membrane repolarization during bundle of His cell action potential
Definition
Target type: biologicalprocess
The process in which ions are transported across a membrane such that the bundle of His cardiac muscle cell membrane potential changes in the direction from the positive membrane potential at the peak of the action potential towards the negative resting potential. [GOC:BHF, GOC:dph, GOC:mtg_cardiac_conduct_nov11]
Membrane repolarization during the bundle of His cell action potential is a critical phase in the cardiac conduction system that ensures the rapid and coordinated propagation of electrical impulses throughout the heart. It follows the depolarization phase, where the cell membrane potential becomes more positive due to the influx of sodium ions.
During repolarization, the cell membrane potential returns to its resting state, a process driven primarily by the outward movement of potassium ions. This outward potassium current is facilitated by the opening of voltage-gated potassium channels, specifically the delayed rectifier potassium channels. These channels are activated when the membrane potential becomes sufficiently positive, allowing potassium ions to flow out of the cell down their electrochemical gradient.
The efflux of potassium ions counteracts the positive influx of sodium ions during depolarization, causing the membrane potential to become more negative. This repolarization phase is characterized by a rapid decline in the action potential, returning the cell to its polarized state.
The rate and duration of repolarization are crucial for maintaining the proper rhythm and timing of cardiac contraction. An abnormal repolarization process can lead to irregular heartbeats, including arrhythmias.
In summary, membrane repolarization during the bundle of His cell action potential is a vital process that ensures the rapid and coordinated propagation of electrical impulses in the heart. It is driven by the outward movement of potassium ions through voltage-gated potassium channels, returning the cell to its polarized state and setting the stage for the next cardiac cycle.'
"
Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Potassium voltage-gated channel subfamily A member 5 | A voltage-gated potassium channel subunit KCNA5 that is encoded in the genome of human. [] | Homo sapiens (human) |
Compounds (16)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| N-(2-aminoethyl)-5-chloro-1-naphthalenesulfonamide | naphthalenes; sulfonic acid derivative | ||
| 5-methoxypsoralen | 5-methoxypsoralen : A 5-methoxyfurocoumarin that is psoralen substituted by a methoxy group at position 5. 5-Methoxypsoralen: A linear furanocoumarin that has phototoxic and anti-inflammatory properties, with effects similar to METHOXSALEN. It is used in PUVA THERAPY for the treatment of PSORIASIS. | 5-methoxyfurocoumarin; organic heterotricyclic compound; psoralens | hepatoprotective agent; plant metabolite |
| flecainide | flecainide : A monocarboxylic acid amide obtained by formal condensation of the carboxy group of 2,5-bis(2,2,2-trifluoroethoxy)benzoic acid with the primary amino group of piperidin-2-ylmethylamine. An antiarrhythmic agent used (in the form of its acetate salt) to prevent and treat tachyarrhythmia (abnormal fast rhythm of the heart). Flecainide: A potent anti-arrhythmia agent, effective in a wide range of ventricular and atrial ARRHYTHMIAS and TACHYCARDIAS. | aromatic ether; monocarboxylic acid amide; organofluorine compound; piperidines | anti-arrhythmia drug |
| lidocaine | lidocaine : The monocarboxylic acid amide resulting from the formal condensation of N,N-diethylglycine with 2,6-dimethylaniline. Lidocaine: A local anesthetic and cardiac depressant used as an antiarrhythmia agent. Its actions are more intense and its effects more prolonged than those of PROCAINE but its duration of action is shorter than that of BUPIVACAINE or PRILOCAINE. | benzenes; monocarboxylic acid amide; tertiary amino compound | anti-arrhythmia drug; drug allergen; environmental contaminant; local anaesthetic; xenobiotic |
| nifedipine | Nifedipine: A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure. | C-nitro compound; dihydropyridine; methyl ester | calcium channel blocker; human metabolite; tocolytic agent; vasodilator agent |
| sertindole | sertindole : A phenylindole that is 1H-indole which is substituted on the nitrogen by a p-chlorophenyl group, at position 5 by chlorine, and at position 3 by a piperidin-4-yl group, which is itself substituted on the nitrogen by a 2-(2-oxoimidazolidin-1-yl)ethyl group. | heteroarylpiperidine; imidazolidinone; organochlorine compound; organofluorine compound; phenylindole | alpha-adrenergic antagonist; H1-receptor antagonist; second generation antipsychotic; serotonergic antagonist |
| 4'-methoxyflavone | 4'-methoxyflavone: from seeds of Psoralea corylifolia (Fabaceae); structure in first source | ether; flavonoids | |
| senicapoc | senicapoc: a Gardos channel blocker; structure in first source | ||
| quinidine | quinidine : A cinchona alkaloid consisting of cinchonine with the hydrogen at the 6-position of the quinoline ring substituted by methoxy. Quinidine: An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission. | cinchona alkaloid | alpha-adrenergic antagonist; anti-arrhythmia drug; antimalarial; drug allergen; EC 1.14.13.181 (13-deoxydaunorubicin hydroxylase) inhibitor; EC 3.6.3.44 (xenobiotic-transporting ATPase) inhibitor; muscarinic antagonist; P450 inhibitor; potassium channel blocker; sodium channel blocker |
| (2'-(benzyloxycarbonylaminomethyl)biphenyl-2-carboxylic acid 2-(2-pyridyl)ethylamide) | biphenyls | ||
| acacetin | 5,7-dihydroxy-4'-methoxyflavone : A monomethoxyflavone that is the 4'-methyl ether derivative of apigenin. | dihydroxyflavone; monomethoxyflavone | anticonvulsant; plant metabolite |
| clathrodin | clathrodin: structure given in first source; isolated from marine sponges of the genus Agelas | ||
| oroidin | oroidin: from marine sponges of the genus Agelas; structure in first source | pyrroles; secondary carboxamide | metabolite |
| hymenidin | hymenidin: serotonergic receptor antagonist from Okinawan marine sponge Hymeniacidon; structure given in first source | ||
| a 1899 | A 1899: a TASK-1 potassium channel blocker; structure in first source | ||
| [[(1S,2S,5R)-5-methyl-2-propan-2-ylcyclohexyl]-phenylphosphoryl]benzene | monoterpenoid |