Flexoelectric effects in model and native membranes containing ion channels

Петров, А. Г.; Miller, Barbara A.; Hristova, Kalina; Usherwood, P.N.R.

doi:10.1007/bf00180263

Cited by 28 publications

(29 citation statements)

References 18 publications

(53 reference statements)

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“…One effect that can induce forces if the electric field causes polarization of the membrane is the so-called converse flexoelectricity (Petrov et al, 1993). The lipid bilayer of cell membranes contains charged proteins, which repel each other, influencing tension within the membrane.…”

Section: Discussionmentioning

confidence: 99%

Dynamic changes in traction forces with DC electric field in osteoblast-like cells

Curtze

Dembo

Miron

et al. 2004

Journal of Cell Science

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Primary bovine osteoblasts and human osteosarcoma cells exposed to direct-current electric fields undergo processes of retraction and elongation ultimately resulting in the realignment of the long cellular axis perpendicular to the electric field. The time taken for this reorientation was inversely correlated to field strength within a certain range. Cellular force output during reorientation was analyzed using a simple modification of traction force microscopy. The first detectable reaction was an increase in average traction force magnitude occurring between 10 and 30 seconds of electric field exposure. In the following 2 to 15 minutes traction forces at margins tangential to the electric field decreased below their initial values. Phase-contrast microscopy revealed elongating protrusions at these margins several minutes later. We could not correlate the initial traction changes with any change in intracellular free calcium levels measured using the fluorescent dye Fura-2 AM.

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Section: Discussionmentioning

confidence: 99%

Dynamic changes in traction forces with DC electric field in osteoblast-like cells

Curtze

Dembo

Miron

et al. 2004

Journal of Cell Science

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“…Perhaps voltage changes the adhesion of the membrane to the borosilicate glass at the site of seal formation or where the patch of membrane contacts the patch pipette, enabling membrane displacement and development of tension. Voltage-induced flexing of the membrane patch arising from the converse flexoelectric effect (28,30,33) might possibly contribute in some way toward moving the membrane or relaxing the contact between the membrane and the glass, allowing the membrane to move. There is also the possibility that cytoskeletal elements might be involved in some way.…”

Section: Discussionmentioning

confidence: 99%

Voltage-induced membrane displacement in patch pipettes activates mechanosensitive channels

Gil

Silberberg

Magleby

1999

Proc. Natl. Acad. Sci. U.S.A.

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The patch-clamp technique allows currents to be recorded through single ion channels in patches of cell membrane in the tips of glass pipettes. When recording, voltage is typically applied across the membrane patch to drive ions through open channels and to probe the voltage-sensitivity of channel activity. In this study, we used video microscopy and single-channel recording to show that prolonged depolarization of a membrane patch in borosilicate pipettes results in delayed slow displacement of the membrane into the pipette and that this displacement is associated with the activation of mechanosensitive (MS) channels in the same patch. The membrane displacement, Ϸ1 m with each prolonged depolarization, occurs after variable delays ranging from tens of milliseconds to many seconds and is correlated in time with activation of MS channels. Increasing the voltage step shortens both the delay to membrane displacement and the delay to activation. Preventing depolarization-induced membrane displacement by applying positive pressure to the shank of the pipette or by coating the tips of the borosilicate pipettes with soft glass prevents the depolarization-induced activation of MS channels. The correlation between depolarization-induced membrane displacement and activation of MS channels indicates that the membrane displacement is associated with sufficient membrane tension to activate MS channels. Because membrane tension can modulate the activity of various ligand and voltage-activated ion channels as well as some transporters, an apparent voltage dependence of a channel or transporter in a membrane patch in a borosilicate pipette may result from voltage-induced tension rather than from direct modulation by voltage. M echanosensitive (MS) ion channels can act as transducers for the senses of touch, hearing, balance, and proprioception and also seem to be involved in the regulation of cell volume (1-3). MS channels in patches of membrane in the tips of patch pipettes are readily activated when the membrane is stretched by the application of negative pressure to the shank of the patch pipette (4). The stretching of the membrane patch by negative pressure is thought to activate the channels by increased tension in the membrane (5). When the pressure is released, the channels then readily deactivate. In addition to stretch activation, some MS channels can also be activated by voltage (1). In this regard, depolarization of membrane patches from Xenopus oocytes activates endogenous MS channels in the patch after prolonged delays of typically 1-20 s (6). After stepping the voltage back to negative potentials, the MS channels then deactivate over several seconds. The delayed activation is observed for both on-cell and excised patches and typically occurs in a cooperative manner, with all channels activating over a short period of time compared with the duration of the delay to activation.We have shown recently that the delayed activation of the MS channels is not observed in outside-out patches, in membrane outside of the patc...

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“…In a bilayer membrane with two interfaces, a difference in tension between the interfaces can cause changes in curvature, an effect also known as converse¯exoelectricity. Both¯exoelectricity (current generation from bending) and its converse have been demonstrated in lipid bilayers 9 and cell membranes 10 .…”

mentioning

confidence: 97%

Voltage-induced membrane movement

Zhang

Keleshian

Sachs

2001

Nature

215

217

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Thermodynamics predicts that transmembrane voltage modulates membrane tension and that this will cause movement. The magnitude and polarity of movement is governed by cell stiffness and surface potentials. Here we confirm these predictions using the atomic force microscope to dynamically follow the movement of voltage-clamped HEK293 cells in different ionic-strength solutions. In normal saline, depolarization caused an outward movement, and at low ionic strength an inward movement. The amplitude was proportional to voltage (about 1 nm per 100 mV) and increased with indentation depth. A simple physical model of the membrane and tip provided an estimate of the external and internal surface charge densities (-5 x 10(-3) C x m(-2) and -18 x 10(-3) C x m(-2), respectively). Salicylate (a negative amphiphile) inhibited electromotility by increasing the external charge density by -15 x 10(-3) C x m(-2). As salicylate blocks electromotility in cochlear outer hair cells at the same concentration, the role of prestin as a motor protein may need to be reassessed.

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Flexoelectric effects in model and native membranes containing ion channels

Cited by 28 publications

References 18 publications

Dynamic changes in traction forces with DC electric field in osteoblast-like cells

Dynamic changes in traction forces with DC electric field in osteoblast-like cells

Voltage-induced membrane displacement in patch pipettes activates mechanosensitive channels

Voltage-induced membrane movement

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