Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels, distributing in a variety of tissues, especially in excitable cells such as heart cells and many kinds of neurons, have an important role in the modulation of heart rate and neuronal excitability. Different from typical voltage-gated sodium channels and potassium channels, HCN channels were evoked inward currents when the cell was hyperpolarized. More and more recent studies have disclosed that HCN channels play important roles in the nervous system, which were linked with its special electrophysiological features as well as its regulatory effect on the cellular membrane excitability. HCN channels could be modulated by many factors including both extracellular molecules and intracellular signaling cascades, which made its functions complicated in the different condition. Based on its role, HCN channels are presumed to be a promising target for chronic pain and brain disorders. In this paper, we will focus on the advancement of roles of HCN channels in the neural system as well as its complex modulator factors.
Cyclic Nucleotide-Gated Cation Channels ; physiology ; Humans ; Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels ; physiology ; Membrane Potentials ; Neurons ; physiology ; Potassium Channels ; physiology

Hyperpolarization-activated and cyclic nucleotide-gated(HCN)channels which are distributed in a variety of tissues including excitable cells such as heart cells and different neurons have important functions in the control of heart rate and neuronal excitability. Unlike the typical potassium channels and sodium channels,HCN channels can evoke inward currents while the membrane potential is hyper-polarized. Some studies have discovered that HCN channels were important for the nervous system, due to their special electrophysiological features and regulatory effects on the cellular membrane excit-ability.HCN channels are modulated by such factors such as extracellular molecules and intracellular sig-naling cascades, which make their functions quite special in the brain. Given their role, HCN channels seem to be promising targets for specific brain disease as well as chronic pain.In this review,we focus on the roles and functions of HCN channels with their complex modulator factors and neural activity.