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