Heart rate reduction via selective 'funny' channel blockers.

The 'funny' current, first described in cardiac pacemaker cells almost 30 years ago, is a key player in the generation of pacemaker activity and the autonomic modulation of heart rate. Because of these specific functions, a search for molecules able to interfere selectively with the 'funny' current was undertaken soon after its discovery, with the aim of developing tools for the pharmacological control of heart rate. This search has succeeded in generating a new class of drugs, the heart rate-reducing agents, which act through specific blockade of f-channels; one of these drugs, ivabradine, is presently marketed against stable angina. Because of their many functions in heart and other tissues, pharmacological utilization of "funny" channel properties is an exciting new frontier open to further developments.