GO:0086002 cardiac muscle cell action potential involved in contraction: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0086002 describes the action potential that occurs in cardiac muscle cells and is involved in their contraction.
• The cardiac action potential is initiated by a rapid depolarization driven by sodium current, followed by a plateau phase maintained by calcium influx.
• Calcium entering through L-type calcium channels triggers calcium release from the sarcoplasmic reticulum via ryanodine receptors, a process known as excitation-contraction coupling.
• The action potential duration and shape are critical for proper contraction and are regulated by potassium currents and sodium-calcium exchange.
• Dysregulation of the cardiac action potential is linked to arrhythmias, heart failure, and diabetic cardiomyopathy.
• Key genes involved include SCN5A, CACNA1C, RYR2, ATP2A2, and KCNQ1, which are essential for the generation and propagation of the cardiac action potential.
Description
The cardiac muscle cell action potential involved in contraction (GO:0086002) is a fundamental biological process that underlies the rhythmic beating of the heart. This action potential is a transient change in membrane potential that triggers the contraction of cardiac muscle cells, enabling the heart to pump blood effectively. Understanding this process is crucial for researchers studying cardiac physiology, arrhythmias, and heart failure, as disruptions in the action potential can lead to life-threatening conditions. The action potential in cardiac muscle cells is distinct from that in skeletal muscle or neurons, featuring a prolonged plateau phase that allows for sustained contraction and prevents tetany. This process is orchestrated by a complex interplay of ion channels, transporters, and intracellular signaling pathways.
cardiac muscle cell action potential involved in contraction At A Glance
| GO ID | GO:0086002 |
|---|---|
| GO term | cardiac muscle cell action potential involved in contraction |
| Ontology | biological_process |
| Synonym | None |
| Major function | Generation of electrical impulses that trigger cardiac muscle contraction |
| Related cellular components | Sarcolemma, T-tubules, sarcoplasmic reticulum, gap junctions |
| Related molecular functions | Ion channel activity, calcium release, ion exchange |
| Key ions involved | Sodium (Na+), Calcium (Ca2+), Potassium (K+) |
| Physiological outcome | Coordinated contraction of the heart |
What Is GO:0086002?
GO:0086002 is defined as an action potential that occurs in a cardiac muscle cell and is involved in its contraction. In simpler terms, it is the electrical signal that tells heart muscle cells to contract, ensuring the heart beats in a coordinated manner.
Why Is cardiac muscle cell action potential involved in contraction Important in Cell Biology?
The cardiac muscle cell action potential is essential for normal heart function, as it ensures that contraction occurs in a synchronized manner. Abnormalities in this process can lead to arrhythmias, heart failure, and other cardiovascular diseases. Research into this process is vital for developing therapeutic strategies targeting ion channels and calcium handling proteins.
• It initiates and coordinates cardiac muscle contraction, which is necessary for blood circulation.
• It integrates electrical signals with mechanical contraction through excitation-contraction coupling.
• Dysfunction of the action potential can cause arrhythmias such as long QT syndrome and atrial fibrillation.
• It is a target for antiarrhythmic drugs that modulate ion channels.
• It is affected in heart failure and diabetic cardiomyopathy, contributing to contractile dysfunction.
• It is a key focus in cardiac regenerative medicine and stem cell-derived cardiomyocyte research.
• It is regulated by the autonomic nervous system and circulating electrolytes.
• It is studied using electrophysiological techniques like patch clamp and voltage-sensitive dyes.
• It is influenced by genetic variants in ion channel genes, which can predispose to sudden cardiac death.
• It is a model system for understanding excitable cell biology and calcium signaling.
What Happens During cardiac muscle cell action potential involved in contraction?
Phase 0: Rapid Depolarization
In simple terms: The cell rapidly becomes positive inside due to sodium rushing in.
The action potential begins when the membrane potential reaches threshold, opening voltage-gated sodium channels (SCN5A). This causes a rapid influx of sodium ions, leading to depolarization of the cell membrane. The sodium current is responsible for the upstroke of the action potential and is essential for the initiation of contraction.
Phase 1: Early Repolarization
In simple terms: A brief partial return toward negative inside as sodium channels close and potassium starts to leave.
Following the peak, sodium channels inactivate, and transient outward potassium currents (Ito) cause a small repolarization phase. This phase is more prominent in atrial and ventricular myocytes and contributes to the shape of the action potential.
Phase 2: Plateau Phase
In simple terms: A sustained period where calcium entering the cell balances potassium leaving, keeping the cell depolarized.
The plateau phase is maintained by a balance between inward calcium current through L-type calcium channels (CACNA1C) and outward potassium currents. Calcium influx during this phase triggers calcium release from the sarcoplasmic reticulum, which is crucial for contraction. This prolonged depolarization prevents premature re-excitation and allows for sustained contraction.
Phase 3: Repolarization
In simple terms: The cell returns to its negative resting state as potassium leaves and calcium channels close.
Repolarization occurs as calcium channels inactivate and potassium channels (e.g., KCNQ1, KCNH2) open, allowing potassium efflux. The sodium-calcium exchanger (NCX) also contributes by exchanging three sodium ions for one calcium ion, helping to restore resting membrane potential.
Phase 4: Resting Potential
In simple terms: The cell is at rest, ready for the next signal.
During diastole, the membrane potential is maintained near -90 mV by the inward rectifier potassium current (IK1). The sodium-potassium ATPase and sodium-calcium exchanger help restore ionic gradients.
Excitation-Contraction Coupling
In simple terms: The electrical signal is converted into a mechanical contraction via calcium.
Calcium entering through L-type calcium channels triggers calcium-induced calcium release from the sarcoplasmic reticulum via ryanodine receptors (RYR2). The resulting increase in cytosolic calcium binds to troponin C, leading to cross-bridge cycling and contraction. Relaxation occurs when calcium is reuptaken into the sarcoplasmic reticulum by SERCA2a (ATP2A2) and extruded by NCX.
Key Genes Involved in GO:0086002 cardiac muscle cell action potential involved in contraction
The following genes encode key ion channels, transporters, and calcium-handling proteins that are essential for the cardiac muscle cell action potential and contraction.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SCN5A | Voltage-gated sodium channel alpha subunit | Mutations cause Brugada syndrome and long QT syndrome |
| CACNA1C | L-type calcium channel alpha-1C subunit | Mutations linked to Timothy syndrome and Brugada syndrome |
| RYR2 | Ryanodine receptor 2, calcium release channel | Mutations cause catecholaminergic polymorphic ventricular tachycardia |
| ATP2A2 | SERCA2a, calcium pump of sarcoplasmic reticulum | Defects contribute to heart failure and diastolic dysfunction |
| KCNQ1 | Voltage-gated potassium channel Kv7.1 | Mutations cause long QT syndrome type 1 |
| KCNH2 | Voltage-gated potassium channel Kv11.1 (hERG) | Mutations cause long QT syndrome type 2 |
| SCN1B | Sodium channel beta-1 subunit | Modulates sodium current; mutations linked to Brugada syndrome |
| CALM1 | Calmodulin 1 | Regulates calcium channels and ryanodine receptors; mutations cause CPVT |
| CALM2 | Calmodulin 2 | Similar to CALM1; mutations associated with long QT syndrome |
| CALM3 | Calmodulin 3 | Regulates calcium signaling; mutations linked to cardiac arrhythmias |
| CASQ2 | Calsequestrin 2 | Calcium buffer in sarcoplasmic reticulum; mutations cause CPVT |
| TRDN | Triadin | Anchors calsequestrin to ryanodine receptor; mutations cause CPVT |
| JPH2 | Junctophilin 2 | Maintains junctional membrane structure; mutations linked to cardiomyopathy |
| PLN | Phospholamban | Regulates SERCA2a activity; mutations cause cardiomyopathy |
| NPPA | Atrial natriuretic peptide | Marker of cardiac stress; used in cardiomyocyte differentiation |
| MYH7 | Beta-myosin heavy chain | Contractile protein; mutations cause hypertrophic cardiomyopathy |
| TNNT2 | Cardiac troponin T | Regulates contraction; mutations cause cardiomyopathy |
| GJA1 | Connexin 43 | Gap junction protein for electrical coupling |
How Is cardiac muscle cell action potential involved in contraction Regulated?
The cardiac action potential is regulated by multiple mechanisms, including autonomic nervous system input, electrolyte balance, and intracellular signaling pathways. Beta-adrenergic stimulation increases heart rate and contractility by modulating ion channel activity and calcium handling. Electrolyte imbalances, such as hypokalemia or hypercalcemia, can alter action potential duration and excitability. Additionally, calcium-calmodulin-dependent protein kinase II (CaMKII) and protein kinase A (PKA) phosphorylate key calcium-handling proteins, thereby modulating excitation-contraction coupling.
cardiac muscle cell action potential involved in contraction and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SCN5A | Brugada syndrome, long QT syndrome | Knockout or point mutation in hiPSC-derived cardiomyocytes |
| KCNQ1 | Long QT syndrome type 1 | Knock-in of patient-specific mutation in HEK293 or cardiomyocytes |
| RYR2 | Catecholaminergic polymorphic ventricular tachycardia | Knock-in mouse model or hiPSC-derived cardiomyocytes |
| ATP2A2 | Heart failure, diastolic dysfunction | Overexpression or knockout in cardiomyocytes |
| CALM1 | CPVT, long QT syndrome | Point mutation knock-in in hiPSC-derived cardiomyocytes |
Arrhythmias and Channelopathies
Mutations in genes encoding ion channels (e.g., SCN5A, KCNQ1, KCNH2) can cause inherited arrhythmia syndromes such as long QT syndrome and Brugada syndrome. These conditions are characterized by abnormal action potential duration and increased risk of sudden cardiac death.
Heart Failure and Diabetic Cardiomyopathy
In heart failure, alterations in calcium handling and ion channel expression lead to prolonged action potentials and impaired contraction. Diabetic cardiomyopathy is associated with diastolic dysfunction and arrhythmia, partly due to altered calcium signaling and action potential remodeling.
Atrial Fibrillation
Atrial fibrillation involves electrical remodeling that shortens the atrial action potential and promotes reentry. Changes in ion channel expression, particularly calcium and potassium channels, contribute to the initiation and maintenance of this arrhythmia.
From cardiac muscle cell action potential involved in contraction-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of SCN5A affect action potential upstroke? | SCN5A knockout in hiPSC-derived cardiomyocytes |
| Does a specific KCNQ1 mutation cause long QT? | KCNQ1 point mutation knock-in in hiPSC-derived cardiomyocytes |
| Can overexpression of SERCA2a rescue contractile dysfunction? | ATP2A2 overexpression in heart failure model |
| How does RYR2 mutation affect calcium release? | RYR2 knock-in mouse or hiPSC-derived cardiomyocytes |
| What is the role of CALM1 in arrhythmogenesis? | CALM1 knockout or point mutation in cardiomyocytes |
| Does GJA1 knockout disrupt electrical coupling? | GJA1 knockout in cardiac tissue or hiPSC-derived cardiomyocytes |
How to Study the cardiac muscle cell action potential involved in contraction Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Patch clamp | Action potentials and ion currents | Characterization of ion channel function |
| Calcium imaging | Intracellular calcium transients | Assessment of excitation-contraction coupling |
| Optical mapping | Spatiotemporal action potential propagation | Arrhythmia studies in tissue |
| CRISPR-Cas9 knockout | Loss-of-function effects | Determining gene necessity |
| CRISPR-Cas9 knock-in | Specific mutation effects | Modeling inherited channelopathies |
| RNA sequencing | Gene expression profiles | Identifying transcriptomic changes |
| Proteomics | Protein expression and modifications | Quantifying ion channel abundance |
Patch Clamp Electrophysiology
Patch clamp is the gold standard for measuring action potentials and ion currents in cardiomyocytes. It allows detailed characterization of ion channel function and the effects of genetic mutations.
Calcium Imaging
Calcium imaging using fluorescent dyes or genetically encoded indicators visualizes intracellular calcium transients, providing insights into excitation-contraction coupling and calcium handling abnormalities.
Optical Mapping
Optical mapping with voltage-sensitive dyes enables simultaneous recording of action potentials from multiple sites in cardiac tissue, useful for studying arrhythmia mechanisms.
CRISPR-Cas9 Genome Editing
CRISPR-Cas9 allows precise modification of genes encoding ion channels and calcium-handling proteins in cardiomyocytes, enabling causal studies of their roles in the action potential.
How CRISPR Can Be Used to Study GO:0086002 cardiac muscle cell action potential involved in contraction
Knockout
CRISPR knockout of genes such as SCN5A or RYR2 in cardiomyocytes can reveal their essential roles in the action potential and contraction. For example, SCN5A knockout abolishes the rapid upstroke, while RYR2 knockout impairs calcium release.
Point Mutation
Introducing patient-specific point mutations (e.g., in KCNQ1 or SCN5A) using CRISPR allows modeling of channelopathies and testing of drug responses. This approach provides insights into how single amino acid changes alter channel function.
Knock-in
Knock-in of reporter genes or tags (e.g., fluorescently tagged CACNA1C) enables real-time visualization of channel localization and dynamics in live cardiomyocytes. This helps study trafficking and membrane expression.
Overexpression
Overexpression of genes like ATP2A2 (SERCA2a) or PLN can rescue or exacerbate contractile dysfunction in disease models. CRISPR activation (CRISPRa) can be used to upregulate endogenous genes.
How EDITGENE Supports cardiac muscle cell action potential involved in contraction Research
Researchers studying cardiac muscle cell action potential involved in contraction-related genes often need to determine whether a candidate gene is causally involved in the process. EDITGENE provides comprehensive CRISPR-based services to create precise cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for cardiac muscle cell action potential involved in contraction research.
Frequently Asked Questions About cardiac muscle cell action potential involved in contraction
What is GO:0086002?
GO:0086002 is a Gene Ontology term for the cardiac muscle cell action potential involved in contraction, describing the electrical signal that triggers heart muscle contraction.
What genes are involved in cardiac muscle cell action potential involved in contraction?
Key genes include SCN5A, CACNA1C, RYR2, ATP2A2, KCNQ1, KCNH2, and others encoding ion channels and calcium-handling proteins.
How is the cardiac action potential regulated?
It is regulated by autonomic nervous system input, electrolytes, and phosphorylation of ion channels and calcium-handling proteins.
What diseases are associated with abnormal cardiac action potentials?
Arrhythmias, long QT syndrome, Brugada syndrome, heart failure, and diabetic cardiomyopathy are associated with action potential abnormalities.
What methods are used to study the cardiac action potential?
Patch clamp, calcium imaging, optical mapping, and CRISPR genome editing are commonly used.
What is excitation-contraction coupling?
It is the process by which the electrical action potential triggers calcium release and muscle contraction.
How does calcium trigger contraction in cardiomyocytes?
Calcium binds to troponin C, moving tropomyosin and allowing actin-myosin cross-bridge cycling.
What is the role of sodium-calcium exchange in the action potential?
NCX helps restore resting calcium levels and contributes to repolarization by exchanging sodium and calcium.
Can CRISPR be used to model cardiac channelopathies?
Yes, CRISPR knockout or knock-in of specific mutations in hiPSC-derived cardiomyocytes can model channelopathies.
What are the phases of the cardiac action potential?
The phases are 0 (depolarization), 1 (early repolarization), 2 (plateau), 3 (repolarization), and 4 (resting potential).
Conclusion
The cardiac muscle cell action potential involved in contraction (GO:0086002) is a cornerstone of cardiac physiology, integrating electrical signaling with mechanical contraction. Understanding its molecular underpinnings and regulation is essential for developing therapies for arrhythmias and heart failure. Advanced CRISPR models and electrophysiological methods continue to unravel the complexities of this process, offering hope for precision medicine in cardiovascular disease.
References
- 1. Shrimanker I et al.. 2026. Electrolytes.. PMID: 31082167
- 2. Mira Hernandez J et al.. 2025. Differential sex-dependent susceptibility to diastolic dysfunction and arrhythmia in cardiomyocytes from obese diabetic heart failure with preserved ejection fraction model.. Cardiovasc Res 121(2):254-266 PMID: 38666446
- 3. Terrar DA. 2020. Calcium Signaling in the Heart.. Adv Exp Med Biol 1131:395-443 PMID: 31646519
- 4. Liu J et al.. 2016. The electrophysiological development of cardiomyocytes.. Adv Drug Deliv Rev 96:253-73 PMID: 26788696
- 5. Blatter LA et al.. 2021. Excitation-contraction coupling and calcium release in atrial muscle.. Pflugers Arch 473(3):317-329 PMID: 33398498
- 6. Demydenko K et al.. 2022. Inositol 1,4,5-trisphosphate receptors in cardiomyocyte physiology and disease.. Philos Trans R Soc Lond B Biol Sci 377(1864):20210319 PMID: 36189803
- 7. Arlock P et al.. 2023. Excitation and contraction of cardiac muscle and coronary arteries of brain-dead pigs.. FASEB Bioadv 5(2):71-84 PMID: 36816513
- 8. Blaustein MP et al.. 1999. Sodium/calcium exchange: its physiological implications.. Physiol Rev 79(3):763-854 PMID: 10390518
