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Anosov AA, Smirnova EY, Korepanova EA, Kazamanov VA, Derunets AS. Different effects of two Poloxamers (L61 and F68) on the conductance of bilayer lipid membranes. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:14. [PMID: 36920579 DOI: 10.1140/epje/s10189-023-00270-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
The integral conductance of planar lipid bilayer membranes in the presence of two Poloxamers (Pluronics) L61 and F68 with the same lengths of hydrophobic poly(propylene oxide) blocks and the different lengths of hydrophilic poly(ethylene oxide) blocks increases with an increase in the concentration of both Pluronics; however, the shape of the conductance-concentration curves is super linear for L61 and sublinear for F68. In the presence of both Pluronics, rare discrete current jumps are observed against the background of continuous current. At high concentrations, the I-V curves of membranes with both L61 and F68 became nonlinear at sufficiently low voltages but differed significantly. At voltages greater than 50 mV, the conductance of membranes with L61 increased sharply and quantized jumps were observed toward higher conductance, which could be interpreted as the appearance of additional pores. On the contrary, the conductance of membranes with F68 decreased and quantized jumps to lower conductance were observed, which could be interpreted as blocking of already existing pores. We attributed the differences in the conductance-concentration and I-V curves of these two Pluronics to their different effects on the dynamics of membrane hydration and, accordingly, on the probability of formation of conducting pores.
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Affiliation(s)
- A A Anosov
- Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
- Kotelnikov Institute of Radioengineering and Electronics of RAS, Moscow, Russia
| | - E Yu Smirnova
- Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - E A Korepanova
- Pirogov Russian National Research Medical University, Moscow, Russia
| | - V A Kazamanov
- MIREA-Russian Technological University, Moscow, Russia
| | - A S Derunets
- National Research Center Kurchatov Institute, Moscow, Russia.
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Yang L, Pierce S, Gould TW, Craviso GL, Leblanc N. Ultrashort nanosecond electric pulses activate a conductance in bovine adrenal chromaffin cells that involves cation entry through TRPC and NALCN channels. Arch Biochem Biophys 2022; 723:109252. [DOI: 10.1016/j.abb.2022.109252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 03/25/2022] [Accepted: 04/12/2022] [Indexed: 12/14/2022]
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5 ns electric pulses induce Ca 2+-dependent exocytotic release of catecholamine from adrenal chromaffin cells. Bioelectrochemistry 2021; 140:107830. [PMID: 33965669 DOI: 10.1016/j.bioelechem.2021.107830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022]
Abstract
Previously we reported that adrenal chromaffin cells exposed to a 5 ns, 5 MV/m pulse release the catecholamines norepinephrine (NE) and epinephrine (EPI) in a Ca2+-dependent manner. Here we determined that NE and EPI release increased with pulse number (one versus five and ten pulses at 1 Hz), established that release occurs by exocytosis, and characterized the exocytotic response in real-time. Evidence of an exocytotic mechanism was the appearance of dopamine-β-hydroxylase on the plasma membrane, and the demonstration by total internal reflection fluorescence microscopy studies that a train of five or ten pulses at 1 Hz triggered the release of the fluorescent dye acridine orange from secretory granules. Release events were Ca2+-dependent, longer-lived relative to those evoked by nicotinic receptor stimulation, and occurred with a delay of several seconds despite an immediate rise in Ca2+. In complementary studies, cells labeled with the plasma membrane fluorescent dye FM 1-43 and exposed to a train of ten pulses at 1 Hz underwent Ca2+-dependent increases in FM 1-43 fluorescence indicative of granule fusion with the plasma membrane due to exocytosis. These results demonstrate the effectiveness of ultrashort electric pulses for stimulating catecholamine release, signifying their promise as a novel electrostimulation modality for neurosecretion.
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2-ns Electrostimulation of Ca 2+ Influx into Chromaffin Cells: Rapid Modulation by Field Reversal. Biophys J 2020; 120:556-567. [PMID: 33359835 PMCID: PMC7895993 DOI: 10.1016/j.bpj.2020.12.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/01/2020] [Accepted: 12/16/2020] [Indexed: 12/15/2022] Open
Abstract
Cellular effects of nanosecond-pulsed electric field exposures can be attenuated by an electric field reversal, a phenomenon called bipolar pulse cancellation. Our investigations of this phenomenon in neuroendocrine adrenal chromaffin cells show that a single 2-ns, 16 MV/m unipolar pulse elicited a rapid, transient rise in intracellular Ca2+ levels due to Ca2+ influx through voltage-gated calcium channels. The response was eliminated by a 2-ns bipolar pulse with positive and negative phases of equal duration and amplitude and fully restored (unipolar-equivalent response) when the delay between each phase of the bipolar pulse was 30 ns. Longer interphase intervals evoked Ca2+ responses that were greater in magnitude than those evoked by a unipolar pulse (stimulation). Cancellation was also observed when the amplitude of the second (negative) phase of the bipolar pulse was half that of the first (positive) phase but progressively lost as the amplitude of the second phase was incrementally increased above that of the first phase. When the amplitude of the second phase was twice that of the first phase, there was stimulation. By comparing the experimental results for each manipulation of the bipolar pulse waveform with analytical calculations of capacitive membrane charging/discharging, also known as accelerated membrane discharge mechanism, we show that the transition from cancellation to unipolar-equivalent stimulation broadly agrees with this model. Taken as a whole, our results demonstrate that electrostimulation of adrenal chromaffin cells with ultrashort pulses can be modulated with interphase intervals of tens of nanoseconds, a prediction of the accelerated membrane discharge mechanism not previously observed in other bipolar pulse cancellation studies. Such modulation of Ca2+ responses in a neural-type cell is promising for the potential use of nanosecond bipolar pulse technologies for remote electrostimulation applications for neuromodulation.
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Pakhomov AG, Pakhomova ON. The interplay of excitation and electroporation in nanosecond pulse stimulation. Bioelectrochemistry 2020; 136:107598. [PMID: 32711366 DOI: 10.1016/j.bioelechem.2020.107598] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/11/2022]
Abstract
Conventional electric stimuli of micro- and millisecond duration excite or activate cells at voltages 10-100 times below the electroporation threshold. This ratio is remarkably different for nanosecond electric pulses (nsEP), which caused excitation and activation only at or above the electroporation threshold in diverse cell lines, primary cardiomyocytes, neurons, and chromaffin cells. Depolarization to the excitation threshold often results from (or is assisted by) the loss of the resting membrane potential due to ion leaks across the membrane permeabilized by nsEP. Slow membrane resealing and the build-up of electroporation damages prevent repetitive excitation by nsEP. However, peripheral nerves and muscles are exempt from this rule and withstand multiple cycles of excitation by nsEP without the loss of function or signs of electroporation. We show that the damage-free excitation by nsEP may be enabled by the membrane charging time constant sufficiently large to (1) cap the peak transmembrane voltage during nsEP below the electroporation threshold, and (2) extend the post-nsEP depolarization long enough to activate voltage-gated ion channels. The low excitatory efficacy of nsEP compared to longer pulses makes them advantageous for medical applications where the neuromuscular excitation is an unwanted side effect, such as electroporation-based cancer and tissue ablation.
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Affiliation(s)
- Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA
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Yang L, Pierce S, Chatterjee I, Craviso GL, Leblanc N. Paradoxical effects on voltage-gated Na+ conductance in adrenal chromaffin cells by twin vs single high intensity nanosecond electric pulses. PLoS One 2020; 15:e0234114. [PMID: 32516325 PMCID: PMC7282663 DOI: 10.1371/journal.pone.0234114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 05/19/2020] [Indexed: 01/17/2023] Open
Abstract
We previously reported that a single 5 ns high intensity electric pulse (NEP) caused an E-field-dependent decrease in peak inward voltage-gated Na+ current (INa) in isolated bovine adrenal chromaffin cells. This study explored the effects of a pair of 5 ns pulses on INa recorded in the same cell type, and how varying the E-field amplitude and interval between the pulses altered its response. Regardless of the E-field strength (5 to 10 MV/m), twin NEPs having interpulse intervals ≥ than 5 s caused the inhibition of TTX-sensitive INa to approximately double relative to that produced by a single pulse. However, reducing the interval from 1 s to 10 ms between twin NEPs at E-fields of 5 and 8 MV/m but not 10 MV/m decreased the magnitude of the additive inhibitory effect by the second pulse in a pair on INa. The enhanced inhibitory effects of twin vs single NEPs on INa were not due to a shift in the voltage-dependence of steady-state activation and inactivation but were associated with a reduction in maximal Na+ conductance. Paradoxically, reducing the interval between twin NEPs at 5 or 8 MV/m but not 10 MV/m led to a progressive interval-dependent recovery of INa, which after 9 min exceeded the level of INa reached following the application of a single NEP. Disrupting lipid rafts by depleting membrane cholesterol with methyl-β-cyclodextrin enhanced the inhibitory effects of twin NEPs on INa and ablated the progressive recovery of this current at short twin pulse intervals, suggesting a complete dissociation of the inhibitory effects of twin NEPs on this current from their ability to stimulate its recovery. Our results suggest that in contrast to a single NEP, twin NEPs may influence membrane lipid rafts in a manner that enhances the trafficking of newly synthesized and/or recycling of endocytosed voltage-gated Na+ channels, thereby pointing to novel means to regulate ion channels in excitable cells.
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Affiliation(s)
- Lisha Yang
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
| | - Sophia Pierce
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
| | - Indira Chatterjee
- Department of Electrical and Biomedical Engineering, College of Engineering, University of Nevada, Reno, NV, United States of America
| | - Gale L. Craviso
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
| | - Normand Leblanc
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
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Probing Nanoelectroporation and Resealing of the Cell Membrane by the Entry of Ca 2+ and Ba 2+ Ions. Int J Mol Sci 2020; 21:ijms21093386. [PMID: 32403282 PMCID: PMC7247012 DOI: 10.3390/ijms21093386] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022] Open
Abstract
The principal bioeffect of the nanosecond pulsed electric field (nsPEF) is a lasting cell membrane permeabilization, which is often attributed to the formation of nanometer-sized pores. Such pores may be too small for detection by the uptake of fluorescent dyes. We tested if Ca2+, Cd2+, Zn2+, and Ba2+ ions can be used as nanoporation markers. Time-lapse imaging was performed in CHO, BPAE, and HEK cells loaded with Fluo-4, Calbryte, or Fluo-8 dyes. Ca2+ and Ba2+ did not change fluorescence in intact cells, whereas their entry after nsPEF increased fluorescence within <1 ms. The threshold for one 300-ns pulse was at 1.5–2 kV/cm, much lower than >7 kV/cm for the formation of larger pores that admitted YO-PRO-1, TO-PRO-3, or propidium dye into the cells. Ba2+ entry caused a gradual emission rise, which reached a stable level in 2 min or, with more intense nsPEF, kept rising steadily for at least 30 min. Ca2+ entry could elicit calcium-induced calcium release (CICR) followed by Ca2+ removal from the cytosol, which markedly affected the time course, polarity, amplitude, and the dose-dependence of fluorescence change. Both Ca2+ and Ba2+ proved as sensitive nanoporation markers, with Ba2+ being more reliable for monitoring membrane damage and resealing.
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Bagalkot TR, Leblanc N, Craviso GL. Stimulation or Cancellation of Ca 2+ Influx by Bipolar Nanosecond Pulsed Electric Fields in Adrenal Chromaffin Cells Can Be Achieved by Tuning Pulse Waveform. Sci Rep 2019; 9:11545. [PMID: 31395918 PMCID: PMC6687888 DOI: 10.1038/s41598-019-47929-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 07/26/2019] [Indexed: 12/30/2022] Open
Abstract
Exposing adrenal chromaffin cells to single 150 to 400 ns electric pulses triggers a rise in intracellular Ca2+ ([Ca2+]i) that is due to Ca2+ influx through voltage-gated Ca2+ channels (VGCC) and plasma membrane electropores. Immediate delivery of a second pulse of the opposite polarity in which the duration and amplitude were the same as the first pulse (a symmetrical bipolar pulse) or greater than the first pulse (an asymmetrical bipolar pulse) had a stimulatory effect, evoking larger Ca2+ responses than the corresponding unipolar pulse. Progressively decreasing the amplitude of the opposite polarity pulse while also increasing its duration converted stimulation to attenuation, which reached a maximum of 43% when the positive phase was 150 ns at 3.1 kV/cm, and the negative phase was 800 ns at 0.2 kV/cm. When VGCCs were blocked, Ca2+ responses evoked by asymmetrical and even symmetrical bipolar pulses were significantly reduced relative to those evoked by the corresponding unipolar pulse under the same conditions, indicating that attenuation involved mainly the portion of Ca2+ influx attributable to membrane electropermeabilization. Thus, by tuning the shape of the bipolar pulse, Ca2+ entry into chromaffin cells through electropores could be attenuated while preserving Ca2+ influx through VGCCs.
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Affiliation(s)
- Tarique R Bagalkot
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA.
| | - Normand Leblanc
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
| | - Gale L Craviso
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, 89557, USA
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Kotnik T, Rems L, Tarek M, Miklavčič D. Membrane Electroporation and Electropermeabilization: Mechanisms and Models. Annu Rev Biophys 2019; 48:63-91. [PMID: 30786231 DOI: 10.1146/annurev-biophys-052118-115451] [Citation(s) in RCA: 322] [Impact Index Per Article: 64.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Exposure of biological cells to high-voltage, short-duration electric pulses causes a transient increase in their plasma membrane permeability, allowing transmembrane transport of otherwise impermeant molecules. In recent years, large steps were made in the understanding of underlying events. Formation of aqueous pores in the lipid bilayer is now a widely recognized mechanism, but evidence is growing that changes to individual membrane lipids and proteins also contribute, substantiating the need for terminological distinction between electroporation and electropermeabilization. We first revisit experimental evidence for electrically induced membrane permeability, its correlation with transmembrane voltage, and continuum models of electropermeabilization that disregard the molecular-level structure and events. We then present insights from molecular-level modeling, particularly atomistic simulations that enhance understanding of pore formation, and evidence of chemical modifications of membrane lipids and functional modulation of membrane proteins affecting membrane permeability. Finally, we discuss the remaining challenges to our full understanding of electroporation and electropermeabilization.
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Affiliation(s)
- Tadej Kotnik
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; ,
| | - Lea Rems
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, 17165 Solna, Sweden;
| | - Mounir Tarek
- Université de Lorraine, CNRS, LPCT, F-54000 Nancy, France;
| | - Damijan Miklavčič
- Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia; ,
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Different Membrane Pathways Mediate Ca 2+ Influx in Adrenal Chromaffin Cells Exposed to 150-400 ns Electric Pulses. BIOMED RESEARCH INTERNATIONAL 2018; 2018:9046891. [PMID: 29789806 PMCID: PMC5896273 DOI: 10.1155/2018/9046891] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 02/18/2018] [Indexed: 12/21/2022]
Abstract
Exposing adrenal chromaffin cells to 5 ns electric pulses (nsPEF) causes a rapid rise in intracellular Ca2+ ([Ca2+]i) that is solely the result of Ca2+ influx through voltage-gated Ca2+ channels (VGCCs). This study explored the effect of longer duration nsPEF on [Ca2+]i. Single 150, 200, or 400 ns pulses at 3.1 kV/cm evoked rapid increases in [Ca2+]i, the magnitude of which increased linearly with pulse width and electric field amplitude. Recovery of [Ca2+]i to prestimulus levels was faster for 150 ns exposures. Regardless of pulse width, no rise in [Ca2+]i occurred in the absence of extracellular Ca2+, indicating that the source of Ca2+ was from outside the cell. Ca2+ responses evoked by a 150 ns pulse were inhibited to varying degrees by ω-agatoxin IVA, ω-conotoxin GVIA, nitrendipine or nimodipine, antagonists of P/Q-, N-, and L-type VGCCs, respectively, and by 67% when all four types of VGCCs were blocked simultaneously. The remaining Ca2+ influx insensitive to VGCC inhibitors was attributed to plasma membrane nanoporation, which comprised the E-field sensitive component of the response. Both pathways of Ca2+ entry were inhibited by 200 μM Cd2+. These results demonstrate that, in excitable chromaffin cells, single 150-400 ns pulses increased the permeability of the plasma membrane to Ca2+ in addition to causing Ca2+ influx via VGCCs.
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Burke RC, Bardet SM, Carr L, Romanenko S, Arnaud-Cormos D, Leveque P, O'Connor RP. Nanosecond pulsed electric fields depolarize transmembrane potential via voltage-gated K+, Ca2+ and TRPM8 channels in U87 glioblastoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2040-2050. [DOI: 10.1016/j.bbamem.2017.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 07/05/2017] [Accepted: 07/05/2017] [Indexed: 12/20/2022]
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Dielectric properties of isolated adrenal chromaffin cells determined by microfluidic impedance spectroscopy. Bioelectrochemistry 2017; 119:84-91. [PMID: 28918192 DOI: 10.1016/j.bioelechem.2017.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 01/07/2023]
Abstract
Knowledge of the dielectric properties of biological cells plays an important role in numerical models aimed at understanding how high intensity ultrashort nanosecond electric pulses affect the plasma membrane and the membranes of intracellular organelles. To this end, using electrical impedance spectroscopy, the dielectric properties of isolated, neuroendocrine adrenal chromaffin cells were obtained. Measured impedance data of the cell suspension, acquired between 1kHz and 20MHz, were fit into a combination of constant phase element and Cole-Cole models from which the effect of electrode polarization was extracted. The dielectric spectrum of each cell suspension was fit into a Maxwell-Wagner mixture model and the Clausius-Mossotti factor was obtained. Lastly, to extract the cellular dielectric parameters, the cell dielectric data were fit into a granular cell model representative of a chromaffin cell, which was based on the inclusion of secretory granules in the cytoplasm. Chromaffin cell parameters determined from this study were the cell and secretory granule membrane specific capacitance (1.22 and 7.10μF/cm2, respectively), the cytoplasmic conductivity, which excludes and includes the effect of intracellular membranous structures (1.14 and 0.49S/m, respectively), and the secretory granule milieu conductivity (0.35S/m). These measurements will be crucial for incorporating into numerical models aimed at understanding the differential poration effect of nanosecond electric pulses on chromaffin cell membranes.
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Adrenal Chromaffin Cells Exposed to 5-ns Pulses Require Higher Electric Fields to Porate Intracellular Membranes than the Plasma Membrane: An Experimental and Modeling Study. J Membr Biol 2017; 250:535-552. [PMID: 28840286 DOI: 10.1007/s00232-017-9983-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 08/19/2017] [Indexed: 12/17/2022]
Abstract
Nanosecond-duration electric pulses (NEPs) can permeabilize the endoplasmic reticulum (ER), causing release of Ca2+ into the cytoplasm. This study used experimentation coupled with numerical modeling to understand the lack of Ca2+ mobilization from Ca2+-storing organelles in catecholamine-secreting adrenal chromaffin cells exposed to 5-ns pulses. Fluorescence imaging determined a threshold electric (E) field of 8 MV/m for mobilizing intracellular Ca2+ whereas whole-cell recordings of membrane conductance determined a threshold E-field of 3 MV/m for causing plasma membrane permeabilization. In contrast, a 2D numerical model of a chromaffin cell, which was constructed with internal structures representing a nucleus, mitochondrion, ER, and secretory granule, predicted that exposing the cell to the same 5-ns pulse electroporated the plasma and ER membranes at the same E-field amplitude, 3-4 MV/m. Agreement of the numerical simulations with the experimental results was obtained only when the ER interior conductivity was 30-fold lower than that of the cytoplasm and the ER membrane permittivity was twice that of the plasma membrane. A more realistic intracellular geometry for chromaffin cells in which structures representing multiple secretory granules and an ER showed slight differences in the thresholds necessary to porate the membranes of the secretory granules. We conclude that more sophisticated cell models together with knowledge of accurate dielectric properties are needed to understand the effects of NEPs on intracellular membranes in chromaffin cells, information that will be important for elucidating how NEPs porate organelle membranes in other cell types having a similarly complex cytoplasmic ultrastructure.
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Li M, Xu X, Yang X, Kwong JSW, Shang H. The cardioprotective and antiarrhythmic effects of Nardostachys chinensis in animal and cell experiments. Altern Ther Health Med 2017; 17:398. [PMID: 28797251 PMCID: PMC5553922 DOI: 10.1186/s12906-017-1910-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 08/04/2017] [Indexed: 12/13/2022]
Abstract
Background Cardiovascular disease (CVD) is the leading cause of premature death throughout the world. An estimated 17.5 million people died from CVD in 2012, representing 31% of all global deaths. Nardostachys chinensis (NC), a typical traditional Chinese medicine (TCM), plays a crucial role in the management of patients with CVD, especially for those with cardiac arrhythmia. The purpose of this study was to evaluate the cardioprotective and antiarrhythmic effects of NC in animal and cell experiments. Methods To review the cardioprotective and antiarrhythmic effects of NC, studies of NC on cardiovascular diseases in animal and cell experiments were identified from five databases through April 2016. Two investigators independently conducted the literature search, study selection, and data extraction. Results A total of 16 studies were identified, including five animal experiments and eleven cell experiments. Four studies showed significant effects of NC on myocardial protection by inhibiting myocardial apoptosis, inflammation and oxidative stress. Twelve studies indicated significant beneficial effects of NC in cardiac arrhythmia primarily through the modulation of ion channels (Ik, Ik1, INa, ICa-L, Ito). Conclusion The above findings showed the possible efficacy of NC via its cardioprotective and antiarrhythmic effects, but the results should be interpreted with caution due to the limitations and the deficiencies in the studies.
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Yang L, Craviso GL, Vernier PT, Chatterjee I, Leblanc N. Nanosecond electric pulses differentially affect inward and outward currents in patch clamped adrenal chromaffin cells. PLoS One 2017; 12:e0181002. [PMID: 28700658 PMCID: PMC5507283 DOI: 10.1371/journal.pone.0181002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/23/2017] [Indexed: 11/18/2022] Open
Abstract
This study examined the effect of 5 ns electric pulses on macroscopic ionic currents in whole-cell voltage-clamped adrenal chromaffin cells. Current-voltage (I-V) relationships first established that the early peak inward current was primarily composed of a fast voltage-dependent Na+ current (INa), whereas the late outward current was composed of at least three ionic currents: a voltage-gated Ca2+ current (ICa), a Ca2+-activated K+ current (IK(Ca)), and a sustained voltage-dependent delayed rectifier K+ current (IKV). A constant-voltage step protocol was next used to monitor peak inward and late outward currents before and after cell exposure to a 5 ns pulse. A single pulse applied at an electric (E)-field amplitude of 5 MV/m resulted in an instantaneous decrease of ~4% in peak INa that then declined exponentially to a level that was ~85% of the initial level after 10 min. Increasing the E-field amplitude to 8 or 10 MV/m caused a twofold greater inhibitory effect on peak INa. The decrease in INa was not due to a change in either the steady-state inactivation or activation of the Na+ channel but instead was associated with a decrease in maximal Na+ conductance. Late outward current was not affected by a pulse applied at 5 MV/m. However, for a pulse applied at the higher E-field amplitudes of 8 and 10 MV/m, late outward current in some cells underwent a progressive ~22% decline over the course of the first 20 s following pulse exposure, with no further decline. The effect was most likely concentrated on ICa and IK(Ca) as IKV was not affected. The results of this study indicate that in whole-cell patch clamped adrenal chromaffin cells, a 5 ns pulse differentially inhibits specific voltage-gated ionic currents in a manner that can be manipulated by tuning E-field amplitude.
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Affiliation(s)
- Lisha Yang
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
| | - Gale L. Craviso
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
| | - P. Thomas Vernier
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, United States of America
| | - Indira Chatterjee
- Department of Electrical and Biomedical Engineering, College of Engineering, University of Nevada, Reno, NV, United States of America
| | - Normand Leblanc
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
- Center for Cardiovascular Research, University of Nevada, Reno School of Medicine, Reno, NV, United States of America
- * E-mail:
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