TISSUE CULTURE STUDY OF MURINE MUSCULAR DYSGENESIS: ROLE OF SPONTANEOUS ACTION POTENTIAL GENERATION IN THE REGULATION OF MUSCLE MATURATION

1979 ◽  
Vol 317 (1 Muscular Dyst) ◽  
pp. 550-570 ◽  
Author(s):  
Jeanne A. Powell ◽  
BethAnn Friedman ◽  
Aida Cossi
Keyword(s):  
Tissue Culture ◽  
Action Potential ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Culture Study ◽  
Spontaneous Action Potential ◽  
Spontaneous Action ◽  
Muscular Dysgenesis

P2559The mechanisms of spontaneous action potential generation in sinoauricular valve of the chick embryos

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Golovko ◽  
M Gonotkov ◽  
E Lebedeva
Keyword(s):  
Ion Channels ◽  
Action Potential ◽  
Ion Channel ◽  
Surrounding Tissue ◽  
Chick Embryos ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Generation Frequency ◽  
Spontaneous Action Potential ◽  
Spontaneous Action

Abstract Background The changes in the density of ion channels and/or damage of ion channel proteins violates the homeostasis of the potential forming ions in myocardium cells and may contribute to arrhythmogenesis. The study of ion channel function in embryos is important in order to understand the mechanisms of arrhythmia. The purpose of the present study was to identify the key ion channels that form action potentials (APs) in pacemaker cells in the area of the sinoauricular (SA) chicken embryo valve. Material and methods The embryos were removed from fertilized White Leghorn breed chicken eggs on the 10±1 day of incubation (ED10). The experiments were performed on freshly prepared strips (3 mm × 2 mm) of the right atrium, which included the left SA valve itself as well as the surrounding tissue. After that the APs were recorded from the area of left SA valve using the microelectrode technique. The functional analysis of ion channels was performed using the specific ion channel blockers. Results The strips generated APs with slow diastolic depolarization (SDD) and frequency from 132 to 251 impulses per min (ipm) (average - 177±22 ipm). The APs amplitude and dV/dtmax were 102±9 mV and 98±25 V/s (nstrips=49). At the third minute of exposure to E-4031 (1 μmol), a blocker of rapid outward K-current channels, IKr, the increase in the duration of the AP repolarization phase by 30% and the shortening of SDD by 20–25% (p<0.05; n=6) were registered. The APs generation frequency increased by 10%. Subsequently we observed the monotonic decrease in the AP amplitude due to the reduced overshoot and depolarized Emax. The electrical activity of all strips was blocked on the 20±2 min (Fig.1.a-c). Lidocaine (500 μmol), a blocker of Nav1.5 channels, increased a duration of SDD and APD90 twice, but decreased dV/dtmax by 2.5 times. The APs generation frequency decreased by 30% in comparison to the control. After 8±2 min exposure to lidocaine, the APs generation was blocked in 56% of samples. It is important to mention that in these strips right before the APs generation was blocked dV/dtmax was 30±15 V/s. In the samples, where the APs were not blocked after the exposure to lidocaine this parameter was 14±10 V/s (Fig. 1d-e). Nifedipine (10 μmol), a blocker of L-type Ca2+-channels, decreased APD90 by 56% and SDD by 25%. The APs generation frequency increased twice in comparison to the control samples (fig.1f-h). The chronotropic effects of nifedipine were dose-dependent. Nifedipine did not induce the blocking of APs generation. Figure 1. Effects of E-4031 (a-c), lidocaine (d-e) and nifedipine (e-g) on APs. Conclusions The received data demonstrate that the key role in the APs formation in ED10 embryos belong to the outward IKr and inward INa, but not to ICa,L. Thus, the mechanisms of spontaneous action potential generation in ED10 chick embryos have more in common with that in human iPSC-derived cardiomyocytes rather than in SA area cells of the ED11 mice embryos. Acknowledgement/Funding Rus fund Basic Research No. 18-34-00654; Project RAS No. 0415-2019-0006 and No. AAAA-A17-117012310152-2

The effect of acetylcholine on Characeae K+ channels at rest and during action potential generation

2012 ◽  
Vol 7 (6) ◽  
pp. 1066-1075 ◽  
Author(s):  
Vilma Kisnieriene ◽  
Tatiana Ditchenko ◽  
Anatoly Kudryashov ◽  
Vidmantas Sakalauskas ◽  
Vladimir Yurin ◽  
...  
Keyword(s):  
Action Potential ◽  
Transport System ◽  
Action Potential Generation ◽  
Potential Generation ◽  
K Channels ◽  
Potassium Ion Transport ◽  
Signalling Molecule ◽  
High Concentrations ◽  
Atpase Inhibition

AbstractThe role of acetylcholine (ACh) as a signalling molecule in plants was investigated using a model system of Characeae cells. The effect of ACh on conductance of K+ channels in Nitella flexilis cells and on the action potential generation in Nitellopsis obtusa cells after H+-ATPase inhibition, where repolarization occurs after the opening of outward rectifying K+ channels, was investigated. Voltage-clamp method based on only one electrode impalement was used to evaluate the activity of separate potassium ion transport system at rest. We found that ACh at high concentrations (1 mM and 5 mM) activates K+ channels as the main membrane transport system at the resting state involved in electrogenesis of Characeaen membrane potential. We observed that ACh caused an increase in duration of AP repolarization of cells in K+ state when plasmalemma electrical characteristics are determined by large conductance K+ channels irrespective of whether AP were spontaneous or electrically evoked. These results indicate interference of ACh with electrical cellular signalling pathway in plants.

Role of the prostanoid FP receptor in action potential generation and phenotypic transformation of NRK fibroblasts

2008 ◽  
Vol 20 (11) ◽  
pp. 2022-2029 ◽  
Author(s):  
W.H. Almirza ◽  
M.M. Dernison ◽  
P.H.J. Peters ◽  
E.J.J. van Zoelen ◽  
A.P.R. Theuvenet
Keyword(s):  
Action Potential ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Fp Receptor ◽  
Phenotypic Transformation

scholarly journals Curbing action potential generation or ATP-synthase leads to a decrease in in-cell pyruvate dehydrogenase activity in rat cerebrum slices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benjamin Grieb ◽  
Sivaranjan Uppala ◽  
Gal Sapir ◽  
David Shaul ◽  
J. Moshe Gomori ◽  
...  
Keyword(s):  
Action Potential ◽  
Atp Synthase ◽  
Neural Activity ◽  
Pyruvate Dehydrogenase ◽  
Cerebral Metabolism ◽  
Neuronal Firing ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Drastic Increase ◽  
Rat Cerebrum

AbstractDirect and real-time monitoring of cerebral metabolism exploiting the drastic increase in sensitivity of hyperpolarized 13C-labeled metabolites holds the potential to report on neural activity via in-cell metabolic indicators. Here, we followed the metabolic consequences of curbing action potential generation and ATP-synthase in rat cerebrum slices, induced by tetrodotoxin and oligomycin, respectively. The results suggest that pyruvate dehydrogenase (PDH) activity in the cerebrum is 4.4-fold higher when neuronal firing is unperturbed. The PDH activity was 7.4-fold reduced in the presence of oligomycin, and served as a pharmacological control for testing the ability to determine changes to PDH activity in viable cerebrum slices. These findings may open a path towards utilization of PDH activity, observed by magnetic resonance of hyperpolarized 13C-labeled pyruvate, as a reporter of neural activity.

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