Patch-clamp studies of human cardiac ion channels in the evaluation of cardiac electrophysiological effects of compounds.

ABSTRACT

Drugs prolonging the QT interval appear to consistently inhibit the outward, rapid delayed rectifier K+ current (IKr) conveyed by the HERG channel. Hence, for determining whether a new drug candidate blocks the latter channel, this unit presents a basic electrophysiology protocol to conduct patch clamp studies in single cell preparations expressing heterologously cloned HERG channels. An additional protocol details the isolation of myocytes from specimens of human atria which are used in the study of native cardiac ion currents (INa, ICa, Ito, Isus, IK1). The results of these tests are useful for determining whether drug candidates have the desired cardiac safety profile for human use.