Patch clamp electrode

Application of the two-electrode patch clamp arrangement in whole cell and on-cell configurations in a single colonic myocyte is shown in Fig. 1. In the experiments... 

Polar Cell Systems for Membrane Transport Studies Direct current electrical measurement in epithelia steady-state and transient analysis, 171, 607 impedance analysis in tight epithelia, 171, 628 electrical impedance analysis of leaky epithelia theory, techniques, and leak artifact problems, 171, 642 patch-clamp experiments in epithelia activation by hormones or neurotransmitters, 171, 663 ionic permeation mechanisms in epithelia biionic potentials, dilution potentials, conductances, and streaming potentials, 171, 678 use of ionophores in epithelia characterizing membrane properties, 171, 715 cultures as epithelial models porous-bottom culture dishes for studying transport and differentiation, 171, 736 volume regulation in epithelia experimental approaches, 171, 744 scanning electrode localization of transport pathways in epithelial tissues, 171, 792. 

Patch clamping requires that an electrode, housed within a micropipette, is attached to the cell to make an almost perfect seal with the cell membrane. This generates a very high resistance between the cell and the pipette wall, typically 10 CA2. The resulting transmembrane currents, measured between microelectrodes inside and outside the cell, generate extremely low noise so single channel events can be... 

Another important challenge that remains to be addressed is the relatively low success rate in obtaining useable and consistent high quality patch clamp data from most of these instruments. The success rate currently stands at around 40-60% for most systems [64], excluding the Ion Works Quattro that incorporates population patch clamping and claims a success rate of > 95% [53]. Some of the factors that contribute to this lack of success include stable positioning of the cells over the pore of the planar electrode, lack of adequate suction control in some cases, and the inability to achieve high resistance seals or electrical access. 

Since the 1970s, patch-clamp electrodes (electrodes placed inside a borosilicate glass pipet that is then heated and pulled, with its contents, to submicron-size diameters) have been used as micron-sized probes in elec-trophysiology experiments. Since 2000, single-walled and multiple-walled carbon nanotubes have been used as nanoelectrodes. 

Patch-clamping was developed in 1970 by Neher135 and Sakmann136 to study the electrochemistry inside cells, single-ion channels, and neurons A thin metal wire is inserted into a glass capillary, which is heated to shrink it around the wire, thus producing electrodes as small as 1 pm in diameter. 

Cummins It has been quite difficult for us to do an experiment hke this in a live cell, at least with the patch—clamp electrodes. The current runs down once you patch the cell. It is the hardest Na" " current I have ever worked with it disappears so quickly. This is why we did some of the computer modelling studies, to try to get an idea of what it might be doing. We need to go back and try to look and something hke that under tighter conditions. 

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