Abstract:
:Large-conductance chloride channels (maxi-Cl channels) were studied in cultured myoblasts (L6 rat muscle cell line); in excised (inside-out) and in cell attached membrane patches using a conventional patch clamp method. The incidence of maxi-Cl channels was substantially higher in proliferating myoballs, then in quiescent (bottom-attached) myoblasts (90% and 50% percent of examined cells, respectively). The maxi-Cl channels in myoballs were present both in cell attached and excised patches. The channel conductance at symmetric [Cl] = 150 mmol/l was 359 +/- 42 pS (n = 74) in quiescent cells and 439 +/- 10 pS (n = 6) in proliferating myoballs respectively. The conductance of the channel in quiescent cells increased with chloride concentration in symmetric NaCl rich solutions according to Michaelis-Menten curve with the saturation limiting conductance of about 640 pS (gmax) and Km = 112 mmol/l. The shift of the reversal potential upon increasing the pipette concentration of NaCl from 150 to 250 mmol/l was consistent with PNa/PCl = 0.1. Neither the conductance nor the activation of the channel were dependent on the presence of calcium ions. The bell-shaped steady state channel conductance-voltage relationship is asymmetric and can be fitted by two Boltzmann equations with different Vh and k constants; -25.6 mV and -6.8 mV, respectively, for the negative side and +49.6 mV and +13.7 mV for the positive side in quiescent cells. The corresponding values in proliferating myoballs were as follows: -15.5 mV and -2.4 mV, respectively, for the negative side and +31.4 mV and +6.8 mV for the positive side. From the maximum slopes of the Popen versus V curves an estimate was made of the charges for the gates that close at negative (3.5) or positive (1.7) potentials, respectively, in quiescent cells. The corresponding values in myoballs were 10.6 and 3.7, respectively. The probability of one gate to be open was dependent on the state of activation of the opposite gate as determined by prepulses of the opposite polarity. The channel showed multiple (up to six) conductance levels that may develop in a step-like manner. The onset of the full-grown maxi-Cl channel is fairly abrupt; it might, however, be preceded by a small conductance unit activity. It is supposed that the differences between the quiescent myoblasts and proliferating myoballs might reflect increased expression of maxi-Cl channels in myoballs to perform as yet unknown role in the cell cycle and/or proliferation of the myoblasts.
journal_name
Gen Physiol Biophysjournal_title
General physiology and biophysicsauthors
Hurnák O,Zachar Jsubject
Has Abstractpub_date
1994-06-01 00:00:00pages
171-92issue
3eissn
0231-5882issn
1338-4325journal_volume
13pub_type
杂志文章abstract::The dynamics of a bioreactor with a variable volume and an active solute flux based on the thermodynamics of irreversible processes and stability analysis was studied. The active solute flux may control both the bioreactor volume and the hydrostatic pressure as well as the concentration of the solute inside the cell i...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1988-02-01 00:00:00
abstract::Sodium nitroprusside (SNP) is a nitric oxide (•NO) donor in vitro and in vivo. In this paper the time variation of the intracellular water proton nuclear magnetic resonance (NMR) effective relaxation time T'(2a) in SNP-treated human erythrocyte suspensions, containing 10 mM membrane impermeable paramagnetic MnCl2, has...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2010_04_373
更新日期:2010-12-01 00:00:00
abstract::Changes in the Young elasticity modulus in perpendicular direction to the membrane surface E perpendicular, in the coefficient of dynamic viscosity eta, in the electric capacitance C, in the surface charge U1, in the conductivity g and in the coefficient of non-linearity beta of current-voltage characteristic caused b...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1987-04-01 00:00:00
abstract::This study specified the role of several key calcium-operating ion channels in contraction/relaxation of human detrusor muscle as possible target for overactive bladder (OAB) treatment. Detrusor samples, obtained from 18 males (average age 61.5 ± 5.9 years), were investigated by organ tissue bath method with following...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2017064
更新日期:2018-07-01 00:00:00
abstract::The aim of the present work was to test the sensitivity of young male Wistar rats, Dobrá Voda (Dv:WI) to the diabetogenic effect of streptozotocin (STZ) with regard to their health condition and mortality rates. Eight-week-old rats, weighing from 200 to 230 g, were randomised into five groups of eight animals. Strepto...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1999-10-01 00:00:00
abstract::Aquaporin attracted attention not only of physiologists and biophysicists, but also of chemical engineers. Here we critically analyze a paper describing aquaporin-based artificial membranes, suggested for forward osmosis-based water purification (Wang et al. 2012, Small 8, pp. 1185-1190). Related papers published late...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2013058
更新日期:2013-12-01 00:00:00
abstract::Mitochondrial nucleoids (hereafter nucleoids) contain genetic information, mitochondrial DNA, prerequisite for mitochondrial functioning, particularly information required for mitochondrial electron transport. To understand nucleoid functioning, it is imperative to know its ultrastructure and dynamics in the context o...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2016008
更新日期:2016-07-01 00:00:00
abstract::A method has been proposed for the kinetic analysis of the relaxation phase of mechanical response of smooth muscle. The method implies linearization of the entire mechano-kinetic relaxation curve using the coordinates ln[(fm-f)/f]; ln t (where fm and f are the maximal and the actual values of force within the relaxat...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1991-12-01 00:00:00
abstract::The effect of melatonin on reperfusion arrhythmias and postischemic contractile dysfunction was studied in the isolated rat heart. 25 min global ischemia was induced and followed by 30 min of reperfusion. Melatonin (10 micromol/l) was present in the perfusion solution during the whole experiment. Experiment revealed p...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:2005-09-01 00:00:00
abstract::Charcot-Marie-Tooth disease (CMT) and related peripheral neuropathies are the most commonly inherited neurological disorders in humans, characterized by clinical and genetic heterogeneity. The most prevalent clinical entities belonging to this group of disorders are CMT type 1A (CMT1A) and hereditary neuropathy with l...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2011_04_379
更新日期:2011-12-01 00:00:00
abstract::Phosphorylation of P-glycoprotein (PGP) by some protein kinases may play an important role in the regulation of its drug transport activity, and may also be important for the development of multidrug resistance (MDR) phenotype. In the present study we investigated the expression of three groups of mitogen-activated pr...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1999-03-01 00:00:00
abstract::Electron spin resonance spectroscopy (ESR) was used to study the effects of amphiphilic amines of the carbamate, amide, and ester type and amine oxide on the photosynthetic system of spinach chloroplasts. The ESR signal II connected to the photosynthetic center PS II donor side was observed to diminish in the presence...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1990-12-01 00:00:00
abstract::Expression of the haptoglobin (Hp) gene is liver specific and acute phase (AP) responsive. It was previously shown that transcriptional induction process of the rat Hp gene during turpentine induced AP response has been mediated by the liver nucleoprotein p29 which was shown to be homologous to the HMG-1 chromatin-ass...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:2001-12-01 00:00:00
abstract::Cytochrome P-450 and NADPH: cytochrome P-450 reductase were solubilized by detergents from microsomal fraction of tulip bulbs Tulipa fosteriana L. and purified to electrophoretic homogeneity. The purification was achieved by anion-exchange column chromatography, hydroxyapatite-column chromatography and affinity chroma...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1994-04-01 00:00:00
abstract::PC12 cells differentiated under the influence of the neuronal growth factor (NGF) serve as a model of both sympathetic neurons and chromaffin cells. NGF-induced differentiation critically depends on elevated intracellular calcium concentration. Main pathway for Ca²⁺ entry in excitable cells is represented by voltage-d...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2014045
更新日期:2015-04-01 00:00:00
abstract::The purpose of this study was to assess the possible protective effects of Artemisia campestris against fenthion-induced nephrotoxicity in adult rats and their progeny. Fenthion was administered orally at a dose of 551 ppm, which represented ¼ of LD50, for 21 consecutive days to pregnant and lactating rats. Oxidative ...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2013047
更新日期:2013-12-01 00:00:00
abstract::The crystallization behaviour of the highly thermostable glucose isomerase from the Streptomyces sp. strain isolated from Tunisian soil was investigated using ammonium sulfate as a precipitating agent. We established phase diagrams at different temperatures and protein concentrations. It was found that the solubility ...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2013077
更新日期:2014-01-01 00:00:00
abstract::Lignin, the structural polymer of the plant cell walls, is produced by free radical polymerization of phenolic alcohols, catalyzed by different peroxidases. The mechanism and the structural organization of lignin in the cell have not been completely understood. In this study we applied fractal analysis to images of li...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:2000-06-01 00:00:00
abstract::Results of studies on the modulation of skeletal muscle contraction by phosphorylation of myosin regulatory light chains and by exchange of magnesium for calcium in myosin heads were reviewed. The polarized fluorescence method was used in these studies, and conformational changes of contractile proteins accompanying m...
journal_title:General physiology and biophysics
pub_type: 杂志文章,评审
doi:
更新日期:1991-06-01 00:00:00
abstract::The effect of binding of an antitumour drug cis-diamminedichloroplatinum(II) (cis-[Pt(NH3)2Cl2]) to DNA on cutting effectiveness of BamHI, EcoRI, and SalI restriction endonucleases was quantitatively determined. The platinum complex inhibits the cleavage of plasmid pHC624 DNA linearized by BglI restrictase. From the p...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1992-12-01 00:00:00
abstract::Salts of divalent cadmium are well-known human mutagens and carcinogens. In the present work, the ability of vitamin C to modulate genotoxic effects of cadmium chloride on human lymphocytes was assessed using single cell gel electrophoresis (comet assay). Vitamin C at 20 and 100 micromol/l and cadmium at 5, 30 and 150...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:2000-12-01 00:00:00
abstract::Although high-intensity electric fields (HEF) application is currently the only effective therapy available to terminate ventricular fibrillation, it may cause injury to cardiac cells. In this study we determined the relation between HEF pulse length and cardiomyocyte lethal injury. We obtained lethality curves by sur...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2015047
更新日期:2016-04-01 00:00:00
abstract::The role of viscosity in coupling between chemical reaction (complex formation) and diffusion in membranes has been investigated. The Fick law was replaced by the momentum balance equation with the viscous term. The irreversible thermodynamics admits coupling of the chemical reaction rate with the gradient of velocity...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1984-04-01 00:00:00
abstract::Depression is a brain disorder characterized by severe emotional, cognitive, neuroendocrine and somatic dysfunction. Although the latest generation of antidepressant drugs has improved clinical efficacy and safety, the onset of their clinical effect is significantly delayed after treatment commencement, and a large nu...
journal_title:General physiology and biophysics
pub_type: 杂志文章,评审
doi:10.4149/gpb_2015013
更新日期:2015-10-01 00:00:00
abstract::The effects of both chronic hypoxia and acute intermittent hypoxia (AIH) on cardiovascular system are unclear. We designed this study to develop a rabbit model of hypertension by exposure to chronic hypobaric hypoxia (CHH) and to investigate the effects of AIH on hypertensive rabbits. Present study was performed in 13...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2013070
更新日期:2014-01-01 00:00:00
abstract::Diabetes mellitus leads to bone disorders such as osteopenia and osteoporosis that can increase fracture risk. On the other hand, sodium tungstate is an inorganic compound which exerts anti-diabetic activity in experimental studies due to its suggested insulin-mimetic or antioxidant activity. Therefore this study was ...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2014020
更新日期:2014-01-01 00:00:00
abstract::The mechanisms underlying the renoprotective effect for remote limb ischemic preconditioning (rIPC) against renal ischemia/reperfusion injury need further elucidation. In our work, one hundred and twenty male Sprague Dawley rats were randomized into 3 groups; sham, I/R group (left renal 45 min ischemia) and rIPC (as I...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2015035
更新日期:2016-01-01 00:00:00
abstract::7,8-Dihydroxyflavone (7,8-DHF) is a natural flavonoid compound that act as Trk-B agonist. 7,8-DHF is also a potent antioxidant. When applied systematically, 7,8-DHF can pass through blood-brain barrier and exhibit potential therapeutic effects in several animal models of neurodegenerative disorders. This study investi...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2020022
更新日期:2020-09-01 00:00:00
abstract::The effects of alamethicin on the membrane barrier function of rabbit erythrocytes, human platelets and sarcoplasmic reticulum vesicles, as well as on that of brain microsomes and liver mitochondria of the rat were compared. An upset of the barrier function was observed for plasma membranes of brain microsomes as well...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:
更新日期:1992-02-01 00:00:00
abstract::We studied the involvement of O2, pH and low molecular thiols in H2S-induced decomposition of S-nitrosoglutathione (GSNO). The GSNO decomposition - •NO release was evaluated by UV-VIS spectroscopy and Griess assay. The H2S donor Na2S was used. O2 slightly increased, but was not necessary for the H2S-induced GSNO decom...
journal_title:General physiology and biophysics
pub_type: 杂志文章
doi:10.4149/gpb_2013026
更新日期:2013-09-01 00:00:00