Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2536590 | European Journal of Pharmacology | 2007 | 8 Pages |
The human ether-à-go-go related gene (HERG) encodes the α-subunit of a delayed rectifier potassium channel important in the repolarisation of the cardiac action potential. Excessive action potential prolongation through HERG channel inhibition is associated with a risk of torsade de pointes arrhythmias and is a major challenge for drug development. The acute effects of the novel prokinetic prucalopride were examined on heterologously expressed HERG channels in human embryonic kidney (HEK) 293 cells using the whole-cell patch–clamp technique. Prucalopride inhibited HERG channels in a concentration-dependent manner with an IC50 of 4.1 μM. Prucalopride significantly slowed channel deactivation and recovery from inactivation, accelerated and altered the extent of inactivation. Similar concentration-dependency and kinetic changes were observed with the minor T897 polymorphic HERG variant. Prucalopride block was frequency-independent due to rapid state-dependent block, with binding occurring in the open and inactivated states. Though prucalopride blocks HERG channels this is unlikely to be significant at clinically relevant concentrations.