Microlesion formation in myocardial cells by high-intensity electric field stimulation

1987 ◽  
Vol 253 (2) ◽  
pp. H480-H486 ◽  
Author(s):  
J. L. Jones ◽  
R. E. Jones ◽  
G. Balasky
Keyword(s):  
Electric Field ◽  
High Intensity ◽  
Dielectric Breakdown ◽  
Fluorescein Isothiocyanate ◽  
Dependent Manner ◽  
Field Stimulation ◽  
Myocardial Cells ◽  
Electric Field Stimulation ◽  
Ionic Exchanges

Arrhythmias, S-T segment changes, immediate refibrillation, and other signs of dysfunction are often observed after clinical and experimental transthoracic defibrillation. In vitro studies suggested that shock-induced dysfunction is induced by sarcolemmal dielectric breakdown accompanied by ionic exchanges through transient, shock-induced microlesions in the sarcolemma. To test this hypothesis, cultured chick embryo myocardial cells were shocked in media containing fluorescein isothiocyanate-labeled dextrans (FITC-dextrans) ranging in molecular mass from 4 to 70 kDa, using electric field stimulation 5 ms in duration and ranging in intensity from 0 to 200 V/cm. Results showed that the percentage of cells incorporating 4- to 20-kDa dextrans increased in a dose-dependent manner. The 4- and 10-kDa dextrans were incorporated beginning at intensities of 50–100 V/cm. Dextran incorporation corresponded with shock intensities which produced a shock-induced arrest of spontaneous contraction lasting 1 min. The 20-kDa dextrans were incorporated following 150- and 200-V/cm shocks. Shocks of these intensities also produced a transient postshock contracture. Larger dextrans (40 and 70 kDa) were not incorporated. These results suggest the formation of transient sarcolemmal microlesions having a diameter of 45-60 A during high-intensity electric field stimulation.

Response of cultured myocardial cells to countershock-type electric field stimulation

1978 ◽  
Vol 235 (2) ◽  
pp. H214-H222 ◽  
Author(s):  
J. L. Jones ◽  
E. Lepeschkin ◽  
R. E. Jones ◽  
S. Rush
Keyword(s):  
Cell Membrane ◽  
Electric Field ◽  
Field Stimulation ◽  
Myocardial Cells ◽  
Adult Type ◽  
Electric Field Stimulation ◽  
Electric Countershock ◽  
Mechanical Responses ◽  
Single Response

Myocardial cells isolated from 8-day chick embryos were grown in monolayer culture under conditions that produce “standard embryonic” and “adult-type” cells. These cells were subjected to electric field stimulation that had a waveshape and intensities similar to those used in clinical electric countershock procedures. Photocell mechanograms obtained before, during, and after stimulation were correlated with simultaneously measured transmembrane potentials to determine the relationship between membrane polarization and arrhythmia production that occured after the stimulus. The results of these experiments demonstrate that a predictable sequence of mechanical responses occurs after stimuli ranging in intensity from 6 to 200 V/cm. This sequence, which closely resembles that observed in vivo after similar stimulation intensities, consists of a single response (activation), tachyarrhythmia, relaxed arrest followed by transient tachyarrhythmia, arrest with contracture, and cellular fibrillation. This diverse pattern of arrhythmias is associated with a prolonged depolarization of the cell membrane which increases with the intensity of the applied stimulus. It is probable that this depolarization is caused by a transient electromechanical deformation of the cell membrane during the shock. These findings contribute to a better understanding of the causes of the arrhythmias that appear after clinical and experimental electric countershock procedures.

Muscarinic receptor subtypes in canine trachea

1990 ◽  
Vol 258 (6) ◽  
pp. L349-L354 ◽  
Author(s):  
J. F. Brichant ◽  
D. O. Warner ◽  
S. J. Gunst ◽  
K. Rehder
Keyword(s):  
Electric Field ◽  
Muscarinic Receptor ◽  
Contractile Response ◽  
Receptor Subtypes ◽  
Field Stimulation ◽  
Muscarinic Receptor Subtypes ◽  
Electric Field Stimulation ◽  
M3 Receptors ◽  
M3 Subtype

Prejunctional and postjunctional muscarinic receptor subtypes were characterized in canine trachealis muscle strips. In vitro contractile responses of muscle strips to acetylcholine or electric field stimulation were determined in the absence and the presence of gallamine, pirenzepine, and 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP). Gallamine had no effect on the contractile response to acetylcholine but enhanced the contractile response to electric field stimulation. Pirenzepine and 4-DAMP reduced the contractile response to acetylcholine and electric field stimulation. The pA2 value for pirenzepine vs. acetylcholine [7.18 +/- 0.59 (SD)] was consistent with the affinity of pirenzepine for M2 or M3-receptors; whereas the pA2 value for 4-DAMP vs. acetylcholine (8.92 +/- 0.42) and the extremely low affinity of gallamine indicated postjunctional muscarinic receptors of the M3 subtype. The enhancement of the contractile response to electric field stimulation by gallamine suggested the presence of M2-prejunctional receptors.

Nonneural components in the response of fresh human airways to electric field stimulation

1987 ◽  
Vol 63 (4) ◽  
pp. 1558-1566 ◽  
Author(s):  
J. C. De Jongste ◽  
H. Mons ◽  
I. L. Bonta ◽  
K. F. Kerrebijn
Keyword(s):  
Electric Field ◽  
Time Course ◽  
Adrenergic Nerve ◽  
Organ Bath ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Small Peak ◽  
Antiasthmatic Drug ◽  
Human Bronchi

Fresh human bronchi, obtained at thoracotomy and maintained at 37 degrees C, were studied in vitro to investigate their response to electric field stimulation (EFS). We found complex responses that were not only composed of a rapid initial nerve-mediated cholinergic contraction and a non-adrenergic nerve-mediated relaxation, but, in 80% of preparations, also of a tonic contraction with a sustained time course. This sustained phase was not blocked by the nervous conductance blocker tetrodotoxin (TTX) and was therefore not neurally mediated. Controlled transient cooling to 4 degrees C in the organ bath reduced this sustained phase selectively for several hours. The leukotriene (LT) antagonist FPL 55712, dexamethasone, which inhibits phospholipase A2, and the antiasthmatic drug cromolyn all reduced the sustained phase significantly. In 20% of strips, an additional TTX-resistant contraction was seen directly after the cholinergic phase. This contraction could be inhibited by indomethacin. A similar small peak sometimes appeared after selective blocking of either the cholinergic or the sustained phases. Experiments in which the epithelium was removed from the strips suggested that this indomethacin-sensitive response, but not the sustained phase, was dependent on the presence of epithelium. These results show that EFS of fresh human bronchi stimulated cholinergic and nonadrenergic inhibitory nerves and gave rise to a partly epithelium-dependent synthesis of arachidonic acid metabolites, which caused contractile responses that interfered with the neurally mediated responses.

scholarly journals Electric field stimulation for tissue engineering applications

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Christina N. M. Ryan ◽  
Meletios N. Doulgkeroglou ◽  
Dimitrios I. Zeugolis
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Electric Field ◽  
Electric Fields ◽  
Cell Types ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Physiological Processes ◽  
Different Cell Types

AbstractElectric fields are involved in numerous physiological processes, including directional embryonic development and wound healing following injury. To study these processes in vitro and/or to harness electric field stimulation as a biophysical environmental cue for organised tissue engineering strategies various electric field stimulation systems have been developed. These systems are overall similar in design and have been shown to influence morphology, orientation, migration and phenotype of several different cell types. This review discusses different electric field stimulation setups and their effect on cell response.

Effects of imidazolines on neurogenic contraction in isolated urinary bladder detrusor strips from rabbit

2012 ◽  
Vol 90 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Hong-Mei He ◽  
Lei-Ming Ren ◽  
He-Lin Tian ◽  
Hai-Gang Lu ◽  
Ding Zhao
Keyword(s):  
Urinary Bladder ◽  
Electric Field ◽  
Antihypertensive Drugs ◽  
Purinergic Receptor ◽  
Dependent Manner ◽  
Field Stimulation ◽  
Concentration Dependent Manner ◽  
Electric Field Stimulation ◽  
Dependent Inhibition ◽  
Bladder Detrusor

Moxonidine and clonidine, which are imidazoline compounds, are sympathetic modulators used as centrally acting antihypertensive drugs. Moxonidine, clonidine, and agmatine produce extensive effects in mammalian tissues via imidazoline recognition sites (or receptors) or α2-adrenoceptors. To investigate the effects of imidazolines on the function of the urinary bladder, we tested the effects of moxonidine, clonidine, and agmatine on the neurogenic contraction induced by electric field stimulation, and on the post-synaptic receptors in isolated urinary bladder detrusor strips from rabbit. Both moxonidine at 1.0–10.0 µmol/L and clonidine at 0.1–10.0 µmol/L inhibited electric-field-stimulation-induced contraction in a concentration-dependent manner, but not agmatine (10.0–1000.0 µmol/L). Both moxonidine and clonidine failed to affect carbachol or adenosine-triphosphate-induced contractions; however, 1000.0 µmol/L agmatine significantly increased these contractions. Our study indicates that (i) moxonidine and clonidine produce a concentration-dependent inhibition of the neurogenic contractile responses to electric field stimulation in isolated detrusor strips from male New Zealand rabbits; (ii) post-synaptic muscarinic receptor and purinergic receptor stimulation are not involved in the responses of moxinidine and clonidine in this study; (iii) the inhibitory effects of these agents are probably not mediated by presynaptic imidazoline receptors.

Electric Field Stimulation of Delayed Fluorescence in Dry Films of Chloroplasts and Subchloroplast Particles Enriched in PSII

1979 ◽  
Vol 174 (2) ◽  
pp. 85-91 ◽  
Author(s):  
T.V. Ortoidze ◽  
Galina P. Borisevitch ◽  
P.S. Venediktov ◽  
A.A. Kononenko ◽  
D.N. Matorin ◽  
...  
Keyword(s):  
Electric Field ◽  
Delayed Fluorescence ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Stimulation Of
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