{'fraction_non_alphanumeric': 0.021473889702293802, 'fraction_numerical': 0.007808687164470474, 'mean_word_length': 5.06508875739645, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Investigating the CFTR Cl - Channel Using the Patch-Clamp Technique: An Overview

Patch-clamp recording is undoubtedly the leading method for studying the behaviour of ion channels. In 1976, Neher and Sakmann (1) first used the cell-attached configuration of the patch-clamp technique to resolve current flow through single acetylcholine-activated cation channels in frog skeletal muscle. Subsequent improvements to the technique produced a range of methods for the high resolution recording of current flow through ion channels in both intact cells and excised membrane patches (2). What makes the patch-clamp technique so powerful is its ability to resolve current flow through one or more ion channels in real time. A further strength of the technique is that many different types of ion channels in a wide variety of cell types are amenable to study. The ability of polished glass patch-pipettes to form extremely high resistance electrical seals (≥ 10 GΩ) with a cell membrane underlies the success of the patch-clamp technique. A high resistance seal reduces the background current noise to a level that permits the resolution of single-channel events with amplitude as small as 200 fA. Moreover, the mechanical stability of the seal between the patch-pipette and the cell membrane gives the technique its astonishing versatility. Membrane patches can be excised from cells to form either the excised inside-out or outside-out configurations. Alternatively, the membrane patch can be destroyed to establish the whole-cell configuration. The different configurations of the patch-clamp technique permit precise control of the composition of the solutions bathing either side of the cell membrane. As a result, the regulation of ion channels can be investigated simply by adding ion channel modulators into either the bath or pipette solutions while the selectivity of ion channels can determined by manipulating the ionic composition of these solutions. In 1988, Michael Gray and colleagues (3) identified a small conductance, cAMP-activated Cl