Persistence: a new statistic for characterizing ion-channel activity

1995 ◽  
Vol 350 (1334) ◽  
pp. 353-367 ◽  
Keyword(s):  
Patch Clamp ◽  
Ion Channel ◽  
Single Channel ◽  
Statistical Technique ◽  
Channel Activity ◽  
Patch Clamp Recording ◽  
Conductance Level

We introduce and illustrate by examples a new statistical technique, the persistence function, for characterizing ion-channel activity in a single-channel patch-clamp recording. Persistence is a function of both current and time. It is the probability that the current is at a given level (conditional on it having been at that level at an earlier time). Viewed as a function of current it exhibits the prominent conductance levels present in the recording, and viewed as a function of time for a conductance level it portrays the kinetics at that level.

Patch-Clamp Recording of Ion Channels: Interfering Effects of Patch Pipette Glass

Physiology ◽  
1990 ◽  
Vol 5 (4) ◽  
pp. 155-158
Author(s):  
C Zuazaga ◽  
A Steinacker
Keyword(s):  
Ion Channels ◽  
Patch Clamp ◽  
Ion Channel ◽  
Channel Activity ◽  
Patch Clamp Recording ◽  
Patch Clamp Technique ◽  
Clamp Technique ◽  
Ion Channel Properties ◽  
Patch Pipette ◽  
Channel Properties

Glass for pipettes used to record ion channel activity with the patch-clamp technique is selected on the basis of its electrical, thermal, and sealing properties. Recent findings stress a new characteristic to consider: the effect of pipette glass itself on ion channel properties.

A Silicon Nanopore Device for On-Chip Patch Clamp Measurements of Single Ion Channel Activity

2015 ◽  
Vol 1720 ◽  
Author(s):  
L. Plucinski ◽  
Y. Chen ◽  
G. L. Liu
Keyword(s):  
Cell Membrane ◽  
Patch Clamp ◽  
Ion Channel ◽  
High Resistance ◽  
Single Channel ◽  
Electrical Characterization ◽  
Channel Activity ◽  
Human Neuroblastoma ◽  
Access Resistance ◽  
On Chip

ABSTRACTHere we present a novel silicon nanopore planar patch clamp chip for single ion channel screening. We fabricate our devices using a combination of KOH and metal-assisted etching. Electrical characterization shows that the shunt capacitance and access resistance are within the accepted ranges for single channel recordings. In order to test our devices, we cultured and differentiated human neuroblastoma SH-SY5Y cells on chip. We reliably obtained a high resistance seal to the cell membrane and report single ion channel activity recordings.

scholarly journals TOK Homologue in Neurospora crassa: First Cloning and Functional Characterization of an Ion Channel in a Filamentous Fungus

2003 ◽  
Vol 2 (1) ◽  
pp. 181-190 ◽  
Author(s):  
Stephen K. Roberts
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Neurospora Crassa ◽  
Filamentous Fungus ◽  
Single Channel ◽  
Functional Characterization ◽  
Reversal Potential ◽  
Channel Activity ◽  
Biophysical Properties ◽  
Patch Clamp Technique

ABSTRACT In contrast to animal and plant cells, very little is known of ion channel function in fungal physiology. The life cycle of most fungi depends on the “filamentous” polarized growth of hyphal cells; however, no ion channels have been cloned from filamentous fungi and comparatively few preliminary recordings of ion channel activity have been made. In an attempt to gain an insight into the role of ion channels in fungal hyphal physiology, a homolog of the yeast K+ channel (ScTOK1) was cloned from the filamentous fungus, Neurospora crassa. The patch clamp technique was used to investigate the biophysical properties of the N. crassa K+ channel (NcTOKA) after heterologous expression of NcTOKA in yeast. NcTOKA mediated mainly time-dependent outward whole-cell currents, and the reversal potential of these currents indicated that it conducted K+ efflux. NcTOKA channel gating was sensitive to extracellular K+ such that channel activation was dependent on the reversal potential for K+. However, expression of NcTOKA was able to overcome the K+ auxotrophy of a yeast mutant missing the K+ uptake transporters TRK1 and TRK2, suggesting that NcTOKA also mediated K+ influx. Consistent with this, close inspection of NcTOKA-mediated currents revealed small inward K+ currents at potentials negative of EK. NcTOKA single-channel activity was characterized by rapid flickering between the open and closed states with a unitary conductance of 16 pS. NcTOKA was effectively blocked by extracellular Ca2+, verapamil, quinine, and TEA+ but was insensitive to Cs+, 4-aminopyridine, and glibenclamide. The physiological significance of NcTOKA is discussed in the context of its biophysical properties.

scholarly journals Ion channel activity in lobster skeletal muscle membrane

1993 ◽  
Vol 182 (1) ◽  
pp. 113-130
Author(s):  
M. K. Worden ◽  
R. Rahamimoff ◽  
E. A. Kravitz
Keyword(s):  
Ion Channel ◽  
Single Channel ◽  
Muscle Fibers ◽  
Muscle Membrane ◽  
Channel Activity ◽  
Experimental Conditions ◽  
Sarcolemmal Membrane ◽  
Excised Patches ◽  
Current Flows

Ion channel activity in the sarcolemmal membrane of muscle fibers is critical for regulating the excitability, and therefore the contractility, of muscle. To begin the characterization of the biophysical properties of the sarcolemmal membrane of lobster exoskeletal muscle fibers, recordings were made from excised patches of membrane from enzymatically induced muscle fiber blebs. Blebs formed as evaginations of the muscle sarcolemmal membrane and were sufficiently free of extracellular debris to allow the formation of gigaohm seals. Under simple experimental conditions using bi-ionic symmetrical recording solutions and maintained holding potentials, a variety of single channel types with conductances in the range 32–380 pS were detected. Two of these ion channel species are described in detail, both are cation channels selective for potassium. They can be distinguished from each other on the basis of their single-channel conductance and gating properties. The results suggest that current flows through a large number of ion channels that open spontaneously in bleb membranes in the absence of exogenous metabolites or hormones.

scholarly journals Characterization of ryanodine receptor type 1 single channel activity using “on-nucleus” patch clamp

Cell Calcium ◽  
2014 ◽  
Vol 56 (2) ◽  
pp. 96-107 ◽  
Author(s):  
Larry E. Wagner ◽  
Linda A. Groom ◽  
Robert T. Dirksen ◽  
David I. Yule
Keyword(s):  
Patch Clamp ◽  
Ryanodine Receptor ◽  
Single Channel ◽  
Receptor Type ◽  
Channel Activity ◽  
Single Channel Activity

Recording of single γ-aminobutyrate- and acetylcholine-activated receptor channels translated by exogenous mRNA in Xenopus oocytes

1983 ◽  
Vol 218 (1213) ◽  
pp. 481-484 ◽  
Keyword(s):  
High Resolution ◽  
Patch Clamp ◽  
Xenopus Oocytes ◽  
Optic Lobe ◽  
Single Channel ◽  
Patch Clamp Recording ◽  
Chick Optic Lobe ◽  
Single Channel Currents ◽  
Channel Currents

High resolution (‘giga-seal’) patch clamp recording in Xenopus oocytes was used to measure single channel currents from ACh- and GABA-activated receptors. The proteins that make up these receptors had been translated from mRNA derived from, respectively, denervated cat muscle and chick optic lobe.

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