HCN1 channels
| Channel name | HCN11,2,3 |
| Description | Hyperpolarization-activated cyclic nucleotide-gated cation channel |
| Other names | HAC2, BCNG1 |
| Molecular information | Human: 890aa, NM_021072, NP_066550, chr. 5p12 |
| Rat: 910aa, NM_053375, NP_445827, chr. 2q15 | |
| Mouse: 910aa, NM_010408, NP_034538, chr. 13 D2.3 | |
| Associated subunits | Not established |
| Functional assays | Voltage-clamp |
| Current | Ih, If, or Iq |
| Conductance | Not established |
| Ion selectivity | K+, Na+ (PNa/PK ∼ 0.2); divalents do not permeate |
| Activation | V0.5 = -70 mV to -90 mV; ta = 30–300 ms at -140 mV to -95 mV (values are strongly influenced by experimental parameters such as temperature, pH, and pulse protocol) |
| Inactivation | No voltage-dependent inactivation |
| Activators | cAMP > cGMP (both induce a positive shift of V0.5 in the range of +2 to +7 mV) |
| Gating inhibitors | ZD7288 |
| Blockers | Cs+, ZD7288, ivabradine, zatebradine, cilobradine |
| Radioligands | None |
| Channel distribution | Central and peripheral neurones (hippocampus, cerebellum, neocortex, dorsal root ganglion, taste cells, photoreceptors), sinoatrial node cells |
| Physiological functions | Motor learning, spatial memory and plasticity, modulation of retinal light response, sour taste transduction |
| Mutations and pathophysiology | Not established in humans |
| Pharmacological significance | Not established |
aa, amino acids; chr., chromosome.
↵1. Ludwig A, Zong X, Jeglitsch M, Hofmann F, and Biel M (1998) A family of hyperpolarization-activated mammalian cation channels. Nature (Lond) 393:587-591
↵2. Monteggia LM, Eisch AJ, Tang MD, Kaczmarek LK, and Nestler EJ (2000) Cloning and localization of the hyperpolarization-activated cyclic nucleotide-gated channel family in rat brain. Brain Res Mol Brain Res 81:129-139
↵3. Santoro B, Liu DT, Yao H, Bartsch D, Kandel ER, Siegelbaum SA, and Tibbs GR (1998) Identification of a gene encoding a hyperpolarization-activated pacemaker channel of brain. Cell 93:717-729