Changes in intracellular potentials and ionic currents of the mollusk and activity of Cl--channels under exposure to some inhibitory amino acids and new litium-containing compounds of them

2015 ◽  
Vol 13 (3) ◽  
pp. 39-47 ◽  
Author(s):  
Petr Dmitrievich Shabanov ◽  
Anatoliy Ivanovich Vislobokov ◽  
Georgiy Nolianovich Shilov ◽  
P M Bulay ◽  
A P Lugovskii
Keyword(s):  
Amino Acids ◽  
Chloride Channels ◽  
Impulse Activity ◽  
Ionic Current ◽  
Ionic Currents ◽  
Dependent Manner ◽  
Cl Channels ◽  
Ganglion Neurons ◽  
Inhibitory Amino Acids ◽  
Dose Dependent

The Changes of membrane rest potential (RP), action potential (AP), impulse activity (IA) as well as sodium, calcium and potassium ionic currents in neurons of isolated central nervous system of the Planorbarius corneus mollusk (pedal ganglia) under the extracellular action of inhibitory amino acids GABA, glycine and β-alanine and their litium-containing derivatives (LCD) in 0.1, 1 and 5 mM concentrations have been studied using a microelectrode technique. They induced the same dose-dependent and irreversible depolarization of neurons on 2-10 mV accompanied by increase of AP frequency, prolongation of their duration and decrease of summmerized ionic currents (dV/dt). According to degree of depolarization, the drugs were placed in the following range in decreasing activity: compound 3 > compound 2 > compound 1. In identified pedal ganglion neurons (PPed1), compound 3 in contrast to other compounds induced hyperpolarization by 2-10 mV and blocked impulse activity. The amplitude of sodium and calcium channels was decreased by 7-15 %, in the same degree after application of all compounds exposed in concentration of 5 mM. Efflux potassium ionic currents were increased in dose-dependent manner and irreversibly about by 3-7 % assessed on amplitude indexes without changes in kinetic parameters after application of LCD. Therefore, the decrease of ionic current amplitudes was due to both depolarization of neurons and direct action of LCD on ionic channels. Thus, LCD possess membranotropic activity and can modulate functional state of neurons. In the study of chloride channels in cells culture of rat glioma C6 in vitro by patch-clamp method, GABA, glycine, β-alanine and their LCD 10 µM/l activated chloride channels, shifting equiliblium membrane potential of glioma cells from -90… -70 mV to -55... -60 mV. All compounds (transmitters and LCD) were placed in the following range: glycine > GABA > β-alanine and compound 1 > compound 3 > compound 2 according to descending activity. Therefore, the most active compounds activating Cl--channels were glycine and compound 1 (LCD). Glycine was shown to be coagonist GABA receptors and its litium salt possessed significant membranotropic activity.

Bone as an ion exchange system: evidence for a link between mechanotransduction and metabolic needs

2002 ◽  
Vol 282 (4) ◽  
pp. E851-E864 ◽  
Author(s):  
A. Rubinacci ◽  
M. Covini ◽  
C. Bisogni ◽  
I. Villa ◽  
M. Galli ◽  
...  
Keyword(s):  
Current Density ◽  
Ex Vivo ◽  
Ionic Current ◽  
Extracellular Fluid ◽  
Ionic Currents ◽  
Dependent Manner ◽  
Metabolic Functions ◽  
Metatarsal Bones ◽  
Dose Dependent

To detect whether the mutual interaction occurring between the osteocytes-bone lining cells system (OBLCS) and the bone extracellular fluid (BECF) is affected by load through a modification of the BECF-extracellular fluid (ECF; systemic extracellular fluid) gradient, mice metatarsal bones immersed in ECF were subjected ex vivo to a 2-min cyclic axial load of different amplitudes and frequencies. The electric (ionic) currents at the bone surface were measured by a vibrating probe after having exposed BECF to ECF through a transcortical hole. The application of different loads and different frequencies increased the ionic current in a dose-dependent manner. The postload current density subsequently decayed following an exponential pattern. Postload increment's amplitude and decay were dependent on bone viability. Dummy and static loads did not induce current density modifications. Because BECF is perturbed by loading, it is conceivable that OBLCS tends to restore BECF preload conditions by controlling ion fluxes at the bone-plasma interface to fulfill metabolic needs. Because the electric current reflects the integrated activity of OBLCS, its evaluation in transgenic mice engineered to possess genetic lesions in channels or matrix constituents could be helpful in the characterization of the mechanical and metabolic functions of bone.

scholarly journals Simonkolleite Coating on Poly(Amino Acids) to Improve Osteogenesis and Suppress Osteoclast Formation in Vitro

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1505 ◽  
Author(s):  
Shuyang Li ◽  
Xingtao Chen ◽  
Xiaomei Wang ◽  
Yi Xiong ◽  
Yonggang Yan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Osteoclast Formation ◽  
Mouse Bone Marrow ◽  
Graft Material ◽  
Dependent Manner ◽  
E Coli ◽  
Ft Ir ◽  
Dose Dependent ◽  
Relative Cell Viability

Zinc can enhance osteoblastic bone formation and stimulate osteogenic differentiation, suppress the differentiation of osteoclast precursor cells into osteoclasts, and inhibit pathogenic bacterial growth in a dose-dependent manner. In this study, simonkolleite, as a novel zinc resource, was coated on poly (amino acids) (PAA) via suspending PAA powder in different concentrations of zinc chloride (ZnCl2) solution, and the simonkolleite-coated PAA (Zn–PAA) was characterized by SEM, XRD, FT-IR and XPS. Zinc ions were continuously released from the coating, and the release behavior was dependent on both the concentration of the ZnCl2 immersing solution and the type of soak solutions (SBF, PBS and DMEM). The Zn–PAA was cultured with mouse bone marrow stem cells (BMSCs) through TranswellTM plates, and the results indicated that the relative cell viability, alkaline phosphatase (ALP) activity and mineralization of BMSCs were significantly higher with Zn–PAA as compared to PAA. Moreover, the Zn–PAA was cultured with RAW264.7 cells, and the results suggested an inhibiting effect of Zn–PAA on the cell differentiation into osteoclasts. In addition, Zn–PAA exhibited an antibacterial activity against both S. aureus and E. coli. These findings suggest that simonkolleite coating with certain contents could promote osteogenesis, suppress osteoclast formation and inhibit bacteria, indicating a novel way of enhancing the functionality of synthetic bone graft material and identifying the underline principles for designing zinc-containing bone grafts.

Inhibition of macromolecular synthesis by caffeine in Clostridium perfringens

1987 ◽  
Vol 33 (7) ◽  
pp. 589-592 ◽  
Author(s):  
Ronald G. Labbe ◽  
Linda L. Nolan
Keyword(s):  
Amino Acids ◽  
Clostridium Perfringens ◽  
Dependent Manner ◽  
Macromolecular Synthesis ◽  
Dose Dependent

Caffeine (2 mg/mL) inhibited the incorporation of [14C]adenine into actively growing cells of Clostridium perfringens NCTC 8679 in a dose-dependent manner. Also reduced by caffeine was incorporation of [14C]thymidine and 14C-labeled amino acids. No effect on guanine, uracil, adenosine, guanosine, or uridine was detected. Actual incorporation of [14C]caffeine or [14C]thymine in control cultures did not occur.

scholarly journals Modulation of electrical activity and ionic currents of isolated neurons by orexin A

2013 ◽  
Vol 11 (4) ◽  
pp. 54-60
Author(s):  
Petr Dmitriyevich Shabanov ◽  
Anatoliy Ivanovich Vislobokov
Keyword(s):  
Membrane Potential ◽  
Lymnaea Stagnalis ◽  
Ionic Currents ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Isolated Neurons ◽  
Orexin A ◽  
High Concentrations ◽  
Kinetics Of ◽  
Dose Dependent

The changes in intracellular potential of resting (PR) and potential of action (PA) of the identified neurons of pedal and visceral ganglia of the CNS mollusk Planorbarius corneus registered by means of intracellular electrodes, and ionic currents of isolated neurons under fixed potential after administration of orexin A in concentrations 1, 10, 100 and 1000 µg/ml were studied by the method of fixation of membrane potential in isolated neurons of the Lymnaea stagnalis mollusk. Dibazol in concentrations of 1 and 10 µM effected slightly on the ionic currents. High concentrations of dibazol (100 and 1000 µM) inhibited all currents in dose dependent manner with maximal effect on potassium currents amplitude. ЕС50 were 7.4 мМ for INa, 4.0 мМ for ICa, 83.9 µM for IKs,1 (one group of neurons) and 2.9 мМ for IKs,2 (the another group of neurons). The voltage-amper membrane characteristics shift was not registered, but the kinetics of currents development was changed. Dibazol was more effective in inhibition of ionic currents compared to its structural analogs.

scholarly journals Single-Molecule Dynamics and Discrimination between Hydrophilic and Hydrophobic Amino Acids in Peptides, through Controllable, Stepwise Translocation across Nanopores

2018 ◽  
Author(s):  
Alina Asandei ◽  
Isabela S. Dragomir ◽  
Giovanni Di Muccio ◽  
Mauro Chinappi ◽  
Yoonkyung Park ◽  
...  
Keyword(s):  
Amino Acids ◽  
Single Molecule ◽  
Ionic Current ◽  
Ionic Currents ◽  
Alpha Hemolysin ◽  
Time Discrimination ◽  
Voltage Dependent ◽  
Hydrophobic Amino Acids ◽  
Molecular Brake ◽  
Oppositely Charged

In this work we demonstrate the proof-of-concept of real-time discrimination between patches of serine or isoleucine monomers in the primary structure of custom-engineered, macro-dipole-like peptides, at uni-molecular level. We employed single-molecule recordings to examine the ionic current through the α-hemolysin (α-HL) nanopore, when hydrophilic serine or hydrophobic isoleucine residues, flanked by segments of oppositely charged arginine and glutamic amino acids functioning as a voltage-dependent ‘molecular brake’ on the peptide, were driven at controllable rates across the nanopore. The observed differences in the ionic currents blockades through the nanopore, visible at time resolutions corresponding to peptide threading through the α-HL’s constriction region, was explained by a simple model of the volumes of electrolyte excluded by either amino acid species, as groups of three serine or isoleucine monomers transiently occupy the α-HL. To provide insights into the conditions ensuring optimal throughput of peptide readout through the nanopore, we probed the sidedness-dependence of peptide association to and dissociation from the electrically and geometrically asymmetric α-HL.

TMEM16 Ca2+ Activated Cl– Channels and CLC Chloride Channels and Transporters

2018 ◽  
Author(s):  
Anna Boccaccio ◽  
Michael Pusch
Keyword(s):  
Synaptic Vesicles ◽  
Dorsal Root ◽  
Chloride Channels ◽  
Dorsal Root Ganglion Neurons ◽  
Equilibrium Potential ◽  
Recessive Mutations ◽  
Auxiliary Subunit ◽  
Cl Channels ◽  
Ganglion Neurons ◽  
Cellular Compartments

After the identification of TMEM16 proteins as the molecular counterparts of Ca2+-activated Cl– channels, their roles in shaping excitability in several parts of the central and peripheral nervous system are emerging. Their contribution might be excitatory, as in dorsal root ganglion neurons and olfactory sensory neurons, or at the contrary, contributing to hyperpolarization, as in thalamocortical neurons, being strictly related to the equilibrium potential for chloride that can differ among cells or cellular compartments. The ClC-2 channel, together with its auxiliary subunit GlialCAM, is most important in glia, and mutations in the CLCN2 and GLIALCAM genes lead to leukodystrophy. The endo/lysosomal chloride/proton antiporters ClC-3, ClC-4, ClC-6, and ClC-7/Ostm1 are involved in the homeostasis of endosomes and lysosomes, and ClC-3/ClC-4 may be involved in neurotransmitter loading of synaptic vesicles. Mutations in CLCN4 cause intellectual disability, and recessive mutations in CLCN7 or OSTM1 are associated with neurodegeneration.

Adenosine triphosphate regulates the activity of guinea pig Cav1.2 channel by direct binding to the channel in a dose-dependent manner

2014 ◽  
Vol 306 (9) ◽  
pp. C856-C863 ◽  
Author(s):  
Rui Feng ◽  
Jianjun Xu ◽  
Etsuko Minobe ◽  
Asako Kameyama ◽  
Lei Yang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Guinea Pig ◽  
Terminal Region ◽  
Atp Binding ◽  
Dependent Manner ◽  
Channel Activity ◽  
Fusion Peptides ◽  
Patch Clamp Technique ◽  
Binding Effect ◽  
Dose Dependent

The present study is to investigate the mechanism by which ATP regulates Cav1.2 channel activity. Ventricular tissue was obtained from adult guinea pig hearts using collagenase. Ca2+ channel activity was monitored using the patch-clamp technique. Proteins were purified using wheat germ agglutinin-Sepharose, and the concentration was determined using the Coomassie brilliant blue technique. ATP binding to the Cav1.2 channel was examined using the photoaffinity method. EDA-ATP-biotin maintains Ca2+ channel activity in inside-out membrane patches. ATP directly bound to the Cav1.2 channel in a dose-dependent manner, and at least two molecules of ATP bound to one molecule of the Cav1.2 channel. Low levels of calmodulin (CaM) increased ATP binding to the Cav1.2 channel, but higher levels of CaM decreased ATP binding to the Cav1.2 channel. In addition, Ca2+ was another regulator for ATP binding to the Cav1.2 channel. Furthermore, ATP bound to GST-fusion peptides of NH2-terminal region (amino acids 6–140) and proximal COOH-terminal region (amino acids 1,509–1,789) of the main subunit (α1C) of the Cav1.2 channel. Our data suggest that ATP might regulate Cav1.2 channel activity by directly binding to the Cav1.2 channel in a dose-dependent manner. In addition, the ATP-binding effect to the Cav1.2 channel was both CaM- and Ca2+ dependent.

scholarly journals Serum Metabolites Responding in a Dose-Dependent Manner to the Intake of a High-Fat Meal in Normal Weight Healthy Men Are Associated with Obesity

Metabolites ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 392
Author(s):  
Ueli Bütikofer ◽  
David Burnand ◽  
Reto Portmann ◽  
Carola Blaser ◽  
Flurina Schwander ◽  
...  
Keyword(s):  
Amino Acids ◽  
Branched Chain Amino Acids ◽  
Normal Weight ◽  
Dependent Manner ◽  
Metabolic Dysfunction ◽  
High Fat ◽  
Randomized Controlled ◽  
Two Factors ◽  
Branched Chain ◽  
Dose Dependent

Although the composition of the human blood metabolome is influenced both by the health status of the organism and its dietary behavior, the interaction between these two factors has been poorly characterized. This study makes use of a previously published randomized controlled crossover acute intervention to investigate whether the blood metabolome of 15 healthy normal weight (NW) and 17 obese (OB) men having ingested three doses (500, 1000, 1500 kcal) of a high-fat (HF) meal can be used to identify metabolites differentiating these two groups. Among the 1024 features showing a postprandial response, measured between 0 h and 6 h, in the NW group, 135 were dose-dependent. Among these 135 features, 52 had fasting values that were significantly different between NW and OB men, and, strikingly, they were all significantly higher in OB men. A subset of the 52 features was identified as amino acids (e.g., branched-chain amino acids) and amino acid derivatives. As the fasting concentration of most of these metabolites has already been associated with metabolic dysfunction, we propose that challenging normal weight healthy subjects with increasing caloric doses of test meals might allow for the identification of new fasting markers associated with obesity.

Production of superoxide and TNF-α from alveolar macrophages is blunted by glycine

1999 ◽  
Vol 277 (5) ◽  
pp. L952-L959 ◽  
Author(s):  
Michael D. Wheeler ◽  
Ronald G. Thurman
Keyword(s):  
Intracellular Calcium ◽  
Kupffer Cells ◽  
Alveolar Macrophages ◽  
Chloride Channel ◽  
Chloride Channels ◽  
Dependent Manner ◽  
Tnf Α ◽  
The Central Nervous System ◽  
Factor Α ◽  
Dose Dependent

Glycine blunts lipopolysaccharide (LPS)-induced increases in intracellular calcium concentration ([Ca2+]i) and tumor necrosis factor-α (TNF-α) production by Kupffer cells through a glycine-gated chloride channel. Alveolar macrophages, which have a similar origin as Kupffer cells, play a significant role in the pathogenesis of several lung diseases including asthma, endotoxemia, and acute inflammation due to inhaled bacterial particles and dusts. Therefore, studies were designed here to test the hypothesis that alveolar macrophages could be inactivated by glycine via a glycine-gated chloride channel. The ability of glycine to prevent endotoxin [lipopolysaccharide (LPS)]-induced increases in [Ca2+]iand subsequent production of superoxide and TNF-α in alveolar macrophages was examined. LPS caused a transient increase in intracellular calcium to nearly 200 nM, with EC50values slightly greater than 25 ng/ml. Glycine, in a dose-dependent manner, blunted the increase in [Ca2+]i, with an IC50less than 100 μM. Like the glycine-gated chloride channel in the central nervous system, the effects of glycine on [Ca2+]iwere both strychnine sensitive and chloride dependent. Glycine also caused a dose-dependent influx of radiolabeled chloride with EC50values near 10 μM, a phenomenon which was also inhibited by strychnine (1 μM). LPS-induced superoxide production was also blunted in a dose-dependent manner by glycine and was reduced ∼50% with 10 μM glycine. Moreover, TNF-α production was also inhibited by glycine and also required nearly 10 μM glycine for half-inhibition. These data provide strong pharmacological evidence that alveolar macrophages contain glycine-gated chloride channels and that their activation is protective against the LPS-induced increase in [Ca2+]iand subsequent production of toxic radicals and cytokines.

scholarly journals Rapid and Direct Action of Lipopolysaccharide (LPS) on Skeletal Muscle of Larval Drosophila

Biology ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1235
Author(s):  
Rachel Potter ◽  
Alexis Meade ◽  
Samuel Potter ◽  
Robin L. Cooper
Keyword(s):  
Skeletal Muscle ◽  
Direct Action ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Cellular Energy ◽  
Energy Demands ◽  
Cl Channels ◽  
Calcium Activated Potassium Channels ◽  
Oxide Synthase ◽  
Dose Dependent

The endotoxin lipopolysaccharide (LPS) from Gram-negative bacteria exerts a direct and rapid effect on tissues. While most attention is given to the downstream actions of the immune system in response to LPS, this study focuses on the direct actions of LPS on skeletal muscle in Drosophila melanogaster. It was noted in earlier studies that the membrane potential rapidly hyperpolarizes in a dose-dependent manner with exposure to LPS from Pseudomonas aeruginosa and Serratia marcescens. The response is transitory while exposed to LPS, and the effect does not appear to be due to calcium-activated potassium channels, activated nitric oxide synthase (NOS), or the opening of Cl− channels. The purpose of this study was to further investigate the mechanism of the hyperpolarization of the larval Drosophila muscle due to exposure of LPS using several different experimental paradigms. It appears this response is unlikely related to activation of the Na-K pump or Ca2+ influx. The unknown activation of a K+ efflux could be responsible. This will be an important factor to consider in treatments of bacterial septicemia and cellular energy demands.

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