Page last updated: 2024-10-24

sarcoplasm

Definition

Target type: cellularcomponent

The cytoplasm of a muscle cell; includes the sarcoplasmic reticulum. [ISBN:0198547684]

Sarcoplasm is the cytoplasm of muscle cells, specifically skeletal, cardiac, and smooth muscle cells. It is a highly specialized intracellular environment that plays a crucial role in muscle contraction and relaxation. The sarcoplasm contains a complex mixture of proteins, enzymes, ions, and other molecules essential for muscle function.

**Key Components of Sarcoplasm:**

* **Myofibrils:** These are the fundamental contractile units of muscle cells, composed of repeating sarcomeres. Sarcomeres are the basic structural and functional units of muscle tissue, responsible for muscle contraction.
* **Sarcoplasmic Reticulum (SR):** This is a specialized endoplasmic reticulum that plays a vital role in calcium regulation. It forms a network of interconnected tubules and cisternae surrounding the myofibrils. The SR stores and releases calcium ions (Ca2+), which are essential for triggering muscle contraction.
* **Transverse Tubules (T-tubules):** These are invaginations of the sarcolemma (muscle cell membrane) that extend deep into the muscle fiber, forming a network that encircles the myofibrils. T-tubules facilitate the rapid transmission of electrical signals (action potentials) from the sarcolemma to the SR, triggering the release of Ca2+ and initiating muscle contraction.
* **Glycogen Granules:** Muscle cells store glycogen, a branched form of glucose, as an energy reserve. Glycogen is broken down into glucose during muscle activity, providing fuel for muscle contraction.
* **Mitochondria:** These are the powerhouses of the cell, responsible for ATP production through oxidative phosphorylation. Muscle cells have a high density of mitochondria to meet the energy demands of contraction.
* **Enzymes:** The sarcoplasm contains numerous enzymes involved in various metabolic pathways, including glycolysis, the Krebs cycle, and oxidative phosphorylation. These enzymes play critical roles in energy production, protein synthesis, and muscle function.
* **Ions:** The sarcoplasm maintains specific concentrations of ions, such as potassium (K+), sodium (Na+), calcium (Ca2+), and chloride (Cl-), which are crucial for electrical signaling, membrane potential, and muscle contraction.

**Functional Significance of Sarcoplasm:**

The sarcoplasm provides a specialized environment for muscle cell function, facilitating:

* **Muscle Contraction:** The sarcoplasm contains the myofibrils, SR, and T-tubules, which work together to regulate Ca2+ release and enable muscle contraction.
* **Energy Production:** The high density of mitochondria in the sarcoplasm ensures an adequate supply of ATP to power muscle contraction.
* **Metabolic Processes:** The sarcoplasm contains enzymes involved in various metabolic pathways, supporting muscle function and energy production.
* **Signal Transduction:** The sarcoplasm facilitates the transmission of electrical signals from the sarcolemma to the SR, triggering muscle contraction.

In summary, the sarcoplasm is a vital component of muscle cells, providing a specialized environment that supports the complex processes of muscle contraction, relaxation, and energy metabolism. Its unique composition and structure contribute significantly to the overall function of skeletal, cardiac, and smooth muscle tissues.'
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Proteins (4)

ProteinDefinitionTaxonomy
Sodium channel protein type 3 subunit alphaA sodium channel protein type 3 subunit alpha that is encoded in the genome of human. [PRO:WCB, UniProtKB:Q9NY46]Homo sapiens (human)
ELAV-like protein 1An ELAV-like protein 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q15717]Homo sapiens (human)
MyoglobinA myoglobin that is encoded in the genome of human. [PRO:DNx, UniProtKB:P02144]Homo sapiens (human)
B-cell CLL/lymphoma 9 proteinA B-cell CLL/lymphoma 9 protein that is encoded in the genome of human. [PRO:DNx, UniProtKB:O00512]Homo sapiens (human)

Compounds (37)

CompoundDefinitionClassesRoles
phenytoinimidazolidine-2,4-dioneanticonvulsant;
drug allergen;
sodium channel blocker;
teratogenic agent
acetaminophenAcetaminophen: Analgesic antipyretic derivative of acetanilide. It has weak anti-inflammatory properties and is used as a common analgesic, but may cause liver, blood cell, and kidney damage.

paracetamol : A member of the class of phenols that is 4-aminophenol in which one of the hydrogens attached to the amino group has been replaced by an acetyl group.
acetamides;
phenols
antipyretic;
cyclooxygenase 1 inhibitor;
cyclooxygenase 2 inhibitor;
cyclooxygenase 3 inhibitor;
environmental contaminant;
ferroptosis inducer;
geroprotector;
hepatotoxic agent;
human blood serum metabolite;
non-narcotic analgesic;
non-steroidal anti-inflammatory drug;
xenobiotic
amiodaroneamiodarone : A member of the class of 1-benzofurans that is 1-benzofuran substituted by a butyl group at position 2 and a 4-[2-(diethylamino)ethoxy]-3,5-diiodobenzoyl group at position 3. It is a cardiovascular drug used for the treatment of cardiac dysrhythmias.

Amiodarone: An antianginal and class III antiarrhythmic drug. It increases the duration of ventricular and atrial muscle action by inhibiting POTASSIUM CHANNELS and VOLTAGE-GATED SODIUM CHANNELS. There is a resulting decrease in heart rate and in vascular resistance.
1-benzofurans;
aromatic ketone;
organoiodine compound;
tertiary amino compound
cardiovascular drug
amitriptylineamitriptyline : An organic tricyclic compound that is 10,11-dihydro-5H-dibenzo[a,d][7]annulene substituted by a 3-(dimethylamino)propylidene group at position 5.

Amitriptyline: Tricyclic antidepressant with anticholinergic and sedative properties. It appears to prevent the re-uptake of norepinephrine and serotonin at nerve terminals, thus potentiating the action of these neurotransmitters. Amitriptyline also appears to antagonize cholinergic and alpha-1 adrenergic responses to bioactive amines.
carbotricyclic compound;
tertiary amine
adrenergic uptake inhibitor;
antidepressant;
environmental contaminant;
tropomyosin-related kinase B receptor agonist;
xenobiotic
chlorpromazinechlorpromazine : A substituted phenothiazine in which the ring nitrogen at position 10 is attached to C-3 of an N,N-dimethylpropanamine moiety.

Chlorpromazine: The prototypical phenothiazine antipsychotic drug. Like the other drugs in this class chlorpromazine's antipsychotic actions are thought to be due to long-term adaptation by the brain to blocking DOPAMINE RECEPTORS. Chlorpromazine has several other actions and therapeutic uses, including as an antiemetic and in the treatment of intractable hiccup.
organochlorine compound;
phenothiazines;
tertiary amine
anticoronaviral agent;
antiemetic;
dopaminergic antagonist;
EC 3.4.21.26 (prolyl oligopeptidase) inhibitor;
phenothiazine antipsychotic drug
cifenlinediarylmethane
haloperidolhaloperidol : A compound composed of a central piperidine structure with hydroxy and p-chlorophenyl substituents at position 4 and an N-linked p-fluorobutyrophenone moiety.

Haloperidol: A phenyl-piperidinyl-butyrophenone that is used primarily to treat SCHIZOPHRENIA and other PSYCHOSES. It is also used in schizoaffective disorder, DELUSIONAL DISORDERS, ballism, and TOURETTE SYNDROME (a drug of choice) and occasionally as adjunctive therapy in INTELLECTUAL DISABILITY and the chorea of HUNTINGTON DISEASE. It is a potent antiemetic and is used in the treatment of intractable HICCUPS. (From AMA Drug Evaluations Annual, 1994, p279)
aromatic ketone;
hydroxypiperidine;
monochlorobenzenes;
organofluorine compound;
tertiary alcohol
antidyskinesia agent;
antiemetic;
dopaminergic antagonist;
first generation antipsychotic;
serotonergic antagonist
lidocainelidocaine : 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
imipramineimipramine : A dibenzoazepine that is 5H-dibenzo[b,f]azepine substituted by a 3-(dimethylamino)propyl group at the nitrogen atom.

Imipramine: The prototypical tricyclic antidepressant. It has been used in major depression, dysthymia, bipolar depression, attention-deficit disorders, agoraphobia, and panic disorders. It has less sedative effect than some other members of this therapeutic group.
dibenzoazepineadrenergic uptake inhibitor;
antidepressant;
EC 3.4.21.26 (prolyl oligopeptidase) inhibitor
lamotrigine1,2,4-triazines;
dichlorobenzene;
primary arylamine
anticonvulsant;
antidepressant;
antimanic drug;
calcium channel blocker;
EC 3.4.21.26 (prolyl oligopeptidase) inhibitor;
environmental contaminant;
excitatory amino acid antagonist;
geroprotector;
non-narcotic analgesic;
xenobiotic
mexiletinemexiletine : An aromatic ether which is 2,6-dimethylphenyl ether of 2-aminopropan-1-ol.

Mexiletine: Antiarrhythmic agent pharmacologically similar to LIDOCAINE. It may have some anticonvulsant properties.
aromatic ether;
primary amino compound
anti-arrhythmia drug
nifedipineNifedipine: 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
nitrendipinenitrendipine : A dihydropyridine that is 1,4-dihydropyridine substituted by methyl groups at positions 2 and 6, a 3-nitrophenyl group at position 4, a ethoxycarbonyl group at position 3 and a methoxycarbonyl group at position 5. It is a calcium-channel blocker used in the treatment of hypertension.

Nitrendipine: A calcium channel blocker with marked vasodilator action. It is an effective antihypertensive agent and differs from other calcium channel blockers in that it does not reduce glomerular filtration rate and is mildly natriuretic, rather than sodium retentive.
C-nitro compound;
dicarboxylic acids and O-substituted derivatives;
diester;
dihydropyridine;
ethyl ester;
methyl ester
antihypertensive agent;
calcium channel blocker;
geroprotector;
vasodilator agent
phenobarbitalphenobarbital : A member of the class of barbiturates, the structure of which is that of barbituric acid substituted at C-5 by ethyl and phenyl groups.

Phenobarbital: A barbituric acid derivative that acts as a nonselective central nervous system depressant. It potentiates GAMMA-AMINOBUTYRIC ACID action on GABA-A RECEPTORS, and modulates chloride currents through receptor channels. It also inhibits glutamate induced depolarizations.
barbituratesanticonvulsant;
drug allergen;
excitatory amino acid antagonist;
sedative
tetracainetetracaine : A benzoate ester in which 4-N-butylbenzoic acid and 2-(dimethylamino)ethanol have combined to form the ester bond; a local ester anaesthetic (ester caine) used for surface and spinal anaesthesia.

Tetracaine: A potent local anesthetic of the ester type used for surface and spinal anesthesia.
benzoate ester;
tertiary amino compound
local anaesthetic
naphthazarinnaphthazarin : A naphthoquinone that is 1,4-naphthoquinone in which the hydrogens at positions 5 and 8 are replaced by hydroxy groups.

naphthazarin: fish toxin; isolated for first time from the walnut onigurmi, Juglans mandshurica maxim var. Sieboldiana Makino; structure
hydroxy-1,4-naphthoquinoneacaricide;
antibacterial agent;
antineoplastic agent;
apoptosis inducer;
geroprotector;
plant metabolite
pimozidepimozide : A member of the class of benzimidazoles that is 1,3-dihydro-2H-benzimidazol-2-one in which one of the nitrogens is substituted by a piperidin-4-yl group, which in turn is substituted on the nitrogen by a 4,4-bis(p-fluorophenyl)butyl group.

Pimozide: A diphenylbutylpiperidine that is effective as an antipsychotic agent and as an alternative to HALOPERIDOL for the suppression of vocal and motor tics in patients with Tourette syndrome. Although the precise mechanism of action is unknown, blockade of postsynaptic dopamine receptors has been postulated. (From AMA Drug Evaluations Annual, 1994, p403)
benzimidazoles;
heteroarylpiperidine;
organofluorine compound
antidyskinesia agent;
dopaminergic antagonist;
first generation antipsychotic;
H1-receptor antagonist;
serotonergic antagonist
diltiazemdiltiazem : A 5-[2-(dimethylamino)ethyl]-2-(4-methoxyphenyl)-4-oxo-2,3,4,5-tetrahydro-1,5-benzothiazepin-3-yl acetate in which both stereocentres have S configuration. A calcium-channel blocker and vasodilator, it is used as the hydrochloride in the management of angina pectoris and hypertension.

Diltiazem: A benzothiazepine derivative with vasodilating action due to its antagonism of the actions of CALCIUM ion on membrane functions.
5-[2-(dimethylamino)ethyl]-2-(4-methoxyphenyl)-4-oxo-2,3,4,5-tetrahydro-1,5-benzothiazepin-3-yl acetateantihypertensive agent;
calcium channel blocker;
vasodilator agent
sertindolesertindole : 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
mibefradilMibefradil: A benzimidazoyl-substituted tetraline that selectively binds and inhibits CALCIUM CHANNELS, T-TYPE.tetralinsT-type calcium channel blocker
salvinsalvin: a biocyclic diterpenoid; from sage and rosemary (Lamiaceae)abietane diterpenoid;
carbotricyclic compound;
catechols;
monocarboxylic acid
angiogenesis modulating agent;
anti-inflammatory agent;
antineoplastic agent;
antioxidant;
apoptosis inducer;
food preservative;
HIV protease inhibitor;
plant metabolite
tedisamiltedisamil : A member of the class of diazabicyclononanes that is (1s,5s)-3,7-diazaspiro[bicyclo[3.3.1]nonane-9,1'-cyclopentane] in which the hydrogens at positions 3 and 7 are replaced by cyclopropylmethyl groups. It is a potassium channel blocker and an antiarrhythmic agent currently currently in development for the treatment of atrial fibrillation.
uk 68798aromatic ether;
sulfonamide;
tertiary amino compound
anti-arrhythmia drug;
potassium channel blocker
5,8-dihydroxy-3-methyl-4-(9h)-naphtho(2,3-c)furanone5,8-dihydroxy-3-methyl-4-(9H)-naphtho(2,3-c)furanone: isolated from Micromonospora sp. KY7123; structure given in first source
n-methylpiperidin-4-yl propionate
cns 5161CNS 5161: structure in first source
senicapocsenicapoc: a Gardos channel blocker; structure in first source
ica-121431ICA-121431: structure in first source
quercetin7-hydroxyflavonol;
pentahydroxyflavone
antibacterial agent;
antineoplastic agent;
antioxidant;
Aurora kinase inhibitor;
chelator;
EC 1.10.99.2 [ribosyldihydronicotinamide dehydrogenase (quinone)] inhibitor;
geroprotector;
phytoestrogen;
plant metabolite;
protein kinase inhibitor;
radical scavenger
2-ethyl-5-methoxy-n,n-dimethyltryptamine2-ethyl-5-methoxy-N,N-dimethyltryptamine: a 5-HT(6) receptor agonist; structure in first source
5-chloro-2-methyl-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1h-indole5-chloro-2-methyl-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole: a 5-HT6 agonist; structure in first sourceindoles
tetrodotoxin
Dihydrotanshinone Idihydrotanshinone I: extracted from Radix Salviaeabietane diterpenoidanticoronaviral agent
a 803467A 803467: an Nav1.8 sodium channel blocker; structure in first source
cnv1014802vixotrigine: a sodium channel blocker
saxitoxinsaxitoxin : An alkaloid isolated from the marine dinoflagellates and cyanobacteria that causes paralytic shellfish poisoning.

Saxitoxin: A compound that contains a reduced purine ring system but is not biosynthetically related to the purine alkaloids. It is a poison found in certain edible mollusks at certain times; elaborated by GONYAULAX and consumed by mollusks, fishes, etc. without ill effects. It is neurotoxic and causes RESPIRATORY PARALYSIS and other effects in MAMMALS, known as paralytic SHELLFISH poisoning.
alkaloid;
carbamate ester;
guanidines;
ketone hydrate;
paralytic shellfish toxin;
pyrrolopurine
cyanotoxin;
marine metabolite;
neurotoxin;
sodium channel blocker;
toxin
ajmaline