Queer current and pacemaker: The hyperpolarization-activated cation current in neurons

The cation conductance activated upon hyperpolarization of the membrane beyond the resting value appears to represent an ubiquitous type of membrane channel. Our understanding of the respective membrane current, termed I-h, in neurons has matured from that of a ''queer'' current toward that of a highly regulated mechanism that is particularly important in determining integrative behavior near rest and providing the pacemaker depolarization during rhythmic-oscillatory activity.