Excitation-Metabolism Coupling in Skeletal Muscle: Caa-Dependent OO Consumption and Spreading of Mitochondria Membrane Potential

2018 ◽  
Author(s):  
A. DDaz-Vegas ◽  
A. Cordova ◽  
D. Valladares ◽  
P. Llanos ◽  
C. Hidalgo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Mitochondria Membrane Potential

scholarly journals Dose Response of Endotoxin on Hepatocyte and Muscle Mitochondrial Respiration In Vitro

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Victor Jeger ◽  
Sebastian Brandt ◽  
Francesca Porta ◽  
Stephan M. Jakob ◽  
Jukka Takala ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Mitochondrial Respiration ◽  
Hepg2 Cells ◽  
Human Hepatocytes ◽  
Atp Content ◽  
Muscle Mitochondria ◽  
Complex Ii ◽  
Skeletal Muscle Mitochondria ◽  
Reduced Time

Introduction.Results on mitochondrial dysfunction in sepsis are controversial. We aimed to assess effects of LPS at wide dose and time ranges on hepatocytes and isolated skeletal muscle mitochondria.Methods.Human hepatocellular carcinoma cells (HepG2) were exposed to placebo or LPS (0.1, 1, and 10 μg/mL) for 4, 8, 16, and 24 hours and primary human hepatocytes to 1 μg/mL LPS or placebo (4, 8, and 16 hours). Mitochondria from porcine skeletal muscle samples were exposed to increasing doses of LPS (0.1–100 μg/mg) for 2 and 4 hours. Respiration rates of intact and permeabilized cells and isolated mitochondria were measured by high-resolution respirometry.Results.In HepG2 cells, LPS reduced mitochondrial membrane potential and cellular ATP content but did not modify basal respiration. Stimulated complex II respiration was reduced time-dependently using 1 μg/mL LPS. In primary human hepatocytes, stimulated mitochondrial complex II respiration was reduced time-dependently using 1 μg/mL LPS. In isolated porcine skeletal muscle mitochondria, stimulated respiration decreased at high doses (50 and 100 μg/mL LPS).Conclusion.LPS reduced cellular ATP content of HepG2 cells, most likely as a result of the induced decrease in membrane potential. LPS decreased cellular and isolated mitochondrial respiration in a time-dependent, dose-dependent and complex-dependent manner.

scholarly journals Relationships between resting conductances, excitability, and t-system ionic homeostasis in skeletal muscle

2011 ◽  
Vol 138 (1) ◽  
pp. 95-116 ◽  
Author(s):  
James A. Fraser ◽  
Christopher L.-H. Huang ◽  
Thomas H. Pedersen
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Conduction Velocity ◽  
Electrical Response ◽  
Quantitative Description ◽  
Ion Concentration ◽  
Ionic Homeostasis ◽  
Voltage Gated ◽  
Concentration Changes ◽  
T System

Activation of skeletal muscle fibers requires rapid sarcolemmal action potential (AP) conduction to ensure uniform excitation along the fiber length, as well as successful tubular excitation to initiate excitation–contraction coupling. In our companion paper in this issue, Pedersen et al. (2011. J. Gen. Physiol. doi:10.1085/jgp.201010510) quantify, for subthreshold stimuli, the influence upon both surface conduction velocity and tubular (t)-system excitation of the large changes in resting membrane conductance (GM) that occur during repetitive AP firing. The present work extends the analysis by developing a multi-compartment modification of the charge–difference model of Fraser and Huang to provide a quantitative description of the conduction velocity of actively propagated APs; the influence of voltage-gated ion channels within the t-system; the influence of t-system APs on ionic homeostasis within the t-system; the influence of t-system ion concentration changes on membrane potentials; and the influence of Phase I and Phase II GM changes on these relationships. Passive conduction properties of the novel model agreed with established linear circuit analysis and previous experimental results, while key simulations of AP firing were tested against focused experimental microelectrode measurements of membrane potential. This study thereby first quantified the effects of the t-system luminal resistance and voltage-gated Na+ channel density on surface AP propagation and the resultant electrical response of the t-system. Second, it demonstrated the influence of GM changes during repetitive AP firing upon surface and t-system excitability. Third, it showed that significant K+ accumulation occurs within the t-system during repetitive AP firing and produces a baseline depolarization of the surface membrane potential. Finally, it indicated that GM changes during repetitive AP firing significantly influence both t-system K+ accumulation and its influence on the resting membrane potential. Thus, the present study emerges with a quantitative description of the changes in membrane potential, excitability, and t-system ionic homeostasis that occur during repetitive AP firing in skeletal muscle.

scholarly journals Single-cell-based evaluation of sperm progressive motility via fluorescent assessment of mitochondria membrane potential

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Natalina Moscatelli ◽  
Barbara Spagnolo ◽  
Marco Pisanello ◽  
Enrico Domenico Lemma ◽  
Massimo De Vittorio ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Single Cell ◽  
Mitochondria Membrane Potential ◽  
Progressive Motility

scholarly journals Koumine Promotes ROS Production to Suppress Hepatocellular Carcinoma Cell Proliferation Via NF-κB and ERK/p38 MAPK Signaling

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 559 ◽  
Author(s):  
Yuan ◽  
Liang ◽  
Yi ◽  
Chen ◽  
Li ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
Membrane Potential ◽  
P38 Mapk ◽  
Developed Countries ◽  
Mapk Signaling ◽  
Dependent Manner ◽  
Ros Production ◽  
Mitochondria Membrane Potential ◽  
Hcc Cells

In the past decades, hepatocellular carcinoma (HCC) has been receiving increased attention due to rising morbidity and mortality in both developing and developed countries. Koumine, one of the significant alkaloidal constituents of Gelsemium elegans Benth., has been regarded as a promising anti-inflammation, anxiolytic, and analgesic agent, as well as an anti-tumor agent. In the present study, we attempted to provide a novel mechanism by which koumine suppresses HCC cell proliferation. We demonstrated that koumine might suppress the proliferation of HCC cells and promote apoptosis in HCC cells dose-dependently. Under koumine treatment, the mitochondria membrane potential was significantly decreased while reactive oxygen species (ROS) production was increased in HCC cells; in the meantime, the phosphorylation of ERK, p38, p65, and IκBα could all be inhibited by koumine treatment dose-dependently. More importantly, the effects of koumine upon mitochondria membrane potential, ROS production, and the phosphorylation of ERK, p38, p65, and IκBα could be significantly reversed by ROS inhibitor, indicating that koumine affects HCC cell fate and ERK/p38 MAPK and NF-κB signaling activity through producing excess ROS. In conclusion, koumine could inhibit the proliferation of HCC cells and promote apoptosis in HCC cells; NF-κB and ERK/p38 MAPK pathways could contribute to koumine functions in a ROS-dependent manner.

scholarly journals Strophanthidin-sensitive sodium fluxes in metabolically poisoned frog skeletal muscle.

1976 ◽  
Vol 68 (4) ◽  
pp. 405-420 ◽  
Author(s):  
B G Kennedy ◽  
P De Weer
Keyword(s):  
Skeletal Muscle ◽  
Membrane Potential ◽  
Human Erythrocyte ◽  
Sodium Pump ◽  
Giant Axon ◽  
Squid Giant Axon ◽  
Frog Skeletal Muscle ◽  
Na Efflux ◽  
Unidirectional Fluxes ◽  
External K

Strophanthidin-sensitive and insensitive unidirectional fluxes of Na were measured in fog sartorius muscles whose internal Na levels were elevated by overnight storage in the cold. ATP levels were lowered, and ADP levels raised, by metabolic poisoning with either 2,4-dinitrofluorobenzene or iodoacetamide. Strophanthidin-sensitive Na efflux and influx both increased after poisoning, while strophanthidin-insensitives fluxes did not. The increase in efflux did not require the presence of external K but was greatly attenuated when Li replaced Na as the major external cation. Membrane potential was not markedly altered by 2,4-dinitrofluorobenzene. These observations indicate that the sodium pump of frog skeletal muscle resembles that of squid giant axon and human erythrocyte in its ability to catalyze Na-Na exchange to an extent determined by intracellular ATP/ADP levels.

Construction of the FRET Pairs for the Visualization of Mitochondria Membrane Potential in Dual Emission Colors

2019 ◽  
Vol 91 (5) ◽  
pp. 3704-3709 ◽  
Author(s):  
Ruiqing Feng ◽  
Lifang Guo ◽  
Jinglong Fang ◽  
Yue Jia ◽  
Xueying Wang ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Dual Emission ◽  
Mitochondria Membrane Potential
Sign in / Sign up

Export Citation Format

Share Document