Whole-cell patch clamp

Figure 13.3 Whole-cell patch-clamp recordings of excitatory postsynaptic currents (EPSCs) from dorsal horn neurons of rat (prenatal P2-13) spinal cord slices. The normal evoked EPSC of about 160pA obtained by focal stimulation of nearby tissue was dramatically reduced by addition of a cocktail (CABS) of CNQX 10 pM, D-APV 50 pM, bicuculline 10 pM and strychnine 5 pM to block glutamate, GABAa and glycine receptors. The small residual EPSC shown was blocked by the ATP P2 receptor antagonist suramin and is therefore probably mediated by released ATP. (Prom Bardoni et al. 1997 and reproduced by permission of the Journal of Neuroscience)...

The benzhydryl substituent is common to many reported N-type calcium channel blockers. A recently reported series derived from the neuroepileptic flunarizine (5), which exhibits N-type calcium channel potency in a whole-cell patch-clamp assay (IC50 0.08 iM) as well as L-type potency... 

The electrophysiological technique used to measure changes in membrane capacitance is the patch clamp [5,6] in the whole-cell recording mode, where the plasma membrane patch in the pipet is ruptured. In another configuration of the patch clamp, the plasma membrane patch is maintained intact. In this case, small currents due to the opening of individual channels can be measured in the membrane patch. The whole-cell patch clamp... 

McCarron The experiments we did involved whole cell patch-clamp studies. We were aware of the pH changes that may occur with CCCP so we buffered protons with 30 mM HEPES rather than the usual 10 mM. 

PIOL has previously been characterized as a partial agonist in whole-cell patch-clamp studies on cerebral cortical neurones and cultured hippocampal neurones (15,25). Only the methyl and ethyl analogs, 1 and 2, retained detectable ability to induce an agonist effect as shown on cultured cerebral cortical neurones and recombinant receptors (24). In the study of recombinant GABAa receptors, the weak responses of 1 and 2 were potentiated by simultaneously administered lorazepam and inhibited by the competitive antagonist SR 95531. 

In vitro Disaggregated cells Repolarizing currents (e.g., IKs, IK1, Ito), depolarizing currents (e.g., INa) currents, ICa (whole cell patch-clamp) Disaggregated cells ventricular myocytes mouse atrial tumor cells (AT-1) immortalized cardiac muscle cells (HL-1) Jost et al.,-65 Liu and Antzelevitch 66 Jurkiewicz and Sanguinetti 67 Li et al. 68 Yang and Roden 69 Banyasz et al. 70 Xia et al.71... 

APD (whole cell patch-clamp) Disaggregated cells Davie et al.72... 

Heterologous expression systems hERG current (whole cell patch clamp) Mammalian cell expression (CHO, HEK-293, mouse L-ceUs, COS-7) and Xenopus oocytes expression system Witchel et al. 77 Zou et al. 78 Cavero et al. 79 Martin et al. 80 McDonald et al.81... 

The Pfizer group in the United Kingdom has been actively involved in the search for new Class III antiarrhythmic agents. It has patented a variety of structural types that make extensive use of the methylsulphonylamino moiety. These include indanes [173,174], pyridines [175,176], piperazines [177-179], benzazepines [180], bisarylalkylamines [181] and diazabicyclic compounds [182], From this extensive work, two compounds, UK-66914 (65) and UK-68798 (66), have entered clinical trials. Compound (65) increases the effective refractory period (ERP) of ferret papillary muscle by 25% at a concentration of 0.5 //M [183]. Whole-cell patch-clamp studies... 

INTESTINE Characterization of a membrane potassium ion conductance in intestinal secretory cells using whole cell patch-clamp and calcium-sensitive dye techniques, 192, 309 isolation of intestinal epithelial cells and evaluation of transport functions, 192, 324 isolation of enterocyte membranes, 192, 341 established intestinal cell lines as model systems for electrolyte transport studies, 192, 354 sodium chloride transport pathways in intestinal membrane vesicles, 192, 389 advantages and limitations of vesicles for the characterization and the kinetic analysis of transport systems, 192, 409 isolation and reconstitution of the sodium-de-pendent glucose transporter, 192, 438 calcium transport by intestinal epithelial cell basolateral membrane, 192, 448 electrical measurements in large intestine (including cecum, colon, rectum), 192, 459... 

Bielik, N., Kocsis, P., Farkas, S. Whole-cell patch-clamp analysis of the effect of RGH-5002, a novel centrally acting muscle relaxant drug on voltage-gated sodium channels of dorsal root ganglion neurons, Naunyn Schmiedeberg s Arch. 1997, 356, Suppl 1, R25. 

Cui, C., Smith, D.O. and Adler, J. (1995) Characterization of mechanosensitive channels in Eschericia cofi cytoplasmic cell membrane by whole-cell patch clamp recording. Journal of Membrane Biology 144 31-42... 

Following whole-cell patch clamp with demonstration of stable hERG current, control values taken followed by exposure of the cells to the vehicle, then each concentration of the test article from lowest to highest concentration and finally the positive control... 

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