Manual Whole-Cell Patch-Clamping of the HERG Cardiac K+ Channel

Delayed ventricular repolarization, as measured by a prolongation of the QT interval on the electrocardiogram, is a major safety issue in the drug development process. It is now recognized that most cases of drug-induced QT prolongation arise from direct pharmacological inhibition of the human ether-a-go-go- related gene (HERG) cardiac K⁺ channel. It is standard practice to test a drug’s ability to interact with the HERG channel prior to entry into clinical trials. This testing is used, as part of a larger battery of tests, to help predict the cardiac safety profile of a drug. Manual whole-cell patch-clamping provides the most sensitive and accurate way to examine the biophysical and pharmacological properties of the HERG cardiac K⁺ channel.