scholarly journals Electrophysiological measurement of ion channels on plasma/organelle membranes using an on-chip lipid bilayer system

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Koki Kamiya ◽  
Toshihisa Osaki ◽  
Kenji Nakao ◽  
Ryuji Kawano ◽  
Satoshi Fujii ◽  
...  
Keyword(s):  
Ion Channels ◽  
Lipid Bilayer ◽  
Bilayer System ◽  
Electrophysiological Measurement ◽  
On Chip

scholarly journals Development of an automated system to measure ion channel currents using a surface-modified gold probe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Minako Hirano ◽  
Masahisa Tomita ◽  
Chikako Takahashi ◽  
Nobuyuki Kawashima ◽  
Toru Ide
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Lipid Bilayer ◽  
Measurement System ◽  
Automated System ◽  
Channel Activity ◽  
Channel Current ◽  
Gold Probe ◽  
Measurement Efficiency ◽  
Channel Currents

AbstractArtificial lipid bilayer single-channel recording technique has been employed to determine the biophysical and pharmacological properties of various ion channels. However, its measurement efficiency is very low, as it requires two time-consuming processes: preparation of lipid bilayer membranes and incorporation of ion channels into the membranes. In order to address these problems, we previously developed a technique based on hydrophilically modified gold probes on which are immobilized ion channels that can be promptly incorporated into the bilayer membrane at the same time as the membrane is formed on the probes’ hydrophilic area. Here, we improved further this technique by optimizing the gold probe and developed an automated channel current measurement system. We found that use of probes with rounded tips enhanced the efficiency of channel current measurements, and introducing a hydrophobic area on the probe surface, beside the hydrophilic one, further increased measurement efficiency by boosting membrane stability. Moreover, we developed an automated measurement system using the optimized probes; it enabled us to automatically measure channel currents and analyze the effects of a blocker on channel activity. Our study will contribute to the development of high-throughput devices to identify drug candidates affecting ion channel activity.

Rotational behaviour of PEGylated gold nanorods in a lipid bilayer system

2016 ◽  
Vol 115 (9-12) ◽  
pp. 1122-1143 ◽  
Author(s):  
Priyanka A. Oroskar ◽  
Cynthia J. Jameson ◽  
Sohail Murad
Keyword(s):  
Lipid Bilayer ◽  
Gold Nanorods ◽  
Rotational Behaviour ◽  
Bilayer System

scholarly journals Common evolutionary origins of mechanosensitive ion channels in Archaea, Bacteria and cell-walled Eukarya

Archaea ◽  
2002 ◽  
Vol 1 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Anna Kloda ◽  
Boris Martinac
Keyword(s):  
Ion Channels ◽  
Lipid Bilayer ◽  
Sequence Homology ◽  
Eukaryotic Cell ◽  
Physiological Functions ◽  
Ancestral Origin ◽  
Gating Mechanisms ◽  
Evolutionary Origins ◽  
Osmotic Challenge ◽  
Small Conductance

The ubiquity of mechanosensitive (MS) channels triggered a search for their functional homologs in Archaea. Archaeal MS channels were found to share a common ancestral origin with bacterial MS channels of large and small conductance, and sequence homology with several proteins that most likely function as MS ion channels in prokaryotic and eukaryotic cell-walled organisms. Although bacterial and archaeal MS channels differ in conductive and mechanosensitive properties, they share similar gating mechanisms triggered by mechanical force transmitted via the lipid bilayer. In this review, we suggest that MS channels of Archaea can bridge the evolutionary gap between bacterial and eukaryotic MS channels, and that MS channels of Bacteria, Archaea and cell-walled Eukarya may serve similar physiological functions and may have evolved to protect the fragile cellular membranes in these organisms from excessive dilation and rupture upon osmotic challenge.

scholarly journals Distance measurements reveal a common topology of prokaryotic voltage-gated ion channels in the lipid bilayer

2006 ◽  
Vol 103 (43) ◽  
pp. 15865-15870 ◽  
Author(s):  
J. Richardson ◽  
R. Blunck ◽  
P. Ge ◽  
P. R. Selvin ◽  
F. Bezanilla ◽  
...  
Keyword(s):  
Ion Channels ◽  
Lipid Bilayer ◽  
Distance Measurements ◽  
Voltage Gated ◽  
Voltage Gated Ion Channels ◽  
Gated Ion Channels

scholarly journals Association of Model Neurotransmitters with Lipid Bilayer Membranes

2019 ◽  
Author(s):  
B. Josey ◽  
F. Heinrich ◽  
V. Silin ◽  
M. Lösche
Keyword(s):  
Surface Plasmon Resonance ◽  
Ion Channels ◽  
Lipid Bilayer ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Dissociation Constants ◽  
Measurement Techniques ◽  
Neutron Reflectometry ◽  
Membrane Association ◽  
Lipid Bilayer Membranes

AbstractAimed to reproduce the results of electrophysiological studies of synaptic signal transduction, conventional models of neurotransmission are based on the specific binding of neurotransmitters to ligand-gated receptor ion channels. However, the complex kinetic behavior observed in synaptic transmission cannot be reproduced in a standard kinetic model without the ad hoc postulation of additional conformational channel states. On the other hand, if one invokes unspecific neuro-transmitter adsorption to the bilayer—a process not considered in the established models—the electrophysiological data can be rationalized with only the standard set of three conformational receptor states that also depend on this indirect coupling of neurotransmitters via their membrane interaction. Experimental verification has been difficult because binding affinities of neuro-transmitters to the lipid bilayer are low. We quantify this interaction with surface plasmon resonance to measure equilibrium dissociation constants in neurotransmitter membrane association. Neutron reflectometry on artificial membranes reveals the structural aspects of neurotransmitters association with zwitterionic and anionic bilayers. We establish that serotonin interacts non-specifically with the membrane at physiologically relevant concentrations whilst GABA (γ-aminobutyric acid) does not. Surface plasmon resonance shows that serotonin adsorbs with millimolar affinity and neutron reflectometry shows that it penetrates the membrane deeply whereas GABA is excluded from the bilayer.SignificanceReceptor ion channels in the postsynaptic membrane and their neurotransmitter agonists enable fast communication between neuronal cells. Electrophysiology studies reveal surprisingly complex kinetics that apparently require a variety of protein conformational states for their quantitative interpretation, but an alternate hypothesis invoking neurotransmitter membrane association reduces the complexity of the underlying reaction schemes significantly. While their affinity may be low, and is hard to quantify experimentally, neurotransmitter membrane association can be relevant because of their large temporary concentration in the synaptic cleft. With thermodynamic and structural measurements we quantify membrane-bound states of serotonin, establishing this neurotransmitter as membrane-affine, whereas the affinity of the more hydrophilic GABA is too low to register in our sensitivity-optimized measurement techniques.

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