Hyperpolarization-activated, cyclic nucleotide-gated

Barco A, Alarcon JM, Kandel ER (2002) Expression of constitutively active CREB protein facilitates the late phase of long-term potentiation by enhancing synaptic capture. Cell 108 689-703 Bear MF, Malenka RC (1994) Synaptic plasticity LTP and LTD. Curr Opin Neurobiol 4 389-99 Bender RA, Brewster A, Santoro B, Ludwig A, Hofmann F, Biel M, Baram TZ (2001) Differential and age-dependent expression of hyperpolarization-activated, cyclic nucleotide-gated cation channel isoforms 1 1 suggests evolving roles in the developing rat hippocampus. Neuroscience 106 689-98... 

Sour taste detects acids, i.e., protons. Several different sour taste receptor candidates such as acid-sensing ion channels (ASICs) (57), hyperpolarization-activated cyclic nucleotide-gated channels (HCNs) (58), and two pore domain potassium channels (K2PS) (59, 60) have been described in the past. In addition, recent research identified two members of the polycystic kidney disease (PKD) family of the transient receptor potential superfamily (TRP) as strong sour taste receptor candidates or as part thereof. Immunohistochemistry and in situ hybridization revealed the presence of the polycystic-kidney-disease-like ion channel PKD2L1 in subsets of taste receptor cells of mouse fungiform, vallate, and foliate papillae. These cells differ from... 

In the myocardium, automaticity is the ability of the cardiac muscle to depolarize spontaneously (i.e., without external electrical stimulation from the autonomic nervous system). This spontaneous depolarization is due to the plasma membrane within the heart that has reduced permeability to potassium (K+) but still allows passive transfer of calcium ions, allowing a net charge to build. Automaticity is most often demonstrated in the sinoatrial (SA) node, the so-called pacemaker cells. Abnormalities in automaticity result in rhythm changes. The mechanism of automaticity involves the pacemaker channels of the HCN (Hyperpolarization-activated, Cyclic Nucleotide-gated) family14 (e.g., If, "funny" current). These poorly selective cation channels conduct more current as the membrane potential becomes more negative, or hyperpolarized. They conduct both potassium and sodium ions. The activity of these channels in the SA node cells causes the membrane potential to slowly become more positive (depolarized) until, eventually, calcium channels are activated and an action potential is initiated. 

Pachucki, J., Burmeister, L.A. and Larsen, P.R. (1999) Thyroid hormone regulates hyperpolarization-activated cyclic nucleotide-gated channel (HCN2) mRNA in the rat heart. Circulation Research, 85, 498-503. 

Cyclic nucleotide-modulated channels consist of two groups the cyclic nucleotide—gated (CNG) channels, which play key roles in sensory transduction for olfactory and photoreceptors, and the hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels. HCN channels are cation channels that open with hyperpolarization and close with depolarization upon direct binding of cyclic AMP or cyclic GMP, the activation curves for the channels are shifted to more hyper-polarized potentials. These channels play essential roles in cardiac pacemaker cells and presumably in rhythmically discharging neurons. 

Hyperpolarization-Activated Cyclic-Nucleotide-Gated Channels... 

Yeon K-Y, Chung G, Kim YH, Hwang JH, Davies AJ, Park M-K, Ahn DK, Kim JS, Jung SJ, Oh SB (2011) Eugenol reverses mechanical allodynia after peripheral nerve injury by inhibiting hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Pain 152 2108-2116... 

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels Potapova Potapova et al., 2004... 

Vasylyev, D. Lu, Q. Mark, B. Edward, K. Shan, Q. High-throughput screening of modulators of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. PCT Int. Appl. WO 2008121735, 2008 Chem. Abstr. 2008, 149, 455063. 

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