Role of cortical cell type and morphology in subthreshold and suprathreshold uniform electric field stimulation in vitro

AbstractIn experimental research driven biomaterials science, the influence of different material properties (elastic stiffness, surface energy, etc.), and to a relatively lesser extent, the biophysical stimulation (electric/magnetic) on the cell-material interaction has been extensively investigated. Considering the central importance of the protein adsorption on cell-material interaction, the role of physiochemical factors on the protein adsorption is also probed. Despite its significance, the quantitative analysis of many such aspects remains largely unexplored in biomaterials science. In recent studies, the critical role of electric field stimulation towards modulation of cell functionality on implantable biomaterials has been experimentally demonstrated. Given this background, we investigated the influence of external electric field stimulation (upto 1.00 V/nm) on fibronectin (FN) adsorption on hydroxyapatite, HA (100) surface at 300K using all-atom MD simulation method. Fibronectin adsorption was found to be governed by the attractive electrostatic interaction, which changed with the electric field strength. Non-monotonous changes in structural integrity of fibronectin were recorded with the change in field strength and direction. This can be attributed to the spatial rearrangement of local charges and global structural changes of the protein. The dipole moment vectors of fibronectin, water and HA quantitatively exhibited similar pattern of orienting themselves parallel to the field direction, with field strength dependent increase in their magnitudes. No significant change has been recorded for radial distribution function of water surrounding fibronectin. Field dependent variation in the salt bridge nets and number of hydrogen bonds between fibronectin and hydroxyapatite were also examined. One of the important results in the context of the cell-material interaction is that the RGD sequence of FN was exposed to solvent side, when the field was applied along a direction outward perpendicular to HA (001) surface. Summarizing, the present study provides quantitative insights into the influence of electric field stimulation on biomolecular interactions involved in fibronectin adsorption on hydroxyapatite surface.

Download Full-text

Muscarinic receptor subtypes in canine trachea

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1990.258.6.l349 ◽

1990 ◽

Vol 258 (6) ◽

pp. L349-L354 ◽

Cited By ~ 2

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.

Download Full-text

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

Journal of Applied Physiology ◽

10.1152/jappl.1987.63.4.1558 ◽

1987 ◽

Vol 63 (4) ◽

pp. 1558-1566 ◽

Cited By ~ 27

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.

Download Full-text

Electric field stimulation for tissue engineering applications

BMC Biomedical Engineering ◽

10.1186/s42490-020-00046-0 ◽

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.

Download Full-text

Continual electric field stimulation preserves contractile function of adult ventricular myocytes in primary culture

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1994.266.1.h341 ◽

1994 ◽

Vol 266 (1) ◽

pp. H341-H349 ◽

Cited By ~ 24

Author(s):

H. J. Berger ◽

S. K. Prasad ◽

A. J. Davidoff ◽

D. Pimental ◽

O. Ellingsen ◽

...

Keyword(s):

Electric Field ◽

Primary Culture ◽

Ventricular Myocytes ◽

Contractile Function ◽

Isolated Heart ◽

Uniform Electric Field ◽

Field Stimulation ◽

Biophysical Parameters ◽

Ph Gradients ◽

Electric Field Stimulation

To model with greater fidelity the electromechanical function of freshly isolated heart muscle cells in primary culture, we describe a technique for the continual electrical stimulation of adult myocytes at physiological frequencies for several days. A reusable plastic cover was constructed to fit standard, disposable 175-cm2 tissue culture flasks and to hold parallel graphite electrodes along the long axis of each flask, which treated a uniform electric field that resulted in a capture efficiency of ventricular myocytes of 75–80%. Computer-controlled amplifiers were designed to be capable of driving a number of flasks concurrently, each containing up to 4 x 10(6) myocytes, over a range of stimulation frequencies (from 0.1 to 7.0 Hz) with reversal of electrode polarity after each stimulus to prevent the development of pH gradients around each electrode. Unlike quiescent, unstimulated myocytes, the amplitude of contraction, and velocities of shortening and relaxation did not change in myocytes paced at 3–5 Hz for up to 72 h. The maintenance of normal contractile function in paced myocytes required mechanical contraction per se, since paced myocytes that remained quiescent due to the inclusion of 2.5 microM verapamil in the culture medium for 48 h also exhibited a decline in contractility when paced after verapamil removal. Similarly, pacing increased peak calcium current compared with quiescent cells that had not been paced. Thus myocyte contraction at physiological frequencies induced by continual uniform electric field stimulation in short-term primary culture in defining medium maintains some biophysical parameters of myocyte phenotype that are similar to those observed in freshly isolated adult ventricular myocytes.

Download Full-text

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

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1987.253.2.h480 ◽

1987 ◽

Vol 253 (2) ◽

pp. H480-H486 ◽

Cited By ~ 8

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.

Download Full-text

Ih interacts with somato-dendritic structure to determine frequency response to weak alternating electric field stimulation

Journal of Neurophysiology ◽

10.1152/jn.00541.2017 ◽

2018 ◽

Vol 119 (3) ◽

pp. 1029-1036 ◽

Cited By ~ 9

Author(s):

Enrique H. S. Toloza ◽

Ehsan Negahbani ◽

Flavio Fröhlich

Keyword(s):

Electric Field ◽

Electric Fields ◽

Cellular Response ◽

Current Injection ◽

Field Stimulation ◽

Electric Field Stimulation ◽

Cation Current ◽

Network Oscillations ◽

Alternating Electric Field

Transcranial current stimulation (tCS) modulates brain dynamics using weak electric fields. Given the pathological changes in brain network oscillations in neurological and psychiatric illnesses, using alternating electric field waveforms that engage rhythmic activity has been proposed as a targeted, network-level treatment approach. Previous studies have investigated the effects of electric fields at the neuronal level. However, the biophysical basis of the cellular response to electric fields has remained limited. Here, we characterized the frequency-dependent response of different compartments in a layer V pyramidal neuron to exogenous electric fields to dissect the relative contributions of voltage-gated ion channels and neuronal morphology. Hyperpolarization-activated cation current (Ih) in the distal dendrites was the primary ionic mechanism shaping the model’s response to electric field stimulation and caused subthreshold resonance in the tuft at 20 ± 4 Hz. In contrast, subthreshold Ih-mediated resonance in response to local sinusoidal current injection was present in all model compartments at 11 ± 2 Hz. The frequencies of both resonance responses were modulated by Ih conductance density. We found that the difference in resonance frequency between the two stimulation types can be explained by the fact that exogenous electric fields simultaneously polarize the membrane potentials at the distal ends of the neuron (relative to field direction) in opposite directions. Our results highlight the role of Ih in shaping the cellular response to electric field stimulation and suggest that the common model of tCS as a weak somatic current injection fails to capture the cellular effects of electric field stimulation. NEW & NOTEWORTHY Modulation of cortical oscillation by brain stimulation serves as a tool to understand the causal role of network oscillations in behavior and is a potential treatment modality that engages impaired network oscillations in disorders of the central nervous system. To develop targeted stimulation paradigms, cellular-level effects must be understood. We demonstrate that hyperpolarization-activated cation current (Ih) and cell morphology cooperatively shape the response to applied alternating electric fields.

Download Full-text