scholarly journals Voltage-Dependent Sarcolemmal Ion Channel Abnormalities in the Dystrophin-Deficient Heart

2018 ◽  
Vol 19 (11) ◽  
pp. 3296 ◽  
Author(s):  
Xaver Koenig ◽  
Janine Ebner ◽  
Karlheinz Hilber
Keyword(s):  
Ion Channel ◽  
Current Knowledge ◽  
Intracellular Protein ◽  
Gene Encoding ◽  
Skeletal Muscle Weakness ◽  
Ion Channel Properties ◽  
Voltage Dependent ◽  
Dystrophin Deficiency ◽  
Underlying Mechanisms ◽  
Channel Properties

Mutations in the gene encoding for the intracellular protein dystrophin cause severe forms of muscular dystrophy. These so-called dystrophinopathies are characterized by skeletal muscle weakness and degeneration. Dystrophin deficiency also gives rise to considerable complications in the heart, including cardiomyopathy development and arrhythmias. The current understanding of the pathomechanisms in the dystrophic heart is limited, but there is growing evidence that dysfunctional voltage-dependent ion channels in dystrophin-deficient cardiomyocytes play a significant role. Herein, we summarize the current knowledge about abnormalities in voltage-dependent sarcolemmal ion channel properties in the dystrophic heart, and discuss the potentially underlying mechanisms, as well as their pathophysiological relevance.

Effects of intracellular pH and calcium activity on ion currents in internally perfused neurons of the snail Lymnaea stagnalis

1987 ◽  
Vol 65 (5) ◽  
pp. 994-1000 ◽  
Author(s):  
William J. Moody ◽  
Lou Byerly
Keyword(s):  
Ion Channel ◽  
Lymnaea Stagnalis ◽  
Ionic Composition ◽  
Channel Current ◽  
Ion Channel Properties ◽  
Internal Ph ◽  
Voltage Dependent ◽  
Ion Sensitive Microelectrodes ◽  
Degree Of Control ◽  
Channel Properties

The suction pipet method of intracellular dialysis and voltage clamp of cells has proven extremely useful in analysing the electrical properties of cells too small for the application of conventional microelectrode techniques and in larger cells for studying the effects of alterations in the internal ionic composition. Using neurons of the snail Lymnaea stagnalis, we have analysed several problems involved in the latter application of this technique and present several solutions to them. One major problem centers around the degree of control over the ionic composition of the cytoplasm achieved by altering the pipet solution. Using ion-sensitive microelectrodes during internal dialysis, we found that the efficiency of exchange between pipet and cytoplasm was much poorer for highly buffered ions such as H+ and Ca2+, than for K+, for example. Special precautions are described that can help this situation. The second problem involves the study of the effects of low internal pH on ion-channel properties. We summarize evidence for a specific voltage-dependent hydrogen ion channel, current through which becomes prominent at low internal pH. We analyse how the presence of this heretofore unrecognized current can seriously confuse the results of experiments designed to study the effects of low internal pH on other voltage-dependent currents.

Ion Channel Remodelling in Atrial Fibrillation

2011 ◽  
Vol 7 (2) ◽  
pp. 97 ◽  
Author(s):  
Niels Voigt ◽  
Dobromir Dobrev ◽  
◽  
Keyword(s):  
Atrial Fibrillation ◽  
Ion Channel ◽  
Antiarrhythmic Drugs ◽  
Current Knowledge ◽  
Bleeding Complications ◽  
Large Size ◽  
Cardiovascular Morbidity And Mortality ◽  
Number Of Patients ◽  
Life Threatening ◽  
Underlying Mechanisms

Atrial fibrillation (AF) is the most common arrhythmia and is associated with substantial cardiovascular morbidity and mortality, with stroke being the most critical complication. Present drugs used for the therapy of AF (antiarrhythmics and anticoagulants) have major limitations, including incomplete efficacy, risks of life-threatening proarrhythmic events and bleeding complications. Non-pharmacological ablation procedures are efficient and apparently safe, but the very large size of the patient population allows ablation treatment of only a small number of patients. These limitations largely result from limited knowledge about the underlying mechanisms of AF and there is a hope that a better understanding of the molecular basis of AF may lead to the discovery of safer and more effective therapeutic targets. This article reviews the current knowledge about AF-related ion-channel remodelling and discusses how these alterations might affect the efficacy of antiarrhythmic drugs.

scholarly journals The ion channel properties of a rat recombinant neuronal nicotinic receptor are dependent on the host cell type

1997 ◽  
Vol 505 (2) ◽  
pp. 299-306 ◽  
Author(s):  
Trevor M. Lewis ◽  
Patricia C. Harkness ◽  
Lucia G. Sivilotti ◽  
David Colquhoun ◽  
Neil S. Millar
Keyword(s):  
Ion Channel ◽  
Host Cell ◽  
Nicotinic Receptor ◽  
Cell Type ◽  
Neuronal Nicotinic Receptor ◽  
Ion Channel Properties ◽  
Channel Properties

Ion-channel properties of mastoparan, a 14-residue peptide from wasp venom, and of MP3, a 12-residue analogue

1990 ◽  
Vol 239 (1296) ◽  
pp. 383-400 ◽  
Keyword(s):  
Ion Channels ◽  
Lipid Bilayers ◽  
Type I ◽  
Type Ii ◽  
Channel Formation ◽  
Channel Inactivation ◽  
Ion Channel Properties ◽  
Discrete Channel ◽  
Voltage Dependent ◽  
Channel Properties

Mastoparan, a 14-residue peptide, has been investigated with respect to its ability to form ion channels in planar lipid bilayers. In the presence of 0.3 - 3.0 μ M mastoparan, two types of activity are seen. Type I activity is characterized by discrete channel openings, exhibiting multiple con­ductance levels in the range 15-700 pS. Type II activity is characterized by transient increases in bilayer conductance, up to a maximum of about 650 pS. Both type I and type II activities are voltage dependent. Channel activation occurs if the compartment containing mastoparan is held at a positive potential; channel inactivation if the same compartment is held at a negative potential. Channel formation is dependent on ionic strength; channel openings are only observed at KCl concentrations of 0.3 M or above. Furthermore, raising the concentration of KCl to 3.0 M stabilizes the open form of the channel. Mastoparan channels are weakly cation selective, P K/Cl ≈ 2. A 12-residue analogue, des -Ile 1 , Asn 2 mastoparan, preferentially forms type I channels. The ion channels formed by these short peptides may be modelled in terms of bundles of transmembrane α -helices.

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