A pace‐maker‐like current in the sheep atrium and its modulation by catecholamines.

A modified single‐sucrose‐gap system was used to study sheep atrial trabeculae under voltage‐clamp conditions and the magnitude of if was increased by theophylline, with a further increase by adrenaline, and the instantaneous fully activated current‐voltage relationship, i(E) was found to be linear in the activation range.