Cited by 143Ion channel regulation and functionCardiac electrophysiology and arrhythmiasIon Transport and Channel Regulation

The Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: From Biophysics to Pharmacology of a Unique Family of Ion Channels

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Sartiani, Laura, Mannaioni, Guido, Masi, Alessio, Novella Romanelli, Maria, Cerbai, Elisabetta·2017·Pharmacological Reviews

Abstract

Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels are important members of the voltage-gated pore loop channels family. They show unique features: they open at hyperpolarizing potential, carry a mixed Na/K current, and are regulated by cyclic nucleotides. Four different isoforms have been cloned (HCN1-4) that can assemble to form homo- or heterotetramers, characterized by different biophysical properties. These proteins are widely distributed throughout the body and involved in different physiologic processes, the most important being the generation of spontaneous electrical activity in the heart and the regulation of synaptic transmission in the brain. Their role in heart rate, neuronal pacemaking, dendritic integration, learning and memory, and visual and pain perceptions has been extensively studied; these channels have been found also in some peripheral tissues, where their functions still need to be fully elucidated. Genetic defects and altered expression of HCN channels are linked to several pathologies, which makes these proteins attractive targets for translational research; at the moment only one drug (ivabradine), which specifically blocks the hyperpolarization-activated current, is clinically available. This review discusses current knowledge about HCN channels, starting from their biophysical properties, origin, and developmental features, to (patho)physiologic role in different tissues and pharmacological modulation, ending with their present and future relevance as drug targets.

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Crossref · 10.1124/pr.117.014035

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  • Dysregulated HCN signaling alters resonance and timing, contributing to network states linked to mood and executive symptoms.

    “Dysregulated HCN signaling alters resonance and timing, contributing to network states linked to mood and executive symptoms, whereas targeted modulation promises restoration of frequency-specific gain without sacrificing the dynamical flexibility essential for adaptive cognition [272,277].”

    From Synaptic Plasticity—Intrinsic Excitability and Antidepressant Discovery (2026) · cites this paper as [277]

    The sections on Resonance Properties and Rhythmogenesis say HCN channels shape frequency preference and oscillation timing. The sections on Mood Disorders and Schizophrenia link altered HCN activity to depression-related behavior and impaired prefrontal working memory, respectively. The paper does not establish that altered resonance or timing is the mechanism connecting HCN dysregulation to those mood and executive effects. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • Many isoform-preferring HCN tools have incomplete pharmacokinetic and off-target profiling, resulting in narrow therapeutic windows and variable central effects.

    “many “isoform-preferring” tools have incomplete pharmacokinetic and off-target profiling, resulting in narrow therapeutic windows and variable central effects [277,298]”

    From Synaptic Plasticity—Intrinsic Excitability and Antidepressant Discovery (2026) · cites this paper as [277]

    The section “Isoform-Selective HCN Blockers” (page unavailable) describes isoform-preferring compounds and warns that amiodarone’s effects on multiple ion channels may obscure its selectivity. The discussion of HCN blockade also identifies off-target activity and safety concerns for other blockers. Our copy does not establish that many isoform-preferring tools have incomplete pharmacokinetic or off-target profiling, or that this results in narrow therapeutic windows and variable central effects. (LLM, conf=0.83)

    Experimental — accuracy not yet measured
  • In prefrontal cortex, HCN1-driven Ih stabilizes intrinsic persistent firing and supports working memory by maintaining depolarized up-states and filtering distractors within resonant frequency bands.

    “In prefrontal cortex, hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1)-driven Ih stabilizes intrinsic persistent firing and supports working memory by maintaining depolarized up-states and filtering distractors within resonant frequency bands [275,277,281].”

    From Synaptic Plasticity—Intrinsic Excitability and Antidepressant Discovery (2026) · cites this paper as [277]

    The section on HCN distribution and function (page unavailable) places HCN1 in prefrontal working-memory circuits and describes HCN current as contributing to neuronal resonance. It does not say that HCN1-driven Ih maintains depolarized up-states or filters distractors to stabilize persistent firing. Instead, it reports that inhibiting cAMP-HCN signaling strengthens recurring prefrontal circuit activity and improves performance, whereas enhanced activity disconnects the network and impairs working memory. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • Developmental increases of Ih in pyramidal neurons, along with cell-type-specific regulation by synaptic plasticity and FMRP, refine this gain control and may delineate windows of vulnerability to cognitive dysfunction.

    “Developmental increases of Ih in pyramidal neurons, along with cell-type specific regulation by synaptic plasticity and fragile X mental retardation protein (FMRP), refine this gain control and may delineate windows of vulnerability to cognitive dysfunction [277,278,281].”

    From Synaptic Plasticity—Intrinsic Excitability and Antidepressant Discovery (2026) · cites this paper as [277]

    The “HCN during Organogenesis” section reports a developmental increase in HCN1 expression in rat CA1 pyramidal neurons, while “Synaptic Excitability and Plasticity” describes HCN current shaping synaptic responses and plasticity. Our copy does not establish FMRP regulation of Ih or identify developmental windows of vulnerability to cognitive dysfunction; searches for “FMRP” and “fragile X” found no relevant passage. Page numbers were not available in the indexed passages. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • At the network level, HCN4 sustains thalamocortical rhythms that scaffold cortical timing.

    “At the network level, hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4) sustains thalamocortical rhythms that scaffold cortical timing, linking molecular gating to mesoscale oscillations [272,277,279].”

    From Synaptic Plasticity—Intrinsic Excitability and Antidepressant Discovery (2026) · cites this paper as [277]

    The “Rhythmogenesis” passage in section B says HCN channels help set the pace of membrane oscillations and influence thalamocortical firing. But it attributes thalamocortical HCN current mainly to HCN2, not HCN4, and does not establish that HCN4 sustains thalamocortical rhythms or scaffolds cortical timing. Page numbers were not available in our copy. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

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Authors
Sartiani, L., Mannaioni, G., Masi, A., Novella Romanelli, M., & Cerbai, E.
Affiliations
University of Florence (IT)
Venue
Pharmacological Reviews
Publisher
Elsevier BV
Published
2017-10
Volume
69
Issue
4
Pages
354-395
ISSN
0031-6997 (ISSN-L)
OpenAlex
W2753738702
Cited by
143
References
497
Citations by year
2026: 9 · 2025: 17 · 2024: 21 · 2023: 12 · 2022: 19 · 2021: 17 · 2020: 21 · 2019: 16 · 2018: 11
FWCI
1.23
Type
journal article
Language
en
Open access
Locations
  • Pharmacological Reviews (publishedVersion)
  • PubMed (publishedVersion)
  • Florence Research (University of Florence) (submittedVersion)
Funders
Ente Cassa di Risparmio di Firenze
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Ion channel regulation and function
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Cardiac electrophysiology and arrhythmias
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Ion Transport and Channel Regulation
Keywords
HCN channels, channel biophysics, channel development, cardiac pacemaking, synaptic transmission, heart rate, therapeutic target, ivabradine, channelopathies
MeSH terms
Animals, Biophysics, Humans, Ligands, Nucleotides, Cyclic, Structure-Activity Relationship, Molecular Targeted Therapy, Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels

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