Target type: biologicalprocess
Any process that activates or increases the frequency, rate or extent of membrane repolarization during ventricular cardiac muscle cell action potential. [GO_REF:0000058, GOC:BHF, GOC:BHF_miRNA, GOC:mtg_cardiac_conduct_nov11, GOC:rph, GOC:TermGenie, PMID:19893015]
Positive regulation of membrane repolarization during ventricular cardiac muscle cell action potential is a critical process that ensures the proper function of the heart. It involves a series of coordinated events that restore the electrical potential across the membrane of a ventricular cardiac muscle cell to its resting state after depolarization, which is the initial phase of the action potential.
The repolarization phase is characterized by a gradual decrease in membrane potential, returning the cell from a positive to a negative charge. This is achieved through the coordinated opening and closing of specific ion channels in the cell membrane.
1. **Sodium Channels Inactivate:** Following the initial depolarization phase, sodium channels responsible for the influx of sodium ions rapidly inactivate. This prevents further influx of sodium ions, halting the depolarizing current.
2. **Potassium Channels Activate:** At the same time, potassium channels, specifically the delayed rectifier potassium channels (Ku003csubu003evu003c/subu003e) begin to open. This allows potassium ions to flow out of the cell, driven by their concentration gradient. The outward flow of potassium ions counteracts the inward flow of sodium ions, contributing to the gradual decrease in membrane potential.
3. **Transient Outward Potassium Current:** Another type of potassium channel, known as the transient outward potassium current (Iu003csubu003etou003c/subu003e), plays a role in early repolarization. These channels open rapidly and contribute to the initial repolarization phase.
4. **Calcium Channels Close:** While not as prominent as sodium and potassium channels in repolarization, calcium channels involved in the plateau phase also begin to close. This further reduces the influx of calcium ions, contributing to the decrease in membrane potential.
5. **Repolarization Completion:** The continued outflow of potassium ions eventually restores the negative membrane potential, bringing the cell back to its resting state.
The precise timing and regulation of these ion channel activities are crucial for proper repolarization. Disruptions in these processes can lead to various cardiac arrhythmias, potentially resulting in heart failure or even sudden cardiac death.
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| Protein | Definition | Taxonomy |
|---|---|---|
| Nitric oxide synthase, brain | A nitric oxide synthase 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P29475] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| imidazole | 1H-imidazole : An imidazole tautomer which has the migrating hydrogen at position 1. imidazole: RN given refers to parent cpd | imidazole | |
| s,s'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea | S,S'-1,4-phenylene-bis(1,2-ethanediyl)bis-isothiourea: structure in first source | ||
| n-(3-(aminomethyl)benzyl)acetamidine | N-(3-(aminomethyl)benzyl)acetamidine: structure in first source N-[3-(aminomethyl)benzyl]acetamidine : An aralkylamine that is Nbenzylacetamidine substituted at position 3 on the benzene ring by an aminomethyl group. An inhibitor of nitric oxide synthase. | aralkylamine; carboxamidine; primary amino compound | angiogenesis inhibitor; EC 1.14.13.39 (nitric oxide synthase) inhibitor; geroprotector |
| 2-amino-4-picoline | 2-amino-4-picoline: RN given refers to parent cpd | ||
| 3-bromo-7-nitroindazole | |||
| 7-nitroindazole | 7-nitroindazole: an inhibitor of nitric oxide synthase; exhibits anti-nociceptive activity without increasing blood pressure | ||
| beta-aminoethyl isothiourea | beta-Aminoethyl Isothiourea: A radiation-protective agent that can inhibit DNA damage by binding to the DNA. It also increases the susceptibility of blood cells to complement-mediated lysis. | ||
| pimagedine | aminoguanidine : A one-carbon compound whose unique structure renders it capable of acting as a derivative of hydrazine, guanidine or formamide. pimagedine: diamine oxidase & nitric oxide synthase inhibitor; an advanced glycosylation end product inhibitor; used in the treatment of diabetic complications; structure | guanidines; one-carbon compound | EC 1.14.13.39 (nitric oxide synthase) inhibitor; EC 1.4.3.4 (monoamine oxidase) inhibitor |
| 2-aminothiazole | 1,3-thiazol-2-amine : A primary amino compound that is 1,3-thiazole substituted by an amino group at position 2. 2-aminothiazole: RN given refers to parent cpd; structure | 1,3-thiazoles; primary amino compound | |
| s-ethyl n-(4-(trifluoromethyl)phenyl)isothiourea | S-ethyl N-(4-(trifluoromethyl)phenyl)isothiourea: structure in first source | ||
| etiron | etiron: a nitric oxide synthase inhibitor; RN given refers to parent cpd; structure | ||
| s-methylisothiopseudouronium | S-methylisothiopseudouronium: inhibits nitric oxide synthase; structure in first source | ||
| arginine | arginine : An alpha-amino acid that is glycine in which the alpha-is substituted by a 3-guanidinopropyl group. Arginine: An essential amino acid that is physiologically active in the L-form. | arginine; glutamine family amino acid; L-alpha-amino acid; proteinogenic amino acid | biomarker; Escherichia coli metabolite; micronutrient; mouse metabolite; nutraceutical |
| indazoles | Indazoles: A group of heterocyclic aromatic organic compounds consisting of the fusion of BENZENE and PYRAZOLES. | indazole | |
| citrulline | citrulline : The parent compound of the citrulline class consisting of ornithine having a carbamoyl group at the N(5)-position. | amino acid zwitterion; citrulline | Daphnia magna metabolite; EC 1.14.13.39 (nitric oxide synthase) inhibitor; Escherichia coli metabolite; human metabolite; micronutrient; mouse metabolite; nutraceutical; plant metabolite; protective agent; Saccharomyces cerevisiae metabolite |
| alpha-aminopyridine | alpha-aminopyridine: RN given refers to parent cpd; structure in Merck Index, 9th ed, #485 aminopyridine : Compounds containing a pyridine skeleton substituted by one or more amine groups. | ||
| 2-amino-3-methylpyridine | 2-amino-3-methylpyridine: structure in first source | ||
| 2-aminothiazoline | 2-aminothiazoline: RN given refers to parent cpd; structure in first source & in Negwer, 5th ed, #97 4,5-dihydro-1,3-thiazol-2-amine : A 1,3-thiazole that is 4,5-dihydro-1,3-thiazole substituted by an amino group at position 2. | 1,3-thiazoles; primary amino compound | |
| 5-nitroindazole | |||
| 6-nitroindazole | |||
| ng-nitroarginine methyl ester | NG-Nitroarginine Methyl Ester: A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension. | alpha-amino acid ester; L-arginine derivative; methyl ester; N-nitro compound | EC 1.14.13.39 (nitric oxide synthase) inhibitor |
| n-(4-nitrophenacyl)imidazole | N-(4-nitrophenacyl)imidazole: structure in first source | ||
| 1-aminoisoquinoline | |||
| 6-aminoindazole | 6-aminoindazole: depresses gastric acid secretion; structure given in first source | indazoles | |
| 1-phenylimidazole | 1-phenylimidazole: ligand for cytochrome P-450 & inhibitor of microsomal oxidation | ||
| 3-indazolinone | 3-indazolinone: structure given in first source | ||
| 5-aminoindazole | |||
| 3,5-dimethylpyrazole-1-carboxamidine | 3,5-dimethylpyrazole-1-carboxamidine: guanidinating reagent for proteins; RN given refers to parent cpd | ||
| s-methylthiocitrulline | S-methyl-L-thiocitrulline : An L-arginine derivative in which the guanidino NH2 group of L-arginine is replaced by a methylsufanyl group. S-methylthiocitrulline: a nitric oxide synthase inhibitor; structure in first source | imidothiocarbamic ester; L-arginine derivative; L-ornithine derivative; non-proteinogenic L-alpha-amino acid | EC 1.14.13.39 (nitric oxide synthase) inhibitor; neuroprotective agent |
| n(g)-iminoethylornithine | L-alpha-amino acid | ||
| n,n-dimethylarginine | N,N-dimethylarginine: asymmetric dimethylarginine; do not confuse with N,N'-dimethylarginine N(omega),N(omega)-dimethyl-L-arginine : A L-arginine derivative having two methyl groups both attached to the primary amino moiety of the guanidino group. | dimethylarginine; guanidines; L-arginine derivative; non-proteinogenic L-alpha-amino acid | EC 1.14.13.39 (nitric oxide synthase) inhibitor |
| omega-n-methylarginine | N(omega)-methyl-L-arginine : A L-arginine derivative with a N(omega)-methyl substituent. omega-N-Methylarginine: A competitive inhibitor of nitric oxide synthetase. | amino acid zwitterion; arginine derivative; guanidines; L-arginine derivative; non-proteinogenic L-alpha-amino acid | |
| ng-nitroarginine methyl ester | N(gamma)-nitro-L-arginine methyl ester hydrochloride : A hydrochloride obtained by combining N(gamma)-nitro-L-arginine methyl ester with one equivalent of hydrochloric acid. | hydrochloride | EC 1.14.13.39 (nitric oxide synthase) inhibitor |
| delta-n-methylarginine | N(5)-methyl-L-arginine : A non-proteinogenic L-alpha-amino acid that is L-arginine substituted by a methyl group at N(5)-position. | guanidines; L-arginine derivative; non-proteinogenic L-alpha-amino acid | |
| 2-amino-5,6-dihydro-4h-1,3-thiazine | 2-amino-5,6-dihydro-4H-1,3-thiazine: RN given refers to parent cpd | ||
| 2-amino-5-methylthiazole | 2-amino-5-methylthiazole: binds the W191G cavity of E coli cytochrome c peroxidase | ||
| nitroarginine | N(gamma)-nitro-L-arginine : An L-arginine derivative that is L-arginine in which the terminal nitrogen of the guanidyl group is replaced by a nitro group. Nitroarginine: An inhibitor of nitric oxide synthetase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. (Neurochem Res 1995:200(4):451-6) | guanidines; L-arginine derivative; N-nitro compound; non-proteinogenic L-alpha-amino acid | |
| vinyl-l-nio | |||
| arl 17477 | |||
| n(6)-(1-iminoethyl)lysine | N(6)-acetimidoyl-L-lysine : An L-lysine derivative that is L-lysine in which one of the hydrogens attached to N(6) is substituted by an acetimidoyl group | L-lysine derivative; non-proteinogenic L-alpha-amino acid | |
| pyrazole-1-carboxamidine | pyrazole-1-carboxamidine: structure given in first source | ||
| gw 274150 | |||
| 1-(4-(3-bromophenoxy)butyl)-1h-imidazole | 1-(4-(3-bromophenoxy)butyl)-1H-imidazole: structure in first source | ||
| sapropterin | (6R)-5,6,7,8-tetrahydrobiopterin : A 5,6,7,8-tetrahydrobiopterin in which the stereocentre at position 6 has R-configuration. sapropterin : A tetrahydropterin that is 2-amino-5,6,7,8-tetrahydropteridin-4(3H)-one in which a hydrogen at position 6 is substituted by a 1,2-dihydroxypropyl group (6R,1'R,2'S-enantiomer). sapropterin: RN given refers to parent cpd; co-factor required for catalytic activity of nitric oxide synthases | 5,6,7,8-tetrahydrobiopterin | coenzyme; cofactor; diagnostic agent; human metabolite |
| 6-hydroxymethylpterin |