Hyperpolarization-Activated HCN Pacemaker Channels: Role in the Brain, Heart and Disease
Sponsored by the APS Central Nervous System Section

The hyperpolarization-activated “pacemaker” channels, encoded by the HCN gene family, have been a bit of a mystery since they were first identified almost thirty years ago. These channels are thought to contribute to spontaneous pacemaker activity in both heart and certain neurons of the brain. The channels also contribute to the integration of excitatory and inhibitory synaptic transmission. The lack of specific, selective inhibitors has led to considerable controversy as to the role of these channels in neuronal and cardiac signaling. Several recent developments have greatly enhanced our understanding of the physiological and pathophysiological importance of the HCN channel family. First, mouse mutants lacking specific HCN subunits have been generated and analyzed at both a behavioral and electrophysiological level. These mutants show informative changes in both neural and cardiac function. Second, specific accessory proteins that interact with HCN subunits have been identified that may be important in regulating channel localization and function. Third, changes in HCN channel expression have been associated with patterns of neuronal activity that may contribute to both learning and memory and epilepsy. This symposium will present these recent developments in four talks that should be of timely interest to a wide audience in the fields of physiology, neuroscience and cardiovascular biology.