Correlation of open cell-attached and excised patch clamp techniques |
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Authors: | D Filipovic J P Hayslett |
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Institution: | (1) Department of Internal Medicine, Section of Nephrology, Yale School of Medicine, New Haven, CT |
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Abstract: | The excised patch clamp configuration provides a unique technique for some types of single channel analyses, but maintenance of stable, long-lasting preparations may be confounded by rundown and/or rapid loss of seal. Studies were performed on the amiloride-sensitive Na+ channel, located on the apical surface of A6 cells, to determine whether the nystatininduced open cell-attached patch could serve as an alternative configuration.Compared to excised inside-out patches, stable preparations were achieved more readily with the open cell-attached patch (9% vs. 56% of attempts). In both preparations, the current voltage (I-V) relation was linear, current amplitudes were equal at opposite equivalent clamped voltages, and E
rev was zero in symmetrical Na+ solutions, indicating similar Na+ activities on the cytosolic and external surfaces of the patch. Moreover, there was no evidence that nystatin altered channel activity in the patch because slope conductance (3–4pS) and E
rev (75 mV), when the bath was perfused with a high K:low Na solution (E
Na=80 mV), were nearly equal in both patch configurations.Our results therefore indicate that the nystatininduced open cell-attached patch can serve as an alternative approach to the excised inside-out patch when experiments require modulation of univalent ions in the cytosol.We thank Dr. Olaf S. Andersen for his suggestions in the development of the open cell-attached recording technique. This work was supported by a National Institutes of Health grant (DK-18061) |
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Keywords: | A6 cells Epithelial Na+ channels Open cell-attached patches Nystatin |
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