Physics: The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Membrane Potentials: 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).Nuclear Physics: The study of the characteristics, behavior, and internal structures of the atomic nucleus and its interactions with other nuclei. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Health Physics: The science concerned with problems of radiation protection relevant to reducing or preventing radiation exposure, and the effects of ionizing radiation on humans and their environment.Physical Phenomena: The entities of matter and energy, and the processes, principles, properties, and relationships describing their nature and interactions.Models, Biological: 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.Membrane Potential, Mitochondrial: 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.Physiology: The biological science concerned with the life-supporting properties, functions, and processes of living organisms or their parts.Petrolatum: A colloidal system of semisolid hydrocarbons obtained from PETROLEUM. It is used as an ointment base, topical protectant, and lubricant.Laboratories: Facilities equipped to carry out investigative procedures.Teaching: The educational process of instructing.Substantia Nigra: The black substance in the ventral midbrain or the nucleus of cells containing the black substance. These cells produce DOPAMINE, an important neurotransmitter in regulation of the sensorimotor system and mood. The dark colored MELANIN is a by-product of dopamine synthesis.Neurons: 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.Blood-Brain Barrier: Specialized non-fenestrated tightly-joined ENDOTHELIAL CELLS with TIGHT JUNCTIONS that form a transport barrier for certain substances between the cerebral capillaries and the BRAIN tissue.Microfluidic Analytical Techniques: Methods utilizing the principles of MICROFLUIDICS for sample handling, reagent mixing, and separation and detection of specific components in fluids.Diffusion: 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.Endothelial Cells: Highly specialized EPITHELIAL CELLS that line the HEART; BLOOD VESSELS; and lymph vessels, forming the ENDOTHELIUM. They are polygonal in shape and joined together by TIGHT JUNCTIONS. The tight junctions allow for variable permeability to specific macromolecules that are transported across the endothelial layer.Membranes, Artificial: 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.Trypanosoma cruzi: The agent of South American trypanosomiasis or CHAGAS DISEASE. Its vertebrate hosts are man and various domestic and wild animals. Insects of several species are vectors.Microfluidics: The study of fluid channels and chambers of tiny dimensions of tens to hundreds of micrometers and volumes of nanoliters or picoliters. This is of interest in biological MICROCIRCULATION and used in MICROCHEMISTRY and INVESTIGATIVE TECHNIQUES.Fusobacteria: A phylum of anaerobic, gram-negative bacteria with a chemoorganotrophic heterotrophic metabolism. They are resident flora of the OROPHARYNX.Adsorption: The adhesion of gases, liquids, or dissolved solids onto a surface. It includes adsorptive phenomena of bacteria and viruses onto surfaces as well. ABSORPTION into the substance may follow but not necessarily.Membranes: Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Intracellular Membranes: 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.Membrane Lipids: 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.src Homology Domains: Regions of AMINO ACID SEQUENCE similarity in the SRC-FAMILY TYROSINE KINASES that fold into specific functional tertiary structures. The SH1 domain is a CATALYTIC DOMAIN. SH2 and SH3 domains are protein interaction domains. SH2 usually binds PHOSPHOTYROSINE-containing proteins and SH3 interacts with CYTOSKELETAL PROTEINS.Dynamin I: A subtype of dynamin found primarily in the NEURONS of the brain.Endocytosis: Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.Protein Structure, Tertiary: 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.Dynamins: A family of high molecular weight GTP phosphohydrolases that play a direct role in vesicle transport. They associate with microtubule bundles (MICROTUBULES) and are believed to produce mechanical force via a process linked to GTP hydrolysis. This enzyme was formerly listed as EC 3.6.1.50.Erythrocyte Deformability: Ability of ERYTHROCYTES to change shape as they pass through narrow spaces, such as the microvasculature.Telefacsimile: A telecommunication system combining the transmission of a document scanned at a transmitter, its reconstruction at a receiving station, and its duplication there by a copier.Myotonia Congenita: Inherited myotonic disorders with early childhood onset MYOTONIA. Muscular hypertrophy is common and myotonia may impair ambulation and other movements. It is classified as Thomsen (autosomal dominant) or Becker (autosomal recessive) generalized myotonia mainly based on the inheritance pattern. Becker type is also clinically more severe. An autosomal dominant variant with milder symptoms and later onset is known as myotonia levior. Mutations in the voltage-dependent skeletal muscle chloride channel are associated with the disorders.Enteric Nervous System: Two ganglionated neural plexuses in the gut wall which form one of the three major divisions of the autonomic nervous system. The enteric nervous system innervates the gastrointestinal tract, the pancreas, and the gallbladder. It contains sensory neurons, interneurons, and motor neurons. Thus the circuitry can autonomously sense the tension and the chemical environment in the gut and regulate blood vessel tone, motility, secretions, and fluid transport. The system is itself governed by the central nervous system and receives both parasympathetic and sympathetic innervation. (From Kandel, Schwartz, and Jessel, Principles of Neural Science, 3d ed, p766)Molecular Probes: A group of atoms or molecules attached to other molecules or cellular structures and used in studying the properties of these molecules and structures. Radioactive DNA or RNA sequences are used in MOLECULAR GENETICS to detect the presence of a complementary sequence by NUCLEIC ACID HYBRIDIZATION.Time Factors: Elements of limited time intervals, contributing to particular results or situations.DenmarkAdenosine Triphosphate: 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.Kinetics: The rate dynamics in chemical or physical systems.Energy Metabolism: The chemical reactions involved in the production and utilization of various forms of energy in cells.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.Thermodynamics: A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)Biology: One of the BIOLOGICAL SCIENCE DISCIPLINES concerned with the origin, structure, development, growth, function, genetics, and reproduction of animals, plants, and microorganisms.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Periodicity: 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).Oscillometry: The measurement of frequency or oscillation changes.Biological Clocks: The physiological mechanisms that govern the rhythmic occurrence of certain biochemical, physiological, and behavioral phenomena.Liver, Artificial: Devices for simulating the activities of the liver. They often consist of a hybrid between both biological and artificial materials.Cryoprotective Agents: Substances that provide protection against the harmful effects of freezing temperatures.Cryopreservation: Preservation of cells, tissues, organs, or embryos by freezing. In histological preparations, cryopreservation or cryofixation is used to maintain the existing form, structure, and chemical composition of all the constituent elements of the specimens.Hepatocytes: The main structural component of the LIVER. They are specialized EPITHELIAL CELLS that are organized into interconnected plates called lobules.Dimethyl Sulfoxide: A highly polar organic liquid, that is used widely as a chemical solvent. Because of its ability to penetrate biological membranes, it is used as a vehicle for topical application of pharmaceuticals. It is also used to protect tissue during CRYOPRESERVATION. Dimethyl sulfoxide shows a range of pharmacological activity including analgesia and anti-inflammation.Freezing: Liquids transforming into solids by the removal of heat.Ethylene Glycol: A colorless, odorless, viscous dihydroxy alcohol. It has a sweet taste, but is poisonous if ingested. Ethylene glycol is the most important glycol commercially available and is manufactured on a large scale in the United States. It is used as an antifreeze and coolant, in hydraulic fluids, and in the manufacture of low-freezing dynamites and resins.

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,http://people.eku.edu/ritchisong/301notes2.htm,/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 ...
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 ...
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. ...
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 - Spike-Threshold Adaptation Predicted by Membrane Potential Dynamics In Vivo. AU - Fontaine, Bertrand. AU - Pena, Jose L.. AU - Brette, Romain. PY - 2014. Y1 - 2014. 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 potential at a short timescale. As a result, in these neurons, slow voltage ...
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 ...
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 body wall muscles in Drosophila larvae are suitable for voltage clamp analysis of changes in membrane excitability caused by mutations. Both inward and outward ionic currents are present in these muscle fibers. The inward current is mediated by voltage-dependent Ca2+ channels. In Ca2+-free saline, the inward current is eliminated. The remaining outward K+ currents consist of two distinct components, an early transient IA and a delayed steady IK, which are separable by differences in the rate and voltage dependence of activation and inactivation. The steady-state and kinetic properties of the activation and inactivation processes of these two currents are analyzed. The results provide a basis for quantitative analysis of altered membrane currents in behavioral mutants of Drosophila. Previous studies indicate that mutations in the Shaker (Sh) locus alter excitability in both nerve and muscle in Drosophila. Our results support the idea that the channels mediating IA are molecularly distinct ...
I agree that this is correct in the classical limit. However in http://disciplinas.stoa.usp.br/pluginfile.php/48089/course/section/16461/qsp_chapter10-plank.pdf 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 ...
View Notes - lecture_09_26 from NPB 100 at UC Davis. Resting Membrane Potential Lectures What you will learn in these lectures 1. You will learn that all cells, including neurons, have a resting
Passive properties refer to the capacitative and resistive aspects inherent in neuronal membranes, along with the resistivity inherent in the cytoplasm and the extracellular milieu. Together, these properties provide an electrical resemblance between neuronal processes (axons and dendrites) and conduction in electrical cables and hence are termed cable properties. Across this capacitive/resistive membrane an electric field and a voltage difference is maintained by the action of selective ion pumps. While the basic assumption of most electrophysiologists is that the membrane potential may be initially considered as having a resting value (the resting potential) that is uniformly distributed along neuronal compartments, this is an oversimplification, as the ionic conductances (and pumps) which are responsible for setting the resting potential need not have a fixed density throughout the neuronal membrane. Even so, isopotentiality is inherent in most initial cable property assumptions. The value of ...
Passive properties refer to the capacitative and resistive aspects inherent in neuronal membranes, along with the resistivity inherent in the cytoplasm and the extracellular milieu. Together, these properties provide an electrical resemblance between neuronal processes (axons and dendrites) and conduction in electrical cables and hence are termed cable properties. Across this capacitive/resistive membrane an electric field and a voltage difference is maintained by the action of selective ion pumps. While the basic assumption of most electrophysiologists is that the membrane potential may be initially considered as having a resting value (the resting potential) that is uniformly distributed along neuronal compartments, this is an oversimplification, as the ionic conductances (and pumps) which are responsible for setting the resting potential need not have a fixed density throughout the neuronal membrane. Even so, isopotentiality is inherent in most initial cable property assumptions. The value of ...
Inhibitory synapses release an inhibitory neurotransmitter that produces a transient hyperpolarisation called an Inhibitory Post-Synaptic Potential (IPSP). The mechanism is not dissimilar to that described above, except that the neurotransmitter acts on a different ligand-gated channel that opens the channel to potassium and/or chloride ions. The equilibrium potential of the IPSP is between -70 and -90 mV. As a result, when the membrane is already depolarised, the ion movements hyperpolarise the post-synaptic membrane. ...
Inside the cell membrane there is a well-defined environment, in which many complex biochemical processes take place. The interior of the cell differs in important respects from its outside. For example the contents of positive sodium and potassium ions and negatively charged chloride ions are quite different. This leads to a difference in electrical potential over the cell membrane, amounting to 0.03 to 0.1 volts. This is usually referred to as the membrane potential.. The cell uses the membrane potential in several ways. By rapidly opening channels for sodium ions the membrane potential is altered radically within a thousandth of a second. Cells in the nervous system communicate with each other by means of such electrical signals of around a tenth of a volt that rapidly travel along the nerve processes. When they reach the point of contact between two cells - the synapse - they induce the release of a transmitter substance. This substance affects receptors on the target cell, often by opening ...
TY - JOUR. T1 - Voltage-Dependent Inactivation of MscS Occurs Independently of the Positively Charged Residues in the Transmembrane Domain. AU - Nomura, Takeshi. AU - Sokabe, Masahiro. AU - Yoshimura, Kenjiro. PY - 2016. Y1 - 2016. N2 - MscS (mechanosensitive channel of small conductance) is ubiquitously found among bacteria and plays a major role in avoiding cell lysis upon rapid osmotic downshock. The gating of MscS is modulated by voltage, but little is known about how MscS senses membrane potential. Three arginine residues (Arg-46, Arg-54, and Arg-74) in the transmembrane (TM) domain are possible to respond to voltage judging from the MscS structure. To examine whether these residues are involved in the voltage dependence of MscS, we neutralized the charge of each residue by substituting with asparagine (R46N, R54N, and R74N). Mechanical threshold for the opening of the expressed wild-type MscS and asparagine mutants did not change with voltage in the range from -40 to +100 mV. By contrast, ...
Image Analyst MKII back-calculates mitochondrial and plasma membrane potentials in millivolts that drive changes in the fluorescence intensities.
Autor: Adams, P. R. et al.; Genre: Zeitschriftenartikel; Im Druck veröffentlicht: 1978; Titel: A comparison of current voltage relations of full and partial agonists
Smith, J.R., 1985: The electrical properties of plant cell membranes iii. the effects of insulated regions upon the cable properties and measured membrane conductance of charophytes
Video created by 杜克大学 for the course 医学神经科学. We now turn our attention from the tangible (human neuroanatomy) to the physiological as we explore the means by which neurons generate, propagate and communicate electrical signals. After exploring ...
Biological membrane potentials. The value of the signal is an electric potential ("voltage"). The domain is more difficult to ... Some cells or organelles have the same membrane potential throughout; neurons generally have different potentials at different ...
Unstable Membrane PotentialsEdit. Many cells have resting membrane potentials that are unstable. It is usually due to ion ... Slow wave potentialsEdit. Slow wave potential are unstable resting membrane potentials that continuously cycle through ... Pacemaker potentialsEdit. Pacemaker potentials are unstable cell membrane potentials that reach depolarization threshold with ... When the membrane potential reaches depolarization threshold an action potential (AP) is fired, excitation-contraction coupling ...
Resting potential Action potential Membrane potential http://cancerweb.ncl.ac.uk/cgi-bin/omd?action=Search+OMD&query= ... "CV Physiology: Membrane Potentials". Retrieved 8 November 2016. Hensley F, Martin D. A Practical Approach to Cardiac Anesthesia ... 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 ...
See the Membrane potential article. Free radical reactions are redox reactions that occur as a part of homeostasis and killing ... Standard electrode potentials (reduction potentials)[edit]. Each half-reaction has a standard electrode potential (E0. cell), ... The electrode potential of each half-reaction is also known as its reduction potential E0. red, or potential when the half- ... However, the potential of the reaction at the anode was sometimes expressed as an oxidation potential: E0. ox = -E0. red.. The ...
is the membrane potential, V. T. {\displaystyle V_{T}}. is the membrane potential threshold, τ. m. {\displaystyle \tau _{m}}. ... is the membrane time constant, E. m. {\displaystyle E_{m}}. is the resting potential, and Δ. T. {\displaystyle \Delta _{T}}. is ... Once the membrane potential crosses V. T. {\displaystyle V_{T}}. , it diverges to infinity in finite time.[10][11] ... term to the membrane potential, reflecting the diffusion of ions that occurs through the membrane when some equilibrium is not ...
Pidot, A. L.; Diamond, J. M. (1964). "Streaming Potentials in a Biological Membrane". Nature. 201: 701-702. doi:10.1038/ ... 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 ...
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 ...
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: ... Wolniak, S. M., P. K. Hepler, and W. T. Jackson (1980). "Detection of the membrane-calcium distribution during mitosis in ... Hepler, P. K. (1980). "Membranes in the mitotic apparatus of barley cells". Journal of Cell Biology. 86: 490-499. doi:10.1083/ ...
This causes a hyperpolarization of its membrane potential. This hyperpolarizing effect could lead to increased uptake of ...
Dielectric relaxation Dielectrophoresis Membrane potential. ... of cellular compartments and their surrounding membranes. ...
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 Pharmacalogy ... Measurements may indicate the site of action potential origin, and measurements of action potential velocity and direction may ...
They shift the threshold towards zero or hyperpolarize the membrane potential. Although each agent has its own properties and ... Heart potential[edit]. Azimilide dihydrochloride is a chlorophenylfuranyl compound, which slows repolarization of the heart and ... The effect comes from outside of the cell membrane and does not depend on G-proteins or kinase activity inside the cell. ... they prolong the duration of the action potential and the refractory period. Also they slow down the spontaneous discharge ...
Many cells have resting membrane potentials that are unstable. It is usually due to ion channels in the cell membrane that ... Slow wave potential are unstable resting membrane potentials that continuously cycle through depolarization- and repolarization ... Pacemaker potentials are unstable cell membrane potentials that reach depolarization threshold with every depolarization/ ... Membrane potential Action potential Excitation-contraction coupling Myogenic mechanism (Myogenic reflex). ...
Nuriya, Mutsuo; Jiang, Jiang; Nemet, Boaz; Eisenthal, Kenneth B.; Yuste, Rafael (2006). "Imaging membrane potential in ... It has also been used to prove that backpropagating action potentials invade dendritic spines without voltage attenuation, ...
Rhoades, Rodney A.; Bell, David R. (2012). "Plasma membrane. membrane transport, and resting membrane potential". Medical ... where the substances travel through the cell passing through both the apical membrane and basolateral membrane 2. Renal ... This transport can either be absorption, transport from lumen (apical membrane surface) to blood, or secretion, transport from ... the cell membrane is a hydrophobic environment and will not allow the passive diffusion of charged, hydrophilic, or zwitterion ...
"Mitochondrial membrane potential in living cells."Annu Rev Cell Biol. 4 (1988) 155-181 M. Huang, A. K. S. Camara, D. F. Stowe, ... 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 ...
The membrane also maintains the cell potential. The cell membrane thus works as a selective filter that allows only certain ... plasmatic membrane (Pfeffer, 1900),[13] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[14][15] Some ... The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ...
For example, if φ(x,y) denotes the displacement of a membrane above the domain D in the x,y plane, then its potential energy is ... A more general expression for the potential energy of a membrane is ... membranes do indeed assume configurations with minimal potential energy. Riemann named this idea the Dirichlet principle in ... The function that minimizes the potential energy with no restriction on its boundary values will be denoted by u. Provided that ...
Double sucrose gap, however, can measure the membrane potential and resistance. Another limitation is that membrane potentials ... The recording of membrane potentials in the superior cervical ganglion was made simple with the sucrose-gap method as it allows ... A pair of agar-bridged Ag-AgCl electrodes are placed in the test and KCl chambers to record the changes in membrane potential. ... When used with proper electronics, the double sucrose gap can be used to voltage clamp the membrane potential of the nerve or ...
Carandini, M; Ferster, D (2000). "Membrane potential and firing rate in cat primary visual cortex". Journal of Neuroscience. 20 ... membrane potential, and firing rate in visual cortex and discovered that prolonged visual stimulation causes a tonic ...
... makes this inactivation happen at less depolarized membrane potentials. This means that lacosamide only affects ... In a study conducted to assess the teratogenic potential of AEDs in the zebrafish embryo, the teratogenicity index of ... Inactivation only occurs in neurons firing action potentials; this means that drugs that modulate fast inactivation selectively ... This inactivation prevents the channel from opening, helping end the action potential. Many antiepileptic drugs, like ...
Other interesting uses of fluorescent proteins in the literature include using FPs as sensors of neuron membrane potential, ... "Genetically encoded fluorescent sensors of membrane potential". Brain Cell Biology. 36 (1-4): 53-67. doi:10.1007/s11068-008- ... Due to the potential for widespread usage and the evolving needs of researchers, many different mutants of GFP have been ... For example, mGFP often refers to a GFP with an N-terminal palmitoylation that causes the GFP to bind to cell membranes. ...
Effect of intralysosomal pH and membrane potential". The Journal of Biological Chemistry. 262 (3): 1244-53. PMID 2948955. ... The proton motive force (pmf) across the lysosomal membrane is generated by a V-type ATPase which hydrolyzes cytoplasmic ATP to ... Removal of the C-terminal GYDQL lysosomal sorting motif causes cystinosin to migrate to the plasma membrane with the ...
The effect of high membrane potential is thought to have a similar effect. Superoxide produced at the Qo site can be released ... In this cycle four protons get released into the positive "P" side (inter membrane space), but only two protons get taken up ... This could be explained by the fact that Complex III might produce superoxide as membrane permeable HOO• rather than as ... Complex III is present in the mitochondria of all animals and all aerobic eukaryotes and the inner membranes of most eubacteria ...
Apoptosis (quantification, measurement of DNA degradation, mitochondrial membrane potential, permeability changes, caspase ... they may also be attached to a chemical entity with affinity for the cell membrane or another cellular structure. Each ... This patented technology allows a highly accurate cell analysis and provides additional information like membrane capacitance ...
Though successful in predicting the timing and qualitative features of the action potential, it nevertheless failed to predict ... from membrane currents, proteins, and chemical coupling to network oscillations, columnar and topographic architecture, and ... Huxley developed the voltage clamp and created the first biophysical model of the action potential. Hubel & Wiesel discovered ... "A quantitative description of membrane current and its application to conduction and excitation in nerve". J. Physiol. 117 (4 ...
Membrane Potential. Molecular Mass. Nanoparticle Surface Characteristic. Nanoparticle Topology. Nanopore. Nanoscale Phenomena. ... Zeta Potential. pH. Copyright © Cancer Terms 2014 All rights reserved. , Terms of Use , Low Carb Foods. No reproduction or ... Oxidation-Reduction Potential. Physical Composition. Physical Contact. Physical State. Physical Symmetry. Polyvalence. Pressure ...
... "membrane potential" refers to the transmembrane potential. dipole potential surface potential Membrane potential (also ... The term "membrane potential" may refer to one of three kinds of membrane potential: transmembrane potential-covered in this ... 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 ...
Neurons produce action potentials when their membrane potential increases past a critical threshold. If the voltage is below ... but the membrane potential still fluctuates due to postsynaptic potentials and intrinsic electrical properties of neurons. In ... beyond synaptic and action potentials, rhythmic subthreshold membrane potential oscillations (a particular type of neural ... Subthreshold membrane potential oscillations are rhythmic fluctuations of the voltage difference between the interior and ...
... potential is depolarized to a critical potential (Ecrit), a self-generating action potential follows, leading to muscle ... Phase 0, the upstroke, is associated with a sudden increase in membrane permeability to Na+. Phases 1, 2, and 3 result from ... changes in membrane permeability and conductance to Na+, K+, and Ca2+. ... Other articles where Critical membrane potential is discussed: muscle: The frequency of contraction: … ...
Membrane potential definition at Dictionary.com, a free online dictionary with pronunciation, synonyms and translation. Look it ... membrane potential. n.. *The potential inside a cell membrane measured relative to the fluid just outside; it is negative under ...
Membrane potential and gentamicin uptake in Staphylococcus aureus. S M Mates, E S Eisenberg, L J Mandel, L Patel, H R Kaback, M ... Membrane potential and gentamicin uptake in Staphylococcus aureus. S M Mates, E S Eisenberg, L J Mandel, L Patel, H R Kaback, M ... Membrane potential and gentamicin uptake in Staphylococcus aureus. S M Mates, E S Eisenberg, L J Mandel, L Patel, H R Kaback, ... At pH 5.0, the electrical potential (delta psi, interior negative) across the plasma membrane of Staphylococcus aureus exhibits ...
Membrane potential (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 ... Changes to membrane potential during developmentEdit. A neurons resting membrane potential actually changes during the ... The term "membrane potential" may refer to one of three kinds of membrane potential:[1] ...
Rather, it is the *tendency* of movements to occur (which depends on changing permeabilities) that governs membrane potential. ... no net ionic flux occurs and the membrane potential is stable. The NE is dependent on two things, the permeability of the ... the ionic flux required to swing a membrane from neutral to the NE potential is so slight that the original internal and ... is responsible for causing the resting membrane potential. Just a small leak (relatively) is sufficient to establish the ...
Membrane potential is the voltage that exists across the membrane of a cell. Its particularly important in nerve cells, since ... A membrane potential is the voltage which exists across the membrane of a cell. It is also known as a transmembrane potential, ... where the cell membrane goes through a process called depolarization. After the action potential, the membrane potential ... Membrane potentials arise because cell membranes do not allow sodium and potassium ions to pass freely in and out of cells and ...
For the membrane potential channel (1), multiply the values by 0.1 to remove the instrumentation gain. This gives the membrane ... Squid Giant Axon Membrane Potential. This data set, its source, and the methods used to generate it, are described in ... The membrane potential and stimulus current are given for a total of 170 trials across 8 different axons. ... potential in volts.. *For the stimulus current channel (2), apply the physical unit conversion, 1V = 5uA/cm2 to get the ...
Imaging Membrane Potential with Two Types of Genetically Encoded Fluorescent Voltage Sensors, Whole-cell Patch-clamp ... Membrane Potentials, Synaptic Responses, Neuronal Circuitry, Neuromodulation and Muscle Histology Using the Crayfish: Student ... Surface Potential Measurement of Bacteria Using Kelvin Probe Force Microscopy, The Preparation of Oblique Spinal Cord Slices ... Modeling Biological Membranes with Circuit Boards and Measuring Electrical Signals in Axons: Student Laboratory Exercises, ...
Membrane-SPINE: A Biochemical Tool to Identify Protein-protein Interactions of Membrane Proteins In Vivo, Functional Magnetic ... Monitoring Changes in Membrane Polarity, Membrane Integrity, and Intracellular Ion Concentrations in Streptococcus pneumoniae ... Membrane Transport Processes Analyzed by a Highly Parallel Nanopore Chip System at Single Protein Resolution, Three- ... Targeted Plasma Membrane Delivery of a Hydrophobic Cargo Encapsulated in a Liquid Crystal Nanoparticle Carrier, Preparation ...
Early events are represented by ion flux unbalances that eventually lead to plasma transmembrane potential (Vm) variations. ... I. Membrane potentials, intracellular calcium variations, oral secretions, and regurgitate components. Plant Physiol 134:1752- ... Zebelo S.A., Maffei M.E. (2012) Signal Transduction in Plant-Insect Interactions: From Membrane Potential Variations to ... Signal Transduction in Plant-Insect Interactions: From Membrane Potential Variations to Metabolomics. ...
Because persister cells have a lower membrane potential than normal cells, we hypothesize that persister cells have reduced ... This is a ~4 times increase compared to treatment without membrane depotentiation which only led to 22.0 ± 3.3% killing. ...
... Chi-Won Choi,1,2 ... "Potential Usefulness of Streptococcus pneumoniae Extracellular Membrane Vesicles as Antibacterial Vaccines," Journal of ...
It was strongly speculated that the membrane potential origin could lie primarily in the ion adsorption on the membrane (or ... The adsorption theory attributes the membrane potential generation to the ion adsorption onto the membrane (or separator) ... variation of membrane permeability to ion in accordance with ion species results in the variation of the membrane potential. ... It might be necessary to reconsider the origin of membrane potential which has been so far believed explicable by the GHK ...
Video created by Peking University for the course Advanced Neurobiology I. Lets switch to the electrical properties of the neuron. 2000+ courses from schools like Stanford and Yale - no application required. Build career skills in data ...
Video created by Peking University for the course Advanced Neurobiology I. Lets switch to the electrical properties of the neuron. Learn online and earn valuable credentials from top universities like Yale, Michigan, Stanford, and leading ...
... dc.contributor.author. Oh, Seungeun. ... "Label-Free Imaging of Membrane Potential Using Membrane Electromotility." Biophysical Journal 103, no. 1 (July 2012): 11-18. © ... membrane potential. We find that the observed optical signals are due to membrane electromotility, which causes the cells to ... Membrane electromotility-induced cell deformation may be useful as a reporter of electrical activity.. en_US. ...
The formation of vesicles at the plasma membrane is mediated by the G protein dynamin that catalyzes the final fission step, ... Taken together, our results suggest a versatile role for pacsin-1 in sculpting cellular membranes that is likely dependent both ... Theoretical free energy calculations suggest bimodality of the protein-membrane system as a possible source for the different ... In addition, liposomes prepared with different methods yield distinct membrane deformation morphologies of BAR domain proteins ...
... and hyperpolarized membrane potentials (blue), together with the expected response at the hyperpolarized membrane potential ( ... Membrane Potential Changes in Dendritic Spines during Action Potentials and Synaptic Input. Lucy M. Palmer and Greg J. Stuart ... Membrane potential values were corrected for a 12 mV junction potential. Pooled data are presented as mean ± SEM. Statistical ... Comparison of the spine response at resting membrane potentials (21.1 ± 3.8 mV; n = 13) with that at hyperpolarized membrane ...
Dendritic attenuation of synaptic potentials and currents: the role of passive membrane properties.. Spruston N1, Jaffe DB, ... Voltage-gated channels might influence the measurement of passive membrane properties and, reciprocally, passive membrane ... The pattern of activation of these synaptic inputs determines if the neuron will fire an action potential at any given point in ... The authors review recent data from patch-clamp recordings that provide new estimates of the passive membrane properties of ...
... an impaired ETC is not able to generate a mitochondrial membrane potential. ρ° cells are able to sustain mitochondrial membrane ... G) Mitochondrial membrane potential assessed by TMRE (50nM) staining and corrected by CCCP (50 μM) of DN-POLG-GFP/BFP and DN- ... TCA Cycle and Mitochondrial Membrane Potential Are Necessary for Diverse Biological Functions.. Martínez-Reyes I1, Diebold LP1 ... Mitochondrial membrane potential dependent ROS is essential for hypoxic stabilization of HIF-1α protein and cell proliferation ...
Wafer-scale mitochondrial membrane potential assays Tae-Sun Lim,a Antonio Davila Jr,bc Katayoun Zand,a Douglas C. Wallacec and ... Wafer-scale mitochondrial membrane potential assays T. Lim, A. Davila Jr, K. Zand, D. C. Wallace and P. J. Burke, Lab Chip, ... Membrane potential changes of isolated mitochondria from various well-established cell lines such as human HeLa cell line ( ... structural durability and reproducibility while increasing the sensitivity to changes in mitochondrial membrane potential by an ...
... Lars Thomsen lthomsen at aix1.danadata.dk Sat Aug 5 ... I would like to know if anyone has experience with fluorecent probes for measuring membrane potential. I know that Molecular ...
  • I was not even satisfied with what my standard med school physiology texts taught me about membrane equilibria, so I had done some research then. (physicsforums.com)
  • Together, these findings underscore the concept that the cell envelope and membrane vesicles contain crucial, yet under-explored determinants of GC physiology, which may represent promising targets for designing new therapeutic interventions. (mcponline.org)
  • The fundamental cellular parameters of cell volume ( V c ) and resting membrane potential ( E m ) profoundly influence cellular, tissue, organ and whole-body physiology. (bl.uk)
  • In this talk, I will discuss the performance of the membranes towards removal of natural organic matter such as tannic acid, and perfluoro-octanoic acid (PFOA) - a typical compound associated with degradation of fluorinated organics. (aiche.org)
  • The need was to find a way of controlling the architecture of membrane micro-structures in a predictable way so that the performance of the membranes can be predicted and controlled from the outset of designing the membranes," said Dr. Darrell Patterson, the director for the Centre for Advanced Separations Engineering at the University of Bath, and an author of the study. (watec-israel.com)
  • Production of large unilamellar vesicles by a rapid extrusion procedure: characterization of size distribution, trapped volume and ability to maintain a membrane potential. (semanticscholar.org)
  • Development activities at Applied Biomimetics Inc. focuses on incorporation of aquaporins in colloidal polymer vesicles and development of a coating platform using colloidal particles as membrane building blocks. (techconnectworld.com)
  • Despite the implied role of the GC cell envelope and membrane vesicles in colonization and infection of human tissues and cell lines, comprehensive studies have not been undertaken to elucidate their constituents. (mcponline.org)
  • Focusing on one of them, a homolog of an outer membrane protein LptD, we demonstrated that its depletion caused loss of GC viability. (mcponline.org)
  • Thus, when the electrode is immersed in a solution of pH 7, the sum of these fixed voltages approximately balances the voltage developed on the outer surface of the glass membrane and a separate reference element. (google.com)
  • The FLIPR® Membrane Potential Assay Kit combines the benefits of highly informative data that you can get with patch clamping, with the benefits of high-throughput screening that can be obtained with the FLIPR system. (selectscience.net)
  • And because the dye in the Membrane Potential Assay Kit is much less sensitive to temperature changes than DiBAC, plates can be set up ahead of time and stacked for batch runs, making the assay highly amenable to automation. (selectscience.net)
  • This second generation integrated lab-on-a-chip system developed here shows enhanced structural durability and reproducibility while increasing the sensitivity to changes in mitochondrial membrane potential by an order of magnitude as compared to first generation technologies. (rsc.org)
  • Mollica MP, Iossa S, Liverini G, Soboll S. Steady state changes in mitochondrial electrical potential and proton gradient in perfused liver from rats fed a high fat diet. (harvard.edu)
  • Instead, special passages known as ion channels permit potassium ions to move out through the cell membrane, reducing the positive charge inside the cell. (wisegeek.com)
  • The Ca 2+ channels are most probably activated by the depolarizing receptor potentials resulted from the PFOS-induced activation of chemoreceptors. (go.jp)
  • The membrane then becomes capable of selectively removing and recovering the molecules and particles that cause fouling and utilizing materials that don't age, to increase the lifespan of a membrane. (watec-israel.com)
  • Fast-response probes are commonly used to image electrical activity from intact heart tissues or measure membrane potential changes in response to pharmacological stimuli. (thermofisher.com)
  • Applying that to a clinical scenario you can see why hyperkalemia and hypokalemia would have a bigger consequence in tissues like muscle,heart and neurons, which required a certain resting potential in order to function properly. (valuemd.com)
  • In apoptotic cells, the mitochondrial membrane potential collapses, which results in failure to retain JC-10 dye and the dye returns to its monomeric green form (EX/Em= 490/525 nm) in the cytosol. (gbiosciences.com)
  • Importantly, mutating the extended N-terminal region to reduce its amphipathicity resulted in the accumulation of GFP in the cytosol of the chlamydiae and not in the membrane. (asm.org)