GO:0086043 bundle of His cell action potential: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0086043 describes the action potential that occurs specifically in bundle of His cells, the specialized cardiac conduction cells that relay electrical excitation from the AV node to the ventricles.
• The bundle of His action potential depends on a unique complement of ion channels, including fast Na+ channels, L-type Ca2+ channels, and gap-junction proteins that differ from working myocardium.
• Disruption of bundle of His conduction causes reentrant ventricular arrhythmias, heart block, and conduction disturbances after cardiac procedures.
• The His-Purkinje system is a recognized source of ventricular arrhythmias, and bundle of His cells are key targets in catheter ablation and conduction-system pacing research.
• Aging and myocardial infarction alter conduction-system structure and function, making bundle of His cell electrophysiology relevant to age-related and ischemic conduction disease.
• CRISPR-based knockout, knock-in, and point-mutation models in cardiomyocyte and conduction-cell systems enable causal testing of genes underlying bundle of His action potential.
Description
The bundle of His is a specialized component of the cardiac conduction system that transmits electrical impulses from the atrioventricular node to the ventricular Purkinje network. The action potential generated by bundle of His cells, annotated as GO:0086043, is the electrical signal that propagates through these cells and ensures coordinated ventricular activation. Unlike working cardiomyocytes, bundle of His cells exhibit distinct action potential morphology and ion-channel expression that support rapid, reliable conduction. Understanding this process is essential because conduction failure or abnormal automaticity in the His-Purkinje system can produce life-threatening arrhythmias. Research on bundle of His cell action potential spans cardiac electrophysiology, developmental biology, and translational arrhythmia management. The His-Purkinje system has been implicated as a source of ventricular arrhythmias, and conduction disturbances are recognized complications of structural heart interventions. In addition, regeneration of the cardiac conduction system after myocardial infarction has emerged as a strategy to prevent arrhythmias, highlighting the therapeutic relevance of bundle of His cell biology. This article synthesizes authoritative Gene Ontology annotation for GO:0086043 with published literature to describe the mechanisms, key genes, disease associations, and experimental models relevant to bundle of His cell action potential. It is intended for researchers designing CRISPR-based studies of conduction-system genes and for clinicians seeking a mechanistic overview of His bundle electrophysiology.
bundle of His cell action potential At A Glance
| GO ID | GO:0086043 |
|---|---|
| GO term | bundle of His cell action potential |
| Ontology | biological_process |
| Synonym | bundle of His cardiac muscle cell action potential |
| Major function | Generation and propagation of the electrical action potential in bundle of His conduction cells, enabling atrioventricular impulse transmission |
| Cell type | Specialized cardiac conduction cells of the His bundle |
| Related anatomy | His-Purkinje system, linking the AV node to ventricular myocardium |
| Disease relevance | Reentrant arrhythmias, conduction block, and post-procedural conduction disturbances |
| Research relevance | Target for conduction-system regeneration, ablation safety, and CRISPR-based electrophysiology studies |
What Is GO:0086043?
GO:0086043 (bundle of His cell action potential) is defined in the Gene Ontology as an action potential that occurs in a bundle of His cell. In other words, it is the membrane voltage transient generated by specialized conduction cells of the His bundle, encompassing the rapid depolarization, plateau, and repolarization phases that together propagate electrical excitation toward the ventricles. This term is a biological process and is synonymous with bundle of His cardiac muscle cell action potential.
Why Is bundle of His cell action potential Important in Cell Biology?
The bundle of His cell action potential is important because it represents the final common pathway for electrical activation of the ventricles; failure or slowing of this signal directly translates into conduction block, bradycardia, or reentrant ventricular arrhythmias. Because the His-Purkinje system can itself be a source of arrhythmogenic activity, understanding the ionic and structural basis of bundle of His action potentials informs both diagnostic electrocardiography and therapeutic ablation strategies. Moreover, conduction-system regeneration after myocardial infarction has been proposed as an antiarrhythmic strategy, making bundle of His cell biology a translational research priority.
• Bundle of His cells provide the only normal electrical bridge between atria and ventricles, so their action potential is essential for coordinated ventricular contraction.
• Abnormal bundle of His conduction underlies reentrant arrhythmias and heart block, which are major causes of morbidity.
• The His-Purkinje system is a recognized source of ventricular arrhythmias, including idiopathic and scar-related forms.
• Pulsed electric field ablation can affect His bundle conduction, making mechanistic understanding critical for procedural safety.
• Transcatheter tricuspid valve replacement can produce new-onset conductance disturbances involving the His bundle.
• Aging alters cardiac conduction, and age-related changes in the His bundle contribute to conduction disease.
• Myocardial infarction can damage the conduction system, and regeneration of conduction tissue may prevent arrhythmias.
• Bundle of His action potential research supports development of conduction-system pacing and biological pacemakers.
• Ion-channel and gap-junction genes expressed in His bundle cells are candidate targets for CRISPR-based functional studies.
• Electrocardiographic interpretation of conduction intervals depends on understanding His bundle electrophysiology.
What Happens During bundle of His cell action potential?
Phase 0: Rapid Depolarization
In simple terms: The bundle of His cell suddenly becomes positive inside as sodium ions rush in.
The bundle of His cell action potential begins with a rapid upstroke (phase 0) driven by activation of voltage-gated fast sodium channels, which produce a large inward sodium current. This rapid depolarization is characteristic of specialized conduction cells and ensures high conduction velocity through the His bundle. The threshold for excitation in these cells is influenced by their resting membrane potential and the availability of sodium channels.
Phase 1 and 2: Early Repolarization and Plateau
In simple terms: The cell briefly dips and then holds a plateau as calcium ions enter.
After the initial spike, a transient outward current causes slight early repolarization (phase 1), followed by a plateau phase (phase 2) maintained by inward L-type calcium current balanced against outward potassium currents. In bundle of His cells, the plateau is relatively abbreviated compared with ventricular myocytes, contributing to the shorter action potential duration typical of conduction tissue. This phase is critical for determining refractoriness and preventing reentrant excitation.
Phase 3: Repolarization
In simple terms: Potassium ions leave the cell, bringing the voltage back down.
Repolarization (phase 3) is mediated by activation of multiple potassium currents, including delayed rectifier and inward rectifier currents, which restore the resting membrane potential. The balance of these currents determines action potential duration and the effective refractory period of bundle of His cells. Abnormalities in repolarization can create substrates for reentrant arrhythmias involving the His-Purkinje system.
Phase 4: Resting Potential and Automaticity
In simple terms: Between beats, the cell maintains a stable negative voltage but can occasionally fire on its own.
In the resting state (phase 4), bundle of His cells maintain a negative membrane potential primarily through inward rectifier potassium channels. Some conduction cells exhibit spontaneous diastolic depolarization, contributing to automaticity that can become arrhythmogenic under pathological conditions. This automaticity is normally suppressed by overdrive pacing from the sinus node but can emerge in disease states.
Propagation to the Ventricular Purkinje Network
In simple terms: The electrical signal travels from the His bundle into the Purkinje fibers and then the ventricles.
The action potential generated in bundle of His cells propagates rapidly through gap junctions to the Purkinje network and ventricular myocardium. This coordinated transmission ensures synchronous ventricular activation and efficient pumping. Disruption of this propagation, whether by fibrosis, ischemia, or ablation, can cause conduction block or reentrant arrhythmias.
Key Genes Involved in GO:0086043 bundle of His cell action potential
The following genes encode ion channels, gap-junction proteins, and regulatory factors that contribute to the bundle of His cell action potential and its propagation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SCN5A | Voltage-gated sodium channel alpha subunit mediating phase 0 depolarization | Mutations cause Brugada syndrome and conduction disease; target for CRISPR knock-in studies |
| CACNA1C | L-type calcium channel alpha subunit contributing to plateau phase | Important for action potential duration and calcium-dependent conduction; knockout models available |
| KCNQ1 | Delayed rectifier potassium channel alpha subunit | Repolarization reserve; mutations linked to long QT syndrome |
| KCNH2 | Rapid delayed rectifier potassium channel alpha subunit | Repolarization and arrhythmia susceptibility; target for point-mutation models |
| KCNJ2 | Inward rectifier potassium channel setting resting potential | Determines phase 4 stability; knockout alters conduction |
| GJA1 | Connexin 43 gap-junction protein | Mediates cell-to-cell coupling in conduction tissue; knockout slows conduction |
| GJA5 | Connexin 40 gap-junction protein | Highly expressed in His-Purkinje system; critical for fast conduction |
| HCN4 | Hyperpolarization-activated cyclic nucleotide-gated channel | Contributes to automaticity in conduction cells; knockout affects rhythm |
| TBX3 | Transcription factor regulating conduction system development | Represses working myocardial genes in His-Purkinje cells; knockout models |
| TBX5 | Transcription factor essential for conduction system formation | Mutations cause conduction defects; target for knock-in |
| NKX2-5 | Homeobox transcription factor in cardiac conduction | Regulates ion-channel gene expression; knockout causes conduction abnormalities |
| IRX3 | Transcription factor patterning the conduction system | Involved in His-Purkinje specification; overexpression models |
| NPPA | Natruretic peptide precursor A | Marker of working myocardium; repressed in conduction cells |
| MYH6 | Alpha myosin heavy chain | Contractile gene repressed in conduction cells; useful for lineage tracing |
| RYR2 | Ryanodine receptor 2 | Calcium release channel influencing action potential and conduction |
| ATP2A2 | SERCA2 calcium pump | Regulates calcium handling and repolarization |
| SCN1B | Sodium channel beta subunit | Modulates sodium current; mutations affect conduction |
| ANK2 | Ankyrin-2 cytoskeletal adaptor | Links ion channels to membrane; mutations cause arrhythmia |
How Is bundle of His cell action potential Regulated?
The bundle of His cell action potential is regulated by autonomic tone, transcriptional programs, and post-translational modifications of ion channels. Sympathetic stimulation increases heart rate and conduction velocity by enhancing sodium and calcium currents, while parasympathetic activity slows conduction. Transcription factors such as TBX3, TBX5, and NKX2-5 establish the conduction-cell phenotype by repressing working myocardial genes and activating ion-channel genes. In disease states, fibrosis and ischemia alter gap-junction distribution and ion-channel function, modifying action potential propagation. Regeneration of the conduction system after myocardial infarction involves reactivation of developmental programs that may restore bundle of His function.
bundle of His cell action potential and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SCN5A | Brugada syndrome, conduction disease | Knock-in mouse or hiPSC-CM point mutation |
| GJA5 | Atrial fibrillation, conduction slowing | Knockout mouse or CRISPR knockout in conduction cells |
| TBX5 | Holt-Oram syndrome with conduction defects | Knock-in or knockout in cardiomyocyte differentiation |
| NKX2-5 | Congenital heart block and conduction abnormalities | Knockout mouse and hiPSC-derived conduction cells |
| HCN4 | Sinus node dysfunction and conduction disease | Overexpression or knockout in conduction cell models |
Reentrant Arrhythmias and Conduction Block
Abnormal bundle of His cell action potentials can initiate or sustain reentrant arrhythmias, including ventricular tachycardia and fibrillation. Slowed conduction and unidirectional block in the His-Purkinje system create the substrate for reentry, which is a leading mechanism of sudden cardiac death. Conduction block at the His bundle level produces atrioventricular block and bradycardia, often requiring pacing.
Post-Procedural Conduction Disturbances
Interventions near the His bundle, such as pulsed electric field ablation and transcatheter tricuspid valve replacement, can impair bundle of His conduction and cause new-onset conduction disturbances. Preclinical studies show that pulsed electric field ablation affects His bundle conduction in a dose-dependent manner, informing safety margins. Clinical reports document conductance disturbances after tricuspid valve replacement, highlighting the vulnerability of the His bundle to mechanical and procedural injury.
Aging and Ischemic Heart Disease
Aging is associated with structural and functional changes in the cardiac conduction system, including fibrosis and altered ion-channel expression, which slow bundle of His conduction. Myocardial infarction can damage the His-Purkinje network, leading to conduction block and arrhythmias. Regeneration of the conduction system after infarction has been proposed as a therapeutic strategy to prevent arrhythmias.
From bundle of His cell action potential-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of SCN5A alter bundle of His action potential upstroke? | CRISPR knockout in hiPSC-derived conduction cells or mouse |
| Does a specific point mutation in KCNH2 prolong repolarization? | Point-mutation knock-in in cardiomyocytes |
| Can TBX3 overexpression induce conduction-cell phenotype? | Overexpression in hiPSC-derived cardiomyocytes |
| Does GJA5 knockout slow His bundle conduction? | Knockout mouse with electrophysiology |
| Can conduction-system regeneration prevent post-infarction arrhythmias? | Lineage tracing and knockout in mouse infarction models |
| Does pulsed electric field ablation affect His bundle conduction? | Preclinical canine model |
How to Study the bundle of His cell action potential Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Patch-clamp | Action potential and ionic currents | Characterize bundle of His cell electrophysiology |
| Optical mapping | Conduction velocity and activation patterns | Detect reentry and conduction block |
| RNA-seq | Gene expression profiles | Identify ion-channel and gap-junction genes |
| Single-cell RNA-seq | Cell-type heterogeneity | Resolve conduction cell subtypes |
| Immunohistochemistry | Protein localization | Assess connexin distribution |
| CRISPR screening | Gene function at scale | Discover regulators of conduction |
| hiPSC differentiation | Conduction cell phenotype | Model human bundle of His cells |
| In vivo electrophysiology | His bundle conduction intervals | Assess conduction in animal models |
Patch-Clamp Electrophysiology
Patch-clamp recordings directly measure action potentials and ionic currents in isolated bundle of His cells or hiPSC-derived conduction cells. This method defines the phases of the action potential and identifies contributions of specific ion channels. It is the gold standard for validating CRISPR-induced changes in excitability.
Optical Mapping and Voltage Imaging
Optical mapping with voltage-sensitive dyes visualizes conduction velocity and activation patterns in multicellular preparations, including the His-Purkinje system. This approach can detect reentrant circuits and conduction block in genetically modified models. It complements patch-clamp by providing spatial information.
Transcriptomics and Single-Cell RNA Sequencing
RNA sequencing of conduction tissue or hiPSC-derived cells identifies ion-channel and gap-junction gene expression profiles characteristic of bundle of His cells. Single-cell approaches resolve heterogeneity among conduction cells and reveal regulatory networks. These data guide selection of CRISPR targets.
Immunohistochemistry and Connexin Imaging
Immunostaining for connexins and ion channels reveals the distribution of proteins that underlie bundle of His action potential propagation. Alterations in gap-junction localization are associated with conduction slowing in disease. Imaging can be combined with electrophysiology for mechanistic studies.
How CRISPR Can Be Used to Study GO:0086043 bundle of His cell action potential
Knockout
CRISPR knockout of ion-channel or gap-junction genes in hiPSC-derived conduction cells or mouse models can reveal their requirement for bundle of His cell action potential. For example, knockout of GJA5 or SCN5A is expected to slow conduction or reduce excitability. These models provide causal evidence linking genes to electrophysiological phenotypes.
Point Mutation
Point mutations identified in patients with conduction disease can be introduced into cell models to test their effect on action potential morphology. For example, KCNH2 or SCN5A mutations can be modeled to assess repolarization or depolarization defects. Such studies help classify variants of uncertain significance.
Knock-in
Knock-in of reporter genes or epitope tags into conduction-system loci enables lineage tracing and protein localization in bundle of His cells. Tagged knock-in of ion channels can facilitate biochemical studies of channel complexes. This approach is valuable for understanding developmental origins of conduction cells.
Overexpression
Overexpression of transcription factors such as TBX3 or ion channels can reprogram cardiomyocytes toward a conduction-like phenotype. Overexpression models can test sufficiency of a gene to induce bundle of His action potential properties. They are also used to study gain-of-function mutations.
How EDITGENE Supports bundle of His cell action potential Research
Researchers studying bundle of His cell action potential-related genes often need to determine whether a candidate gene is causally involved in conduction phenotypes. EDITGENE provides CRISPR-based cell model services that enable precise genetic manipulation in cardiomyocyte and conduction-cell systems, supporting mechanistic and translational studies of GO:0086043.
Contact EDITGENE today to design your custom CRISPR model for bundle of His cell action potential research.
Frequently Asked Questions About bundle of His cell action potential
What is GO:0086043 bundle of His cell action potential?
GO:0086043 is a Gene Ontology biological process term defined as an action potential that occurs in a bundle of His cell, the specialized cardiac conduction cell that relays electrical signals from the AV node to the ventricles.
What genes are involved in bundle of His cell action potential?
Key genes include SCN5A, CACNA1C, KCNQ1, KCNH2, KCNJ2, GJA1, GJA5, HCN4, and transcription factors such as TBX3, TBX5, and NKX2-5.
Why is the bundle of His action potential important?
It ensures coordinated ventricular activation; disruption causes conduction block, bradycardia, and reentrant arrhythmias.
What diseases are linked to bundle of His cell action potential dysfunction?
Reentrant arrhythmias, atrioventricular block, Brugada syndrome, long QT syndrome, and post-procedural conduction disturbances.
How do researchers study bundle of His cell action potential?
Patch-clamp electrophysiology, optical mapping, RNA sequencing, immunohistochemistry, and in vivo electrophysiology in animal models.
Can CRISPR be used to study bundle of His cell action potential genes?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models in hiPSC-derived cardiomyocytes or mouse models enable causal testing of conduction genes.
What is the role of gap junctions in bundle of His conduction?
Gap junctions formed by connexins such as GJA1 and GJA5 mediate cell-to-cell electrical coupling, enabling rapid propagation of the action potential through the His bundle.
How does aging affect bundle of His cell action potential?
Aging is associated with fibrosis and altered ion-channel expression in the conduction system, which can slow conduction and predispose to arrhythmias.
What happens to His bundle conduction after cardiac procedures?
Pulsed electric field ablation and transcatheter tricuspid valve replacement can impair His bundle conduction, leading to new-onset conduction disturbances.
Can conduction-system regeneration prevent arrhythmias?
Preclinical studies suggest that regenerating the cardiac conduction system after myocardial infarction can prevent arrhythmias, highlighting therapeutic potential.
Conclusion
GO:0086043 bundle of His cell action potential represents a specialized electrical process essential for normal cardiac rhythm and ventricular activation. Its dysfunction is implicated in reentrant arrhythmias, conduction block, and post-procedural complications, making it a critical area of cardiovascular research. Advances in CRISPR-based models and electrophysiological methods now allow precise interrogation of the genes and mechanisms underlying bundle of His cell action potential, supporting the development of targeted therapies and improved clinical outcomes.
References
- 1. Goyal A et al.. 2026. Reentry Arrhythmia.. PMID: 30725774
- 2. Sayers JR et al.. 2025. Cardiac conduction system regeneration prevents arrhythmias after myocardial infarction.. Nat Cardiovasc Res 4(2):163-179 PMID: 39753976
- 3. McMahon K et al.. 2026. ECG T Wave.. PMID: 30855852
- 4. Boyden PA et al.. 2010. Cardiac Purkinje cells.. Heart Rhythm 7(1):127-35 PMID: 19939742
- 5. Zhai Z et al.. 2024. Impact of Pulsed Electric Field Ablation on His Bundle Conduction: A Preclinical Canine Study.. Med Sci Monit 30:e945007 PMID: 39078809
- 6. Le Ruz R et al.. 2025. New-Onset Conductance Disturbances After Transcatheter Tricuspid Valve Replacement: A Mechanistic Assessment.. JACC Cardiovasc Interv 18(21):2569-2579 PMID: 41085507
- 7. Haissaguerre M et al.. 2016. Ventricular arrhythmias and the His-Purkinje system.. Nat Rev Cardiol 13(3):155-66 PMID: 26727298
- 8. Klausner SC et al.. 1985. The aging heart.. Clin Geriatr Med 1(1):119-41 PMID: 3913496
