidin to perforate the cell membrane; (4) switched voltage clmap mode to current clamp mode to see if action potential could be induced or not and (5) if the action potential could be seen, then turned the wheel of temperature controller to increase the bath temperature to 37oC at once. But I found that the cell still losed ...
View Notes - 4 Influence of Passive Membrane Properties on Neural Signals - lecture slides from IPHY 4720 at Colorado. Signaling Within & Between Nerve Cells Influence of Passive Membrane
The fundamental cellular parameters of cell volume (Vc) and resting membrane potential (Em) profoundly influence cellular, tissue, organ and whole-body physiology. Earlier work has identified a wide range of mechanisms that maintain, regulate, or otherwise influence the values of each parameter individually. However, both Vc and Em change during normal activity in skeletal muscle, and their resting values are interdependent. New quantitative theoretical and experimental techniques were developed to permit an investigation of the interrelationships between Vc and Em, in order to study the determination, maintenance and short-term regulation of each parameter in skeletal muscle. Thus a cellular model was developed that permitted accurate theoretical analysis of the influences upon both Vc and Em of the diverse mechanisms known to maintain and regulate Vc, and a laser-confocal microscope technique was developed for the dynamic measurement of Vc in viable whole-muscle preparations. These new ...
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BioAssay record AID 767820 submitted by ChEMBL: Inhibition of human ERG expressed in HEK293 cells assessed as membrane depolarization at 3 uM by patch-clamp method.
Due to commercial and government interest in devices capable of functioning in high-power, high-frequency space applications, radiation tolerant AlGaNGaN devices have been under study in recent years. Passivation of the AlGaN surface by Si3N4 prevents electron trapping and enhances the 2DEG, but it also increases gate leakage currents, which can lead to device failure. This study sought information about current leakage mechanisms by introducing displacement damage close to the Si3N4AlGaN interface. The effects of irradiation damage around the Si3N4AlGaN interface on irradiation-induced leakage current were investigated for three thicknesses of a Si3N4 passivation layer in addition to an unpassivated sample. AlGaNGaN samples were irradiated at room temperature with 15-50keV nitrogen ions. Hall measurements determined mobility and 2DEG carrier density. C-V measurements provided insight into charge location and effects of the band structure. Pre-irradiation measurements were compared to the irradiation
Na Channel Has a quick onset and quickly turns off: inactivating channel. K is the opposite with slow onset and slow turn off: noninactivating channel. This difference is caused by differences in the two proteins. The Na channel has two gates: the activation gate and the inactivation gate. The activation gate is sensitive to the potential. When the activation gate is closed the inactivation gate is closed. When the inside of the cell is depolarized, the activation gate quickly opens. The inactivation gate, composed of negative proteins, slowly is repelled by the positive change in the intracellular environment, so it closes the channel by find its way into the pore of the channel.. K Channel. Has a single gate activated by the membrane potential, so it will stay open all the time the membrane has a certain potential. Na and K Conductances Nas conductance is characterized by a rapid onset and a rapid offset. Ks conductance is characterized by a slow onset and a slow offset. Membrane potential ...
Ion channel conductance can be influenced by electrostatic effects originating from fixed surface charges that are remote from the selectivity filter. To explore whether surface charges contribute to the conductance properties of Kir2.1 channels, unitary conductance was measured in cell-attached recordings of Chinese hamster ovary (CHO) cells transfected with Kir2.1 channels over a range of K + activities (4.6-293.5 mM) using single-channel measurements as well as nonstationary fluctuation analysis for low K + activities. K + ion concentrations were shown to equilibrate across the cell membrane in our studies using the voltage-sensitive dye DiBAC 4 (5). The dependence of γ on the K + activity (a K ) was fit well by a modified Langmuir binding isotherm, with a nonzero intercept as a K approaches 0 mM, suggesting electrostatic surface charge effects. Following the addition of 100 mM N-methyl-D-glucamine (NMG + ), a nonpermeant, nonblocking cation or following pretreatment with 50 mM ...
Action potentials are used in neurons to conduct signals along the axon and occur in electrically excitable cells like neurons and cardiac muscle cells. The action potentials travel in a wave along the membrane causing the voltage sensitive channels to open to allow influx of Na+ thereby causing the conduction of the signal along the axon. The resting membrane potential of cells including neurons is -70mv. An action potential is generated by a change in the membrane potential from -70mv to +40mv when voltage gated ion channels open altering membrane permeability to Na+ and K+. ...
Complex mixtures, commonly encountered in metabolomics and food analytics, are now routinely measured by nuclear magnetic resonance (NMR) spectroscopy. Since many samples must be measured, one-dimensional proton (1D 1H) spectroscopy is the experiment of choice. A common challenge in complex mixture 1H NMR sp Lab on a Chip Recent Open Access Articles
Laboratory of Engineering Thermodynamics - University of Kaiserslautern . Laboratory of Engineering Thermodynamics (LTD) University of Kaiserslautern
We introduce and validate new computational tools that enable efficient generation and simulation of models containing stochastic ion channels distributed across dendritic and axonal membranes. Comparison of five morphologically distinct neuronal cell types reveals that when all simulated neurons contain identical densities of stochastic ion channels, the amplitude of stochastic membrane potential fluctuations differs between cell types and depends on sub-cellular location. ... The code is downloadable and more information is available at ,a href=,,/a ...
... (also transmembrane potential or membrane voltage) is the difference in electric potential between the ... the resting membrane potential is merely the membrane potential that results from the membrane permeabilities that predominate ... This term is used for the membrane potential of non-excitable cells, but also for the membrane potential of excitable cells in ... Because voltage-gated ion channels are controlled by the membrane potential, while the membrane potential itself is influenced ...
... are membrane oscillations that do not directly trigger an action potential since ... these subthreshold membrane potential oscillations do not trigger action potentials, since the firing of an action potential is ... Neurons produce action potentials when their membrane potential increases past a critical threshold. In order for neurons to ... Subthreshold membrane potential oscillations do not create an action potential; however, neurons do experience bursting when ...
Some cells or organelles have the same membrane potential throughout; neurons generally have different potentials at different ... Biological membrane potentials. The value of the signal is an electric potential (voltage). The domain is more difficult to ...
Action potential B05XA16 (WHO) Cardiopulmonary bypass Deep hypothermic circulatory arrest Membrane potential Resting potential ... "CV Physiology: Membrane Potentials". Archived from the original on 21 November 2016. Retrieved 8 November 2016. Hensley F, ... However, the removal of Na+ does not alter the resting membrane potential of the cell. Likewise, removal of extracellular Ca2+ ... Membrane inactivation gates, or h Na+ gates, are voltage dependent. The less negative the membrane voltage, the more h gates ...
... and injury potential (potential difference between injured and intact membrane/epithelium). The injury potential was, in fact, ... Oviedo, N. J; Nicolas, C. L; Adams, D. S; Levin, M (2008). "Live Imaging of Planarian Membrane Potential Using DiBAC4(3)". Cold ... Levin, M; Thorlin, T; Robinson, K. R; Nogi, T; Mercola, M (2002). "Asymmetries in H+/K+-ATPase and cell membrane potentials ... In non-excitable cells, the resting potential across the plasma membrane (Vmem) of individual cells propagate across distances ...
Pidot, A. L.; Diamond, J. M. (1964). "Streaming Potentials in a Biological Membrane". Nature. 201 (4920): 701-702. Bibcode: ... Cooke, I. M.; Diamond, J. M.; Grinnell, A. D.; Hagiwara, S.; Sakata, H. (1968). "Suppression of the action potential in nerve ... Clausen, C.; Machen, T. E.; Diamond, J. M. (1982). "Changes in the Cell Membranes of the Bullfrog Gastric Mucosa with Acid ... Loo, D. D.; Lewis, S. A.; Ifshin, M. S.; Diamond, J. M. (1983). "Turnover, membrane insertion, and degradation of sodium ...
Araya R, Jiang J, Eisenthal KB, Yuste R (November 2006). "The spine neck filters membrane potentials". Proceedings of the ... The number of ion channels on the post-synaptic membrane affects the strength of the synapse. Research suggests that the ... These processes, and by extension the number of receptors on the membrane, can be altered by synaptic activity. Experiments ... Also, these signals recruit additional receptors into the post-synaptic membrane, stimulating the production of a modified ...
Araya, R.; Jiang, J.; Eisenthal, K. B.; Yuste, R. (2006). "The spine neck filters membrane potentials". Proceedings of the ... Araya, R.; Nikolenko, V.; Eisenthal, K. B.; Yuste, R. (2007). "Sodium channels amplify spine potentials". Proceedings of the ... "Label-free probe of HIV-1 TAT peptide binding to mimetic membranes". Proceedings of the National Academy of Sciences. 111 (35 ...
July 2018). "Mitochondrial membrane potential". Analytical Biochemistry. 552: 50-59. doi:10.1016/j.ab.2017.07.009. PMC 5792320 ... This proton gradient is largely but not exclusively responsible for the mitochondrial membrane potential (ΔΨM). It allows ATP ... These levels correspond to successively more positive redox potentials, or to successively decreased potential differences ... by a high membrane potential or respiratory inhibitors such as antimycin A), Complex III may leak electrons to molecular oxygen ...
Resting Membrane Potential - Online lecture notes on the resting membrane potential The Origin of the Resting Membrane ... The relatively static membrane potential of quiescent cells is called the resting membrane potential (or resting voltage), as ... The resting membrane potential is not an equilibrium potential as it relies on the constant expenditure of energy (for ionic ... A relatively static membrane potential which is usually referred to as the ground value for trans-membrane voltage. ...
2. Membrane-potentials, apparent resistances, and mechanisms. Mechanism of the light peak and other responses originating at ... 1. Membrane-potentials, apparent resistances, and mechanisms". Journal of Neuroscience 9 (6) 1968-1976 (1989) Cited 42 times. ... "Effects of dopamine on the chick retinal-pigment epithelium - membrane-potentials and light-evoked responses". Investigative ... "Light-evoked modulation of basolateral membrane Cl− conductance in chick retinal-pigment epithelium - the light peak and fast ...
The action potential actually occurs because of the synaptic potential across the membrane of the neuron. The potential ... Excitatory post-synaptic potentials (EPSPs) depolarize the membrane and move the potential closer to the threshold for an ... Synaptic potential refers to the potential difference across the postsynaptic membrane that results from the action of ... Inhibitory postsynaptic potentials (IPSPs) hyperpolarize the membrane and move the potential farther away from the threshold, ...
As an example, the cardiac action potential illustrates how differently shaped action potentials can be generated on membranes ... is a position on the membrane, σinside and φinside are the conductivity and potential just within the membrane, and σoutside ... Thus, given these σ and φ values on the membrane, the extracellular potential φ(x) can be calculated for any position x; in ... Hodgkin AL, Huxley AF (1952). "The dual effect of membrane potential on sodium conductance in the giant axon of Loligo". J ...
Zeiger, E., W. Moody, P. Hepler and F. Varela (1977). "Light-sensitive membrane potentials in onion guard cells". Nature. 270 ( ... Hepler, P. K., S. M. Wick and S. M. Wolniak (1981). The structure and role of membranes in the mitotic apparatus. in: ... Hepler postulates that the extracellular influx of calcium is not governed by the plasma membrane but by changes in the ion- ... Wolniak, S. M., P. K. Hepler, and W. T. Jackson (1980). "Detection of the membrane-calcium distribution during mitosis in ...
See the Membrane potential article. Free radical reactions are redox reactions that occur as a part of homeostasis and killing ... The electrode potential of each half-reaction is also known as its reduction potential Eo red, or potential when the half- ... Each half-reaction has a standard electrode potential (Eo cell), which is equal to the potential difference or voltage at ... the potential difference is: Eo cell = Eo cathode - Eo anode However, the potential of the reaction at the anode is sometimes ...
Also in this purview, the source of trans-membrane potential (TMP) results due to difference of concentration of ions across ... Nicholls DG (February 2004). "Mitochondrial membrane potential and aging". Aging Cell. 3 (1): 35-40. doi:10.1111/j.1474- ... Manoj KM, Gideon DA, Parashar A (March 2021). "What is the Role of Lipid Membrane-embedded Quinones in Mitochondria and ... Manoj KM, Gideon DA, Jaeken L (March 2022). "Interaction of membrane-embedded cytochrome b-complexes with quinols: Classical Q- ...
Palmer LM, Stuart GJ (May 2009). "Membrane potential changes in dendritic spines during action potentials and synaptic input". ... It also makes possible the measurement of spatial and temporal variations in membrane potential along the surface of single ... Many physiological processes are accompanied by changes in cell membrane potential which can be detected with voltage sensitive ... Cohen LB, Salzberg BM (1978). "Optical measurement of membrane potential". Reviews of Physiology, Biochemistry and Pharmacology ...
"Membrane Potential and Action Potential". From Molecules to Networks. Elsevier. pp. 351-376. doi:10.1016/b978-0-12-397179- ... creating an action potential. Membrane transporter "Membrane Channels". Cell Biology. Elsevier. 2017. pp. 261-284. doi:10.1016/ ... A polarized membrane is a lipid membrane that has a positive electrical charge on one side and a negative charge on another ... side, which produces the resting potential in living cells. Whether or not a membrane is polarized is determined by the ...
They include diverse potentials such as receptor potentials, electrotonic potentials, subthreshold membrane potential ... This shows the temporary and reversible nature of graded potentials. Graded potentials that make the membrane potential more ... The resting membrane potential is usually around -70 mV. The typical neuron has a threshold potential ranging from -40 mV to - ... Graded potentials are changes in membrane potential that vary in size, as opposed to being all-or-none. ...
Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Postsynaptic ... If the cell is receiving two excitatory postsynaptic potentials, they combine so that the membrane potential is depolarized by ... Action potential Electrophysiology Goldman equation Membrane potential Nernst equation Neuron Neurotransmission Postsynaptic ... the combined activity of afferent neurons can cause large fluctuations in membrane potential or subthreshold membrane potential ...
Goldman DE (September 1943). "Potential, Impedance, and Rectification in Membranes". The Journal of General Physiology. 27 (1 ...
"Imaging membrane potential in dendritic spines". PNAS. 103 (3): 786-790. Bibcode:2006PNAS..103..786N. doi:10.1073/pnas. ... It has also been used to prove that backpropagating action potentials invade dendritic spines without voltage attenuation, ... which allows SH microscopy to image surface potentials without any labeling molecules. The SHG pattern is mainly determined by ...
"Mitochondrial Membrane Potential in Living Cells". Annual Review of Cell Biology. Lan Bo Chen, Andrew Murray, Rosalind A. Segal ... Chen, Lan Bo (1988-11-01). "Mitochondrial Membrane Potential in Living Cells". Annual Review of Cell Biology. 4 (1): 155-181. ...
Bernstein was also the first to introduce the Nernst equation for resting potential across the membrane. In 1907, Louis ... Bernstein's hypothesis about the action potential was confirmed by Cole and Howard Curtis, who showed that membrane conductance ... Goldman DE (September 1943). "Potential, Impedance, and Rectification in Membranes". The Journal of General Physiology. 27 (1 ... Bernstein advanced the hypothesis that the action potential resulted from a change in the permeability of the axonal membrane ...
Rhoades, Rodney A.; Bell, David R. (2012). "Plasma membrane. membrane transport, and resting membrane potential". Medical ... they are repelled by the hydrophobic sections of permeable membrane, therefore they need to be assisted by the membrane ... where the substances travel through the cell passing through both the apical membrane and basolateral membrane 2. Renal ... Facilitated diffusion is the movement of polar molecules down the concentration gradient with the assistance of membrane ...
When the membrane potential from the dendrites exceeds the resting membrane potential, a pulse is generated by the neuron cell ... If the stimulus drives the membrane to a positive potential, it is an excitatory neuron; and if it drives the resting potential ... When the cumulative postsynaptic potential exceeds the resting potential, an action potential is generated by the cell body or ... action potential). The resting potential for potassium-sodium channels in a neuron is about -65 millivolts. The membrane model ...
Ahmad, N.; Masood, A. K.; Owais, M. (15 November 2001). "Fusogenic potential of prokaryotic membrane lipids". European Journal ... he demonstrated the fusogenic attributes of sperm plasma membrane lipids, and established the prophylactic potential of ... "Fusogenic potential of sperm membrane lipids: Nature's wisdom to accomplish targeted gene delivery". FEBS Letters. 580 (9): ... Correlation with membrane-membrane fusion events. Biochim Biophys Acta. 2005 May 20;1669(2):170-81. Younus H, Owais M, Rao DN, ...
"Mitochondrial membrane potential in living cells."Annu Rev Cell Biol. 4 (1988) 155-181 Darzynkiewicz Z, Traganos F, Staiano- ... This use relies on the fact that rhodamine 123 accumulates in membranes in a manner which is dependent on membrane polarization ... Rhodamine fluorescence can also be used as a measure of membrane polarization in live cell assays both within mitochondria and ... "Mitochondrial inner membrane electrophysiology assessed by rhodamine-123 transport and fluorescence" Annals of Biomedical ...
Thus, the membrane potential affects the permeability, which then further affects the membrane potential. This sets up the ... The membrane potential goes below the resting membrane potential. Hence, there is an undershoot or hyperpolarization, termed an ... Each excitable patch of membrane has two important levels of membrane potential: the resting potential, which is the value the ... a rise in the membrane potential can cause ion channels to open, thereby causing a further rise in the membrane potential. An ...
Stämpfli, R. (1954). "A new method for measuring membrane potentials with external electrodes". Experientia. 10 (12): 508-509. ... The sucrose gap is introduced by Robert Stämpfli for the reliable measurement of action potential in nerve fibers. 10th General ...
"Factors limiting display of foreign peptides on the major coat protein of filamentous bacteriophage capsids and a potential ... Ff phages for phage display is that they require the protein of interest to be translocated across the bacterial inner membrane ...
PTGS (COX, which can be confused with "cytochrome oxidase") enzymes are monotopic membrane proteins; the membrane-binding ... Brueggemeier RW, Díaz-Cruz ES (March 2006). "Relationship between aromatase and cyclooxygenases in breast cancer: potential for ... Picot D, Loll PJ, Garavito RM (January 1994). "The X-ray crystal structure of the membrane protein prostaglandin H2 synthase-1 ... Increased expression of the PTGS2 gene in the fetal membranes is connected to the presence of inflammation, causing uterine ...
... and membrane potentials in colloidal systems. Science 112: 164-167. Clorpt History of Soil Science Pedogenesis SCORPAN Day, ... Parent material and relief define the initial state for soil development, regional climate, and potential biota determine the ... potential biota, r - relief; p - parent material; t - time. Jenny left the ellipsis open to indicate that there might be other ...
Kaplan JM, Varmus HE, Bishop JM (March 1990). "The src protein contains multiple domains for specific attachment to membranes ... Amsberg GK, Koschmieder S (2013). "Profile of bosutinib and its clinical potential in the treatment of chronic myeloid leukemia ... migration and invasive potential. So the use of a tyrosine kinase inhibitor is a possible way of reducing the progression of ... and metastatic potential of tumors. EGFR activates c-Src while EGF also increases the activity of c-Src. In addition, ...
Inwardly rectifying potassium channels, such as Kir2.6, maintain resting membrane potential in excitable cells and aid in ... Membrane protein stubs, Wikipedia articles incorporating text from the United States National Library of Medicine, Ion channels ...
"Transient Receptor Potential Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and ... Articles with short description, Short description matches Wikidata, Membrane proteins, Ion channels). ... TRPML (transient receptor potential cation channel, mucolipin subfamily) comprises a group of three evolutionarily related ... ISBN 978-94-007-0264-6. Noben-Trauth K (January 2011). "Chapter 13: TRPML3". In Islam MS (ed.). Transient Receptor Potential ...
In addition to its interactions with RNA, N forms protein-protein interactions with the coronavirus membrane protein (M) during ... and producing a strong T-cell response have led to it being studied as a potential target for coronavirus vaccines. The vaccine ... proteolysis during SARS-CoV-2 infection identifies viral cleavage sites and cellular targets with therapeutic potential". ...
There are several special leak test methods available to test the integrity of an LNG vessel's membrane cargo tanks. The ... Some scientists and local residents have raised concerns about the potential effect of Poland's underground LNG storage ...
Schnitt SJ, Fend F, Decker T (January 2022). "Breast carcinomas of low malignant potential". Virchows Archiv. 480 (1): 5-19. ... cells that normally rest on the basement membrane of mammary gland ducts and function to contract and thereby expel milk from ... Clinical-Pathologic Features and Basement Membrane Studies of 50 Cases". Pathobiology. 88 (5): 359-373. doi:10.1159/000517189. ...
This causes an ion exchange in the outer solvated layer at the glass membrane, so a change in potential is generated which can ...
This specific type of tumor appears to have a high potential for local recurrence with a high tumor bed recurrence rate during ... The cells of this tumor usually show a columnar to cuboidal cytoplasm with a well-defined cytoplasmic membrane. Vacuolated, or ... epithelial membrane antigen) → - GFAP (glial fibrillary acidic protein) → + Synaptophysin → - Chromogranin → - NSE (neuron- ...
Their main structural uses are as part of biological membranes both internal and external, such as the cell membrane. Their ... Ions are also critical for nerve and muscle function, as action potentials in these tissues are produced by the exchange of ... This is done in eukaryotes by a series of proteins in the membranes of mitochondria called the electron transport chain. In ... These proteins use the energy from reduced molecules like NADH to pump protons across a membrane. Pumping protons out of the ...
... and hence cannot usually be written in terms of a scalar potential. However, it can be written in terms of a vector potential, ... field expressed the deformation of some underlying medium-the luminiferous aether-much like the tension in a rubber membrane. ... The retarded potential formalism requires one to choose the Lorenz gauge. John Gribbin (1998). Q is for Quantum: Particle ... A set of integral equations known as retarded potentials allow one to calculate V and A from ρ and J, and from there the ...
VEGF-B treatment of hepatoma carcinoma cells can cause α-catenin to move from its normal location on the membrane into the ... Lab studies have also implicated potential therapeutic targets for future clinical studies. VEGFR-1 and EMT mediators may be ... thus enhancing the invasive potential of LNCaP cells (human prostate cancer cells). As a result, it is possible that the EMT ...
... giving the potential for 360° hearing without having to move the head. Often, the eye of the horse is looking in the same ... which is thought to equalize air pressure on the tympanic membrane. Located between the mandibles but below the occiput, it ...
RIG-G has shown the capacity to inhibit NF-κB and STAT3 signaling in lung cancer cells, which demonstrates the potential of ... such as membrane bound toll like receptors or the cytoplasmic receptors RIG-I or MDA5, can trigger release of IFNs. Toll Like ... However, the infected cell can protect neighboring cells against a potential infection of the virus by releasing interferons. ... with a system that involved the inhibition of the growth of live influenza virus in chicken embryo chorioallantoic membranes by ...
... all the hardware as well as the sorbents and membrane must be thoroughly cleaned so that any potential interference is removed ... Second, the contaminant must transport across the membrane either through the water-filled pores or through the membrane itself ... The membrane resists biofouling because the polyethersulphone used in the design is less prone than other materials. The POCIS ... The PES membrane acts as a semipermeable barrier between the sorbent and surrounding aquatic environment. It allows dissolved ...
Synovial membrane is divided into two compartments - the outer layer (subintima) and the inner layer (intima). The inner layer ... The cell-intrinsic hallmarks are: reduced apoptosis, impaired contact inhibition, increased migratory invasive potential, ... The inner lining of the joint consists of the synovium (also called the synovial membrane), a thin layer located between the ... During the progression of this disease the synovial membrane becomes a place where constant inflammatory processes take place, ...
L-arginine, a naturally occurring amino acid, has been proposed as a potential therapy for CADASIL, but as of 2017 there are no ... cause an abnormal accumulation of Notch 3 at the cytoplasmic membrane of vascular smooth muscle cells both in cerebral and ...
Lipid peroxidation of the inner mitochondrial membrane reduces the electric potential and the ability to generate energy. It is ... These processes termed oxidative stress are linked to the potential benefits of dietary polyphenol antioxidants, for example in ...
At this time, the parasite causes oral and nasal lesions causing severe damage to the mucus membranes. Visceral Leishmaniasis ... reported a skin condition that has the potential of being Leishmaniasis. It is also possible that in combination with a lack of ...
The membrane potential alters the conformation of the channel proteins, regulating their opening and closing. Cell membranes ... when a potential difference is introduced over the membrane, the associated electric field induces a conformational change in ... which are located on the inner surface of the cell membrane and do not cross the membrane, and which are coassembled with the α ... The membrane-spanning segments, designated S1-S6, all take the form of alpha helices with specialized functions. The fifth and ...
Retrieved 2013-12-04 Hygrothermal Performance and Drying Potential of Wood Frame Rainscreen Walls in Vancouver's Coastal ... building paper or air barrier membrane) that is designed to prevent water drops from passing through, but allow water vapour ...
This corresponds to a higher capacitance than a stiff membrane. A charged capacitor stores potential energy, analogously to a ... This is just as when water flow moves the rubber membrane, it increases the amount of water on one side of the membrane, and ... A capacitor is like a rubber membrane sealed inside a pipe. Water molecules cannot pass through the membrane, but some water ... The elasticity of the membrane is analogous to capacitance. A very stretchy, flexible membrane will expand more with a given ...
... which offer potential for high specific capacities and low electrochemical potentials. Unfortunately, these electrodes are ... Alan Hatton on stimuli responsive gas membranes. Broadly speaking, her work considers the design of new materials that allow ...
... for potassium in the membrane, thus the voltage across the plasma membrane is close to the Nernst potential of potassium. Even ... In order to maintain the cell membrane potential, cells keep a low concentration of sodium ions and high levels of potassium ... For instance, Na⁺/K⁺-ATPase found in the membrane of heart cells is an important target of cardiac glycosides (for example ... The Na⁺/K⁺-ATPase helps maintain resting potential, affects transport, and regulates cellular volume. It also functions as a ...
The strong immune reaction in response to exposure to the salivary protein indicates the protein's potential use in the field ... Heme acts as a toxic molecule that can generate oxygen-reactive species and bypass membranes due to its high permeability. ... The strong immune reaction in response to exposure to the salivary protein indicates the protein's potential use in the field ...
... which allows neurons to intrinsically fire action potentials at sub-threshold membrane potentials. Studies have shown that the ... Unlike the fast and transient sodium current, the persistent sodium current (INaP) is activated at very low membrane potentials ... In CS pacemakers, NE increases only the amplitude of the depolarizing drive potential and the number of action potentials ... L-type calcium channels are known to increase the frequency of action potentials in some neurons, which might be the reason ...
June 2013). "Potential roles of zinc in the pathophysiology and treatment of major depressive disorder". Neuroscience and ... protein ZIP4 was first identified as the mechanism for absorption of zinc in the gut across the basolateral membrane of the ...
Greywater has potential to cause adverse environmental effects because of concentrations of nutrients and other oxygen- ... Modern cruise ships are most commonly installed with a membrane bioreactor type treatment plant for all blackwater and ... The Convention on the Conservation of Migratory Species has identified ocean noise as a potential threat to marine life. The ...
Here, we map the electrical potentials along the membrane of di … ... A possible reason could be that channels experience nonuniform electrical potentials along the plasmalemma. ... We find that the intramembrane potential gradient is indeed more positive in the membranes of neurites than in the membranes of ... Here, we map the electrical potentials along the membrane of differentiated N1E-115 neuroblastoma cells with a potential- ...
Jia, X.; Bennett, T.D.; Cowan, M.G. Gas Permeation of Sulfur Thin-Films and Potential as a Barrier Material. Membranes 2019, 9 ... Jia, X.; Bennett, T.D.; Cowan, M.G. Gas Permeation of Sulfur Thin-Films and Potential as a Barrier Material. Membranes 2019, 9 ... and after membrane testing lasting ca. 35 days (right). Note the whitening of the aged membrane, suggestive of reversion of the ... and after membrane testing lasting ca. 35 days (right). Note the whitening of the aged membrane, suggestive of reversion of the ...
"Membrane Potential, Mitochondrial" by people in Harvard Catalyst Profiles by year, and whether "Membrane Potential, ... "Membrane Potential, Mitochondrial" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH ... Below are the most recent publications written about "Membrane Potential, Mitochondrial" by people in Profiles. ... Quantification of Myocardial Mitochondrial Membrane Potential Using PET. Curr Cardiol Rep. 2021 05 10; 23(6):70. ...
For example, the lipid bilayer is the fundamental structure of cell membranes, and the structure and dynamic of bilayer ... membranes govern the transport of materials and information in and out of cells. ... Graphene could play an important role in the modelling of cell membranes. ... Graphene shows potential for modelling cell membrane systems. (Nanowerk News) The intriguing properties of graphene-a single ...
membrane potential. violin and bow.jpg. Type. post. Author. Michael Denton. Date. October 26, 2020. Categorized. Intelligent ... membrane potential, nerve transmission, prior fitness in nature, Robert Clark, Rosalind Franklin, selective stickiness, teapot ... ATP, ATP Synthase, cell membrane, DNA, Francis Crick, Goldilocks examples, Goldilocks Zone, hydrophilic, hydrophobic, James ...
Resting membrane potential (C), membrane resistance (Rm) (D), and action potentials (E) of granule cells at DIV 10-14 were ... and membrane resistances (Rm) of granule cells at four stages are indicated. The resting membrane potential and membrane ... Resting membrane potentials (Vrest) and action potentials evoked by injecting the indicated currents for 600 ms were measured ... there was no difference in resting membrane potential or membrane resistance between granule cells cultured at 5 or 25 mm KCl ...
Characterisation of potential therapeutic molecules for neuroblastoma using chick chorioallantoic membrane xenograft model ... First, we validated the chick embryo model using retinoic acid and then investigated the potential of CDK inhibitors on ... Neuroblastoma cell lines were engrafted on the chorioallantoic membrane (CAM) of chick embryos and allowed to form tumours over ...
An optimal membrane would show minimal flux decline as time goes on. ... Fouling is an important factor to consider when selecting a membrane for any given separation process. ... Fouling Potential in Pressure Driven Membrane Processes. Fouling potential is an important factor to consider when selecting a ... Membrane fouling can easily be examined through monitoring permeate flux [of a compacted membrane], with both pressure and ...
Critical Role of Reactive Oxygen Species and Mitochondrial Membrane Potential in Korean Mistletoe Lectin-Induced Apoptosis in ... Critical Role of Reactive Oxygen Species and Mitochondrial Membrane Potential in Korean Mistletoe Lectin-Induced Apoptosis in ... Critical Role of Reactive Oxygen Species and Mitochondrial Membrane Potential in Korean Mistletoe Lectin-Induced Apoptosis in ... Critical Role of Reactive Oxygen Species and Mitochondrial Membrane Potential in Korean Mistletoe Lectin-Induced Apoptosis in ...
Hollow-fiber membrane technology: Characterization and proposed use as a potential mimic of skin vascularization towards the ... Dataset for Hollow-fiber membrane technology: Characterization and proposed use as a potential mimic of skin vascularization ...
Marhl et als 1997 model of the interrelations between calcium oscillations and ER membrane potential oscillations. ,/dc:title ... Modelling the interrelations between calcium oscillations and ER membrane potential oscillations ,/dc:title, ,bqs:volume,57,/ ... Modelling the interellations between calcium oscillations and ER membrane potential oscillations, Marko Marhl, Stefan Schuster ... Modelling the Interellations Between Calcium Oscillations and ER Membrane Potential Oscillations,/title, ,author, ,firstname, ...
After the build-up of the membrane potential, a quasi-stationary state is reached in which the pump current is compensated by a ... After the build-up of the membrane potential, a quasi-stationary state is reached in which the pump current is compensated by a ... Oxonol VI as an optical indicator for membrane potentials in lipid vesicles. Type of Publication:. Journal article. ... Oxonol VI was found to be suitable for detecting changes of membrane potential associated with the activity of the (Na+ + K+)- ...
... all affect lateral mobility of cell surface antigens in a manner consistent with a common effect on membrane potential. ... Effect of membrane potential on lateral diffusion.. J Cell Biol 1 November 1977; 75 (2): 483-489. doi: ... are altered by exposing either heterokaryons or their parent cells to conditions that change cell surface membrane potential. ...
Multichannel taste sensor using electric potential changes in lipid membranes. K. Toko, T. Matsuno, K. Yamafuji, K. Hayashi, H ... Multichannel taste sensor using electric potential changes in lipid membranes. / Toko, K.; Matsuno, T.; Yamafuji, K. et al. ... Multichannel taste sensor using electric potential changes in lipid membranes. Biosensors and Bioelectronics. 1994;9(4-5):359- ... Multichannel taste sensor using electric potential changes in lipid membranes. In: Biosensors and Bioelectronics. 1994 ; Vol. 9 ...
Membrane potential was measured (and clamped) in single isolated type I cells using the perforated-patch (amphotericin B) whole ... anoxia induced a reversible membrane depolarization (or receptor potential) accompanied, in many cases, by trains of action ... When cells were voltage clamped close to their resting potential (-40 to -60 mV), the [Ca2+]i response to anoxia was greatly ... potentials. These electrical events were coincident with a rapid rise of [Ca2+]i. ...
Walsh, G. M., Blaylock, M., & Sexton, D. (2008). Caspase activation and loss of mitochondrial membrane potential precedes ... Walsh GM, Blaylock M, Sexton D. Caspase activation and loss of mitochondrial membrane potential precedes phosphatidylserine ... Walsh, GM, Blaylock, M & Sexton, D 2008, Caspase activation and loss of mitochondrial membrane potential precedes ... T1 - Caspase activation and loss of mitochondrial membrane potential precedes phosphatidylserine exposure in CD45-dependent ...
... of pores induced by the dimerization of gramicidin molecules by monitoring changes in the membrane and action potentials of ... It forms monovalent cation-specific channel in the lipid bilayer of a cellular membrane with limited permeability to anions or ... This methodology could be used for the study of peptide interactions with neuronal cellular membranes. © 2007 IEEE. ... "The effect of gramicidin on the membrane potential of neurons in the CNS of L. stagnalis." Proceedings of the IEEE Annual ...
The membrane potentials in the hypertonic group polarized back to near normal- -78 mv-compared to no changes in the normal ... The membrane potentials in the hypertonic group polarized back to near normal- -78 mv-compared to no changes in the normal ... The membrane potentials in the hypertonic group polarized back to near normal- -78 mv-compared to no changes in the normal ... The membrane potentials in the hypertonic group polarized back to near normal- -78 mv-compared to no changes in the normal ...
Correction to: The role of microglia membrane potential in chemotaxis. Access & Citations. * 810 Article Accesses. ...
"Membrane Potentials/drug effects". Ras reduces L-type calcium channel current in cardiac myocytes. Corrective effects of L- ... To evaluate the potential effects of Ras on [Ca(2+)](i), we … ...
... mitochondrial membrane potential (MMP). Addition of ,i,N,/i,-acetylcysteine and allopurinol together caused nearly complete ... The potential molecular cytotoxic mechanisms of AZA towards isolated rat hepatocytes were investigated in this study using &# ... Mitochondrial Membrane Potential (MMP) Assay. The uptake of the cationic fluorescent dye, rhodamine 123, has been used for the ... mitochondrial membrane potential (MMP). Addition of N-acetylcysteine and allopurinol together caused nearly complete ...
Angiogenic potential of extracellular matrix of human amniotic membrane. Tissue Engineering and Regenerative Medicine, 13 ( 3 ... The ECM featured in human amniotic membrane (HAM) provides a suitable niche for the cells to adhere, grow, proliferate, migrate ... investigate the behavior of ECM components especially on the stromal side of HAM and further explore the angiogenic potential ...
Mitochondrial assessment indicated reduced inner mitochondrial membrane potential (ΔΨm) and metabolic plasticity in the SOD1- ... Zorova, L. et al. Functional significance of the mitochondrial membrane potential. Biochem. (Mosc) Suppl. Ser. A: Membr. Cell ... The mitochondrial membrane potential (ΔΨm) of diseased and WT myotubes was assessed because the ΔΨm has been shown to be vital ... Mitochondrial membrane potential assessment. Mutant and WT iPSC-derived myoblasts were plated at 50 cells/mm2 on Collagen I- ...
... by using clay material in sample as a membrane in an electrochemical cell. System includes a quick load core holder with ... to ensure no diffusion between high and low salinity brines which is critical to measure liquid/liquid junction potential (U0 ... The Membrane Potential system is designed to measure potential difference (∆U or emf) in millivolts between high and low ... The Membrane Potential system is designed to measure potential difference (∆U or emf) in millivolts between high and low ...
Smith, T. C. (1982). The use of flurescent dyes to measure membrane potentials: A response. Journal of Cellular Physiology, 112 ... Smith, Thomas C. / The use of flurescent dyes to measure membrane potentials : A response. In: Journal of Cellular Physiology. ... Smith, TC 1982, The use of flurescent dyes to measure membrane potentials: A response, Journal of Cellular Physiology, vol. ... The use of flurescent dyes to measure membrane potentials: A response. Journal of Cellular Physiology. 1982 Aug;112(2):302-305 ...
... and action potentials. Learn vocabulary, terms, and more with flashcards, games, and other study tools. ...
This plasma membrane-enriched proteome analysis created a data base of more than 500 breast cancer cell line proteins, 27% of ... Tumor-derived cell lines were used to ensure an enrichment for cancer cell-specific plasma membrane proteins because it is ... We describe here a proteomics process that comprehensively annotates the protein content of breast tumor cell membranes and ... Proteins associated with cancer cell plasma membranes are rich in known drug and antibody targets as well as other proteins ...
Kudo S, Morigaki R, Ikeda M, Oka K, Tanishita K. Effect of shear stress on mitochondrial membrane potential of cultured ... Kudo, S, Morigaki, R, Ikeda, M, Oka, K & Tanishita, K 1997, Effect of shear stress on mitochondrial membrane potential of ... Kudo, S., Morigaki, R., Ikeda, M., Oka, K., & Tanishita, K. (1997). Effect of shear stress on mitochondrial membrane potential ... Effect of shear stress on mitochondrial membrane potential of cultured endothelial cells. / Kudo, Susumu; Morigaki, Ryoma; ...
Prostate-Specific Membrane Antigen Is a Potential Antiangiogenic Target in Adrenocortical Carcinoma. Submitted by als2076 on ... Prostate-Specific Membrane Antigen Is a Potential Antiangiogenic Target in Adrenocortical Carcinoma.. ... OBJECTIVE: Assess prostate-specific membrane antigen (PSMA) expression as a potential novel therapeutic target for ACC. ... PSMA expression can be used to image ACC metastases in vivo and may be considered as a potential diagnostic and therapeutic ...
Activation of this recombinant channel, by membrane hyperpolarization, generate … ... Membrane Potentials / drug effects * Patch-Clamp Techniques * Potassium / pharmacology * Potassium Channels * Pyrimidines / ... Activation of this recombinant channel, by membrane hyperpolarization, generated a slowly activating, noninactivating inward ...
  • Membrane Potential, Mitochondrial" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (
  • The voltage difference, normally maintained at approximately -180mV, across the INNER MITOCHONDRIAL MEMBRANE, by a net movement of positive charge across the membrane. (
  • This graph shows the total number of publications written about "Membrane Potential, Mitochondrial" by people in Harvard Catalyst Profiles by year, and whether "Membrane Potential, Mitochondrial" was a major or minor topic of these publication. (
  • Below are the most recent publications written about "Membrane Potential, Mitochondrial" by people in Profiles. (
  • Quantification of Myocardial Mitochondrial Membrane Potential Using PET. (
  • Xanthine oxidase inhibition by allopurinol decreased AZA-induced cytotoxicity, ROS, and hydrogen peroxide (H 2 O 2 ) formation and increased % mitochondrial membrane potential (MMP). (
  • Mitochondrial assessment indicated reduced inner mitochondrial membrane potential (ΔΨm) and metabolic plasticity in the SOD1-iPSC derived myotubes. (
  • The mitochondria are composed of outer mitochondrial membrane, inner mitochondrial membrane, intermembrane space (space between outer and inner membrane), and matrix (space within inner mitochondrial membrane). (
  • This particular kit is designed to detect cell apoptosis by measuring the loss of the mitochondrial membrane potential (MMP). (
  • The collapse of mitochondrial membrane potential coincides with the opening of the mitochondrial permeability transition pores, leading to the release of cytochrome C into the cytosol, which in turn triggers other downstream events in the apoptotic cascade. (
  • This fluorimetric assay uses our proprietary cationic MitoLite™ Orange for the detection of the mitochondrial membrane potential change in cells. (
  • Our Cell Meter™ Orange Mitochondrial Membrane Potential Assay Kit provides all the essential components with an optimized assay method. (
  • Further mechanistic study have shown that anticancer activity of PSN-A in prostate cancer cells is associated with ROS generation, Bcl-2 family proteins modulation, mitochondrial membrane potential disruption and ultimately activation of caspase-3 and cleavage of PARP. (
  • Mitochondrial membrane potential was analyzed using JC-1 dye staining. (
  • Conversely, depletion of COX6B2 attenuates OXPHOS and collapses mitochondrial membrane potential leading to cell death or senescence. (
  • The disease is caused by mutations in the gene encoding adenylate kinase 2 (AK2), a mitochondrial protein important for regulating intracellular levels of adenosine diphosphate and maintaining mitochondrial membrane potential. (
  • MitoTracker labeling in primary neuronal and astrocytic cultures: influence of mitochondrial membrane potential and oxidants. (
  • The PQ-mediated decline of mitochondrial membrane potential or nuclear condensation were prevented by the OGG1 activators. (
  • 830 nm laser irradiation induces varicosity formation, reduces mitochondrial membrane potential and blocks fast axonal flow in small and medium diameter rat dorsal root ganglion neurons: implications for the analgesic effects of 830 nm laser. (
  • It gives an overview of membrane proteins, with particular emphasis on peripheral and integral proteins. (
  • The user will learn about membrane proteins, their structures, and how they contribute towards cell function. (
  • Comprehensive proteomic analysis of breast cancer cell membranes reveals unique proteins with potential roles in clinical cancer. (
  • Proteins associated with cancer cell plasma membranes are rich in known drug and antibody targets as well as other proteins known to play key roles in the abnormal signal transduction processes required for carcinogenesis. (
  • We describe here a proteomics process that comprehensively annotates the protein content of breast tumor cell membranes and defines the clinical relevance of such proteins. (
  • Tumor-derived cell lines were used to ensure an enrichment for cancer cell-specific plasma membrane proteins because it is difficult to purify cancer cells and then obtain good membrane preparations from clinical material. (
  • This plasma membrane-enriched proteome analysis created a data base of more than 500 breast cancer cell line proteins, 27% of which were of unknown function. (
  • The value of our approach is demonstrated by further detailed analyses of three previously uncharacterized proteins whose clinical relevance has been defined by their unique cancer expression profiles and the identification of protein-binding partners that elucidate potential functionality in cancer. (
  • The presence of negatively charged intracellular proteins, whose large molecular weight and charge mean that they are unable to cross the cell membrane. (
  • Periodontal regenerative potential of space-providing expanded polytetrafluoroethylene membranes and recombinant human bone morphogenetic proteins. (
  • The outer membrane is a smooth phospholipid bilayer, with different types of proteins imbedded in it [ 21 ]. (
  • The most important of them are the porins, which freely allow the transport (export and import) of the molecules (proteins, ions, nutrients, and ATP) less than 10 kDa across the membranes. (
  • The GPI anchor attaches (binds) to various proteins and then binds them to the outer surface of the cell membrane, ensuring that they are available when needed. (
  • GPI anchor-associated proteins that cannot attach to the cell membrane are released from the cell. (
  • It is unclear how PGAP2 gene mutations lead to the other features of Mabry syndrome, but these signs and symptoms are likely due to a lack of proper GPI anchoring of proteins to cell membranes. (
  • The shape and duration of each action potential are determined by the activity of ion channel protein complexes in the membranes of individual cells, and the genes encoding most of these proteins and their regulators have now been identified. (
  • The effect of gramicidin on the membrane potential of neurons in the C" by John DiCecco, Michael Segala et al. (
  • DiCecco, John, Michael Segala, Oleg Andreev, Yana Reshetnyak, and Ying Sun. "The effect of gramicidin on the membrane potential of neurons in the CNS of L. stagnalis. (
  • In neurons , the cell membrane is relatively impermeable to Cl‾: permeability to Cl‾ is about 1000 times less than that of K + , and therefore its contribution is often ignored. (
  • Whereas Na V 1.7 plays a pivotal role in the modulation of action potential threshold, Na V 1.8 channel is the predominant channel driving and shaping TTX-resistant action potentials (AP) in DRG neurons. (
  • 2. In neocortical slices taken from kindled rats, low-intensity electrical stimulation evoked generation of prolonged (hundreds of milliseconds) paroxysmal extracellular field potentials and intracellular depolarizing potentials, indicating synchronized activity of large populations of neurons. (
  • By contrast, in superficial (layer II/III) neurons the same stimulus evoked an EPSP that was followed by a prolonged response whose late component reversed at subthreshold membrane potentials (between -50 and -80 mV). (
  • Trade-off between dendritic democracy and independence in neurons with intrinsic subthreshold membrane potential oscillatio. (
  • For proper functioning of neurons and muscles during action potentials, voltage-gated sodium channels direct sodium ion diffusion for membrane depolarization. (
  • Effects of hypoxia on membrane potential and intracellular calcium in rat neonatal carotid body type I cells. (
  • The cell membrane provides a selectively permeant electrical barrier between the intracellular and extracellular compartments. (
  • the intracellular K + concentration is normally greater (150 mmol/L) than the extracellular K + concentration (5 mmol/L). The phospholipid bilayer of the cell membrane itself is impermeable to K + ions, as they are polar. (
  • Models fitted to intracellular spike and membrane potential recordings from frog (Rana temporaria). (
  • Fujita M, Kinoshita T. GPI-anchor remodeling: potential functions of GPI-anchors in intracellular trafficking and membrane dynamics. (
  • Action potentials in turn provide the primary signals to release Ca 2+ from intracellular stores (sarcoplasmic reticulum) and to thereby initiate contraction. (
  • During this period, the resting membrane potential of immature granule cells is relatively depolarized, but it becomes hyperpolarized in mature cells. (
  • In many neuronal cells, the resting membrane potential shifts from a relatively depolarized state to a more hyperpolarized one during development [ Nakanishi and Okazawa (2006) , and references therein]. (
  • A quiescent cell typically has a negative resting membrane potential (RMP). (
  • Although Na V 1.9 probably does not contribute to action potential amplitude, it most likely acts as a threshold channel, contributing to resting membrane potential and lowering the threshold for action potentials thereby increasing repetitive firing 4 . (
  • We addressed how persistent membrane depolarization influences the developmental and maturation processes of granule cells by depolarizing organotypic cultures with high KCl. (
  • 5. Under voltage recording conditions, anoxia induced a reversible membrane depolarization (or receptor potential) accompanied, in many cases, by trains of action potentials. (
  • PAF caused a rapid transient depolarization of the granulocyte membranes in the presence of extracellular Na+. (
  • Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization). (
  • Cardiac cells undergo depolarization and repolarization about 60 times per minute to form and propagate cardiac action potentials. (
  • In the presence of an inside-positive membrane potential, the negatively charged dye accumulates in the intravesicular aqueous space according to a Nernst equilibrium. (
  • The electrical potential across the membrane will be zero when there are exactly equal numbers of positively and negatively charged ions on either side of the cell membrane. (
  • 2017), a novel technique employing an Uzigirs dip cell arrangement used in conjunction with Laser Doppler Electrophoresis was used to characterize the surface of several negatively charged membranes. (
  • for the resting potential of isolated squid axons is less than that of other excitable cells (Hodgkin, 1951) and isprobably lowerthanthat intheliving animal. (
  • For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. (
  • Positively charged nanofiltration membranes: Review of current fabrication methods and introduction of a novel approach by: Christopher Wright, et al. (
  • Review of the dielectric properties of nanofiltration membranes and verification of the single oriented layer approximation by: Paul Williams, et al. (
  • Nanofiltration membranes and processes: A review of research trends over the past decade by: Darren Oatley-Radcliffe, et al. (
  • Subsequent observation with an atomic force fluorescence microscopy (Fig.1B) and revealed the presence of two planar DOPC bilayer membranes stacked on GO with the assistance of calcium ion (5 mM), and that the DOPC bilayers on GO were fluid and continuous with the surrounding DOPC bilayers on the bare SiO 2 surfaces (Fig. 1C). (
  • DESCRIPTION : This file contains a CellML description of Marhl et al's 1997 model of the interrelations between calcium oscillations and ER membrane potential oscillations. (
  • Smith, TC 1982, ' The use of flurescent dyes to measure membrane potentials: A response ', Journal of Cellular Physiology , vol. 112, no. 2, pp. 302-305. (
  • For example, the lipid bilayer is the fundamental structure of cell membranes, and the structure and dynamic of bilayer membranes govern the transport of materials and information in and out of cells. (
  • Artificial lipid bilayers on graphene and its derivatives could be a new cell membrane model system for the researche on fundamental processes in cell membrane reactions. (
  • A taste sensor with a multichannel electrode was developed by using lipid membranes as a transducer of taste substances. (
  • This investigation has demonstrated that alteration of the membrane potential and its downstream calcineurin signaling play a pivotal role in triggering the maturation program for the synaptic organization of postnatally developing granule cells. (
  • These problems include: (1) alteration of the membrane potential (E m ) and factors involved in establishing E m by the dyes themselves, (2) the effect of altered energy metabolism on the fluorescent response of the dyes and on E m , and (3) calibration of dye fluorescence. (
  • Experiments with large unilamellar dioleoylphosphatidylcholine vesicles were carried out in order to study the effect of membrane potential on the fluorescence of Oxonol VI. (
  • The fluorescence change can be calibrated as a function of transmembrane voltage by generating a potassium diffusion potential in the presence of valinomycin. (
  • the whole influence of voltage on the fluorescence results from voltage-dependent partitioning of the dye between water and membrane. (
  • Under this condition, fluorescence changes corresponding to (inside-positive) potentials of up to 150-200 mV are observed. (
  • Ross B, Loew LM, Baker B . Decision letter: Optical estimation of absolute membrane potential using fluorescence lifetime imaging Elife . (
  • The effects on transmembrane potential and hydrogen -peroxide release were determined by fluorescence techniques. (
  • Media containing unphysiological concentrations of potassium ion, drugs, affecting the Na+,K+ ATPase, or a channel-forming antibiotic, gramicidin, all affect lateral mobility of cell surface antigens in a manner consistent with a common effect on membrane potential. (
  • In the absence of Na+, PAF had no effect on membrane potential. (
  • Hence, it is necessary to record from neuronal dendrites, which generate dendritic action potentials (DAP) and profoundly influence neural computation and plasticity. (
  • Mapping of excitatory and inhibitory postsynaptic potentials of neuronal populations in hippocampal slices using the GEVI, ArcLight. (
  • Direct measurements of electroviscous phenomena in nafion membranes. (
  • Here, we map the electrical potentials along the membrane of differentiated N1E-115 neuroblastoma cells with a potential-sensitive dye. (
  • This investigation was conducted to examine the role of this alteration in membrane potential and its downstream signaling mechanism in development and maturation of granule cells. (
  • Two important questions, however, still remain to be clarified by studying primary cultures of dissociated granule cells: (1) Are the development and maturation of granule cells regulated by altered membrane potential and its downstream CaN signaling during the functional network formation of the postnatal cerebellum? (
  • These restrictions are altered by exposing either heterokaryons or their parent cells to conditions that change cell surface membrane potential. (
  • 1. We have studied the effects of hypoxia on membrane potential and [Ca2+]i in enzymically isolated type I cells of the neonatal rat carotid body (the principal respiratory O2 chemosensor). (
  • Indo-1 was loaded into cells using the esterified form indo-1 AM. Membrane potential was measured (and clamped) in single isolated type I cells using the perforated-patch (amphotericin B) whole-cell recording technique. (
  • When cells were voltage clamped close to their resting potential (-40 to -60 mV), the [Ca2+]i response to anoxia was greatly reduced and its onset was much slower. (
  • The ECM featured in human amniotic membrane (HAM) provides a suitable niche for the cells to adhere, grow, proliferate, migrate and differentiate, and could possibly contribute to the production of angiogenic micro-environment indirectly. (
  • imaging in mammalian prostate cancer cells that an early step in the signal cascade is direct action on the cell membrane potential. (
  • Wnts thus act as ligands for ion channel activation in mammalian cells and membrane potential is an early indicator of control of transcription. (
  • Hesperidin Preferentially Stimulates Transient Receptor Potential Vanilloid 1, Leading to NO Production and Mas Receptor Expression in Human Umbilical Vein Endothelial Cells. (
  • They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. (
  • To investigate the protective effects and potential mechanisms of estrogen modified human bone marrow mesenchymal stem cells (hBMSC) on high glucose (HG)-induced injury of vascular endothelial cells. (
  • Behavioral and neural responses of toads to salt solutions correlate with basolateral membrane potential of epidermal cells of the skin. (
  • Researchers at RPI have developed a prototype hydrocarbon-based membrane for use in AE fuel cells and electrolyzers. (
  • Interestingly, the new compound 3 exhibited more sensitivity on cancer cells than normal cells, highlighting its potential as a novel anti-cancer agent. (
  • Asbestos fiber dose, cellular microenvironment, and aberrations of the cell plasma membrane and/or cell cytoskeleton (i.e., microtubules and filaments) are discussed as potential factors in the changes noted in type II cells. (
  • The outer membrane surrounds the inner membrane creating an intermembrane space that contains molecules such as Cyt-C, SMAC/Diablo, and endonuclease G. It also acts as a buffer zone between the outer membrane and the inner membrane of mitochondria. (
  • The inner membrane of mitochondria allows the free transport of oxygen and carbon dioxide. (
  • We measured neocortical sub- and supra-threshold dendritic membrane potential (DMP) from putative distal-most dendrites using tetrodes in freely behaving rats over multiple days with a high degree of stability and sub-millisecond temporal resolution. (
  • One Sentence Summary Measurement of cortical dendritic membrane potential for several days in freely behaving rats reveals disproportionate dendritic spiking and analog and digital coding. (
  • Many types of single ply membranes deteriorate under water, Duro-Last PVC is warranted for ponding water and it does NOT cause deterioration. (
  • As TPO roofing gradually makes its way to the top of the single-ply membrane market, more commercial owners are getting curious and asking, "What is TPO? (
  • This type of single-ply membrane is produced using ethylene propylene and a mix of fillers, including fiberglass and talc. (
  • The use of fluorescent cyanine dyes to estimate membrane potential in cell suspensions has been considered. (
  • We herein review studies using the critical size supraalveolar periodontal defect model in which clinically meaningful periodontal regeneration was achieved following reconstructive surgery, including space provision by reinforced expanded polytetrafluoroethylene membranes or including surgical implantation of recombinant human bone morphogenetic protein-2. (
  • The movement of water through membranes is suggested to be controlled by aquaporins channel protein [ 22 , 23 ] though a report suggested otherwise [ 24 ]. (
  • As a result, the PGAP2 protein cannot efficiently modify the GPI anchor, likely impairing the anchor's ability to attach itself and its associated protein to the cell membrane. (
  • Nor do they provide much quantitative evidence about the influence of membrane potential onthe process responsible for inactivation. (
  • Due to its relatively depolarized voltage dependence of inactivation, Na V 1.8 can contribute to action potential generation even at depolarized membrane potentials which may occur during nerve injury or pain signalling 3 . (
  • Membrane fouling can easily be examined through monitoring permeate flux [of a compacted membrane], with both pressure and temperature held constant. (
  • The Membrane Potential system is designed to measure potential difference (∆U or emf) in millivolts between high and low salinity in shale sands at ambient temperature. (
  • Experimental investigation is done in the following cell with cation exchange membrane at a temperature of 25oC CATION Ag/AgCl/MCL (aqC1) /EXCHANGE/MCL (aqC1)/AgCl/Ag MEMBRANE This is done for the aqueous electrolyte solutions MCL, were M is the alkali metal cation Li+, Na+ and K+. (
  • When the chemical and electrical gradients are equal in magnitude, the ion is said to be in electrochemical equilibrium, and the membrane potential that is established at equilibrium is said to be the equilibrium potential ( V eq. ) for that ion under the existing concentration gradient. (
  • In filtration tests, while adding ~ 10 wt% graphene/Teflon to the glass fibre membrane decreased the flow rate by × 100, the selectivity improved by × 10 3 compared to the neat glass fibre membrane. (
  • Researchers at Rensselaer Polytechnic Institute (RPI) created a 3D computer simulation tool to assess the behavior/interaction of a hydrophobic membrane material with waste/feed water particles to assist membrane manufacturers/end-users in identifying a high performing membrane filtration/separation system. (
  • Thus they giveno information about the rate at whichrepolarization restores the abilityof the membrane torespond withits characteristic increase of sodium conductance. (
  • The influence of a small change in membrane potential on the abilityofthe membrane to undergo its increase in sodium permeability is illustrated by Fig. 1. (
  • The inner membrane is highly convoluted into structures called cristae, which increases the surface area of the membrane and are the seats of respiratory complexes. (
  • Effects of platelet activating factor on membrane potential and respiratory burst activity of human granulocytes. (
  • Oxonol VI was found to be suitable for detecting changes of membrane potential associated with the activity of the (Na+ + K+)-ATPase in reconstituted vesicles. (
  • A low-intensity stimulus to the white matter evoked an excitatory postsynaptic potential (EPSP) followed with variable latency by a paroxysmal depolarizing shift that reversed at suprathreshold membrane potentials and on which superimposed repetitive firing was always evident. (
  • The reversal potential of the response shifted toward suprathreshold membrane potentials and subsequently superimposed repetitive firing became evident. (
  • This study also indicated a potential beneficial role of repetitive elements in the human genome. (
  • First, we validated the chick embryo model using retinoic acid and then investigated the potential of CDK inhibitors on neuroblastoma cell differentiation, tumour progression and metastasis. (
  • Successful characterization of membranes is of paramount importance for the development and improvement of novel membranes and membrane processes. (
  • Activation of this recombinant channel, by membrane hyperpolarization, generated a slowly activating, noninactivating inward current. (
  • Although originally prescribed to treat cardiac failure, more recently they have been rediscovered for their potential anticancer activity. (
  • In this paper, positively charged modified PTFE membranes are fabricated and the novel zeta potential measurement technique is utilised to quantify the resultant membrane charge by use of a positively charged amidine tracer particle. (
  • Annealing the resultant composites leads to coalescence of the Teflon, resulting in very stable membranes with significantly enhanced mechanical properties. (
  • However, the equilibrium potential is typically reported in millivolts (mV). (
  • The characterisation of membrane charge is key to understanding charge interactions between the process stream and the membrane and is typically represen. (
  • TPO membranes typically come in white, black, and grey color variations. (
  • A possible reason could be that channels experience nonuniform electrical potentials along the plasmalemma. (
  • However, the cell membrane contains open K + leak channels 1 that permit K + to pass down its concentration gradient from the ICF to the ECF. (
  • Muscle contains open membrane Cl‾ channels. (
  • 1 ) ion concentration gradient across the membrane, and ( 2 ) selective ion channels in the membrane. (
  • The Nernst equation allows us to calculate the potential that will be established across the membrane based on the valence and concentration gradient of K + (provided that only K + channels are present). (
  • If only one ionic species is present in the system and channels for only the ionic species are present (and open), then V eq. will also be the membrane potential ( V m ). (
  • A negative membrane potential is produced when there is a greater number of positively charged ions on the outside of the cell membrane relative to the inside. (
  • However, membrane depolarisation results in a positively charged cell interior, producing a Cl‾ influx. (
  • Characterisation and application of a novel positively charged nanofiltration membrane for the treatment of textile industry wastewaters by: Paul Williams, et al. (
  • Operations in which aerosols may have been generated were carried out in biological safety cabinets to reduce the potential for inhalation exposure. (
  • Although some aerosols may have been released during the few reported rotor-seal failures involving the continuous-flow zonal centrifuge, the potential for contact exposure was greater. (
  • An important potential occupational route of exposure to opioids occurs by breathing air contaminated with airborne opioid particles. (
  • Standard Precautions include hand hygiene and the use of specific personal protective equipment (PPE) determined by the potential for exposure to blood, body fluids, and infectious material. (
  • After the build-up of the membrane potential, a quasi-stationary state is reached in which the pump current is compensated by a back-flow of charge through passive conductance pathways. (
  • The voltage dependence of the apparent partition coefficient can be quantitatively described by a three-capacitor model in which the dye is assumed to bind to adsorption planes located on the hydrocarbon side of the membrane / solution interface. (
  • The membrane potential of a cell is the electrical voltage of its interior relative to its exterior. (
  • Variable Consequences of Membrane Targeting Motifs for Genetically Encoded Voltage Indicators Biophysical Journal . (
  • The voltage differences across a membrane. (
  • For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. (
  • A non-zero membrane potential arises from inequalities in the distribution of charged ions across the cell membrane. (
  • The selective permeability of the cell membrane to the different ions. (
  • The ISE makes use of the unique properties of certain membrane materials to develop an electrical potential for the measurement of ions in solution. (
  • c) Clinical investigation is needed to evaluate propolis potential in patients or healthy individuals, to understand under which conditions propolis may promote health. (
  • Silver - silver Chloride electrodes are prepared and used for the measurements of the streaming potentials. (
  • A comparative analysis was made between the novel laser Doppler electrophoresis measurements and tangential streaming potential measurements for the positive membrane and the agreement was good. (
  • Serum electrolyte and red blood cell membrane potential of hypertensive patients in Owerri metropolis were investigated. (
  • The observed alterations in the parameters investigated in hypertensive subjects in the present study could be as a result of a host of derangements involving electrolyte metabolism, altered membrane transport and a possible increase in membrane fragility. (
  • This study has shown the serum electrolyte and red blood cell membrane potential of hypertensive patients in Owerri metropolis. (
  • This combination of selectively and flow rate was significantly better than any commercial membrane tested under similar circumstances. (
  • Since propolis-containing products have been marketed and humans have used propolis for different purposes, the goal of this review is to discuss the potential of propolis for the development of new drugs, by comparing data from the literature that suggest candidate areas for the establishment of drugs against tumors, infections, allergy, diabetes, ulcers and with immunomodulatory action. (
  • Phase-resetting curves and neuromodulation of action potential dynamics in the cortex. (
  • Neuroblastoma cell lines were engrafted on the chorioallantoic membrane (CAM) of chick embryos and allowed to form tumours over a 7 day period. (
  • Fouling potential is an important factor to consider when selecting a membrane for any given separation process. (
  • We learned that the movement of an ion across the membrane that is not balanced by the movement of a counter ion leads to charge separation across the membrane, and that this charge separation forms the basis for the establishment of a potential difference across the plasma membrane (i.e., membrane potential, V m ). (
  • Charge separation across the membrane leads to the establishment of an electrical gradient that grows in magnitude until it exactly balances the chemical gradient. (
  • The sensor can detect the taste in a similar manner to the human gustatory sensation by response patterns of electric potential to taste substances. (
  • The same taste as that elicited by some commercial aqueous drink was reproduced by making aqueous solution mixed from four kinds of basic taste substances, the concentrations of which were determined so that the electric-potential pattern of this mixed solution could agree well with the pattern by the drink. (