Abstract
Cardiac pacemaker cells of the sino-atrial node are responsible for the initiation of the heart beat and express an array of ion channels. The patch-clamp technique is the gold standard method for investigating the function of ion channels expressed in electrically active cells. Conventional whole-cell and perforated patch-clamp techniques can be used to investigate ionic currents in the voltage-clamp mode and changes in membrane potential (e.g., action potential) in the current-clamp mode. Here, we provide details of protocols used to measure spontaneous and triggered action potentials and whole-cell funny current If (HCN4) in single cardiomyocytes isolated from the mouse sino-atrial node (SAN).