Patch-clamp studies using recombinant cells expressing hERG channels

2 Patch-clamp studies using recombinant cells expressing hERG channels 

Most pharmaceuticals associated with torsades de pointes inhibit rapidly delayed rectifier current, 1, . Therefore particular attention to assays for Iki is prudent for assessing risk of QT interval prolongation [32], 

Using the voltage-clamp technique, outward or inward ionic currents can be measured from single cell preparations. Because of inherent difficulties associated with recordingin native myocytes, much of the available data for this current has been obtained using recombinant cell lines expressing hERG. 

Inhibition of other outward (repolarizing) cmrents (e.g., I,q, I, or increase in inward (depolarizing) ionic currents (e.g., InJ could also lead to QT interval prolongation and, therefore, should be considered when investigating the mechanism(s) for QT interval prolongation [33-35]. 

When transfected with hERG alone or hERG in association with genes for potential regulating subunits (e.g., MiRPl), appropriate cell systems express a K+ channel that displays biophysical and pharmacological properties similar to Ikj. Several expression systems have been used to test the activity of test substances on hERG current. 

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