Sarcolemma
Dystrophin
Muscular Dystrophy, Animal
Utrophin
Myocardium
Dystrophin-Associated Proteins
Mice, Inbred mdx
Dystroglycans
Caveolin 3
Muscle, Skeletal
Sarcoglycans
Muscular Dystrophies
Muscle Proteins
Muscle Fibers, Skeletal
4-Nitrophenylphosphatase
Sodium-Potassium-Exchanging ATPase
Muscular Dystrophy, Duchenne
Calcium
Nitric Oxide Synthase Type I
Costameres
Sarcoplasmic Reticulum
Freeze Fracturing
Shadowing (Histology)
Sodium-Calcium Exchanger
Caveolins
Wheat Germ Agglutinins
Sodium
Microscopy, Electron
Plectin
Myofibrils
Myocytes, Cardiac
Dogs
Heart Ventricles
Cytoskeletal Proteins
Aquaporin 4
Chemistry, Bioinorganic
Calcium-Transporting ATPases
Rabbits
Fluorescent Antibody Technique
Vinculin
Membrane Proteins
Desmin
Muscle Contraction
Glucose Transporter Type 4
Cell Fractionation
Muscle Fibers, Fast-Twitch
Receptors, Albumin
Saxitoxin
Spectrin
Ouabain
Dihydroalprenolol
Myotonia
Cell Membrane
Nitrendipine
Annexin A6
Calcium-Binding Proteins
Subcellular Fractions
Cocos
Dystrophin-Associated Protein Complex
Adenoviral gene transfer of the human V2 vasopressin receptor improves contractile force of rat cardiomyocytes. (1/1361)
BACKGROUND: In congestive heart failure, high systemic levels of the hormone arginine vasopressin (AVP) result in vasoconstriction and reduced cardiac contractility. These effects are mediated by the V1 vasopressin receptor (V1R) coupled to phospholipase C beta-isoforms. The V2 vasopressin receptor (V2R), which promotes activation of the Gs/adenylyl cyclase system, is physiologically expressed in the kidney but not in the myocardium. Expression of a recombinant V2R (rV2R) in the myocardium could result in a positive inotropic effect via the endogenous high concentrations of AVP in heart failure. METHODS AND RESULTS: A recombinant adenovirus encoding the human V2R (Ad-V2R) was tested for its ability to modulate the cardiac Gs/adenylyl cyclase system and to potentiate contractile force in rat ventricular cardiomyocytes and in H9c2 cardiomyoblasts. Ad-V2R infection resulted in a virus concentration-dependent expression of the transgene and led to a marked increase in cAMP formation in rV2R-expressing cardiomyocytes after exposure to AVP. Single-cell shortening measurements showed a significant agonist-induced contraction amplitude enhancement, which was blocked by the V2R antagonist, SR 121463A. Pretreatment of Ad-V2R-infected cardiomyocytes with AVP led to desensitization of the rV2R after short-term agonist exposure but did not lead to further loss of receptor function or density after long-term agonist incubation, thus demonstrating resistance of the rV2R to downregulation. CONCLUSIONS: Adenoviral gene transfer of the V2R in cardiomyocytes can modulate the endogenous adenylyl cyclase-signal transduction cascade and can potentiate contraction amplitude in cardiomyocytes. Heterologous expression of cAMP-forming receptors in the myocardium could lead to novel strategies in congestive heart failure by bypassing the desensitized beta-adrenergic receptor signaling. (+info)Alterations of heart function and Na+-K+-ATPase activity by etomoxir in diabetic rats. (2/1361)
To examine the role of changes in myocardial metabolism in cardiac dysfunction in diabetes mellitus, rats were injected with streptozotocin (65 mg/kg body wt) to induce diabetes and were treated 2 wk later with the carnitine palmitoyltransferase inhibitor (carnitine palmitoyltransferase I) etomoxir (8 mg/kg body wt) for 4 wk. Untreated diabetic rats exhibited a reduction in heart rate, left ventricular systolic pressure, and positive and negative rate of pressure development and an increase in end-diastolic pressure. The sarcolemmal Na+-K+-ATPase activity was depressed and was associated with a decrease in maximal density of binding sites (Bmax) value for high-affinity sites for [3H]ouabain, whereas Bmax for low-affinity sites was unaffected. Treatment of diabetic animals with etomoxir partially reversed the depressed cardiac function with the exception of heart rate. The high serum triglyceride and free fatty acid levels were reduced, whereas the levels of glucose, insulin, and 3,3',-5-triiodo-L-thyronine were not affected by etomoxir in diabetic animals. The activity of Na+-K+-ATPase expressed per gram heart weight, but not per milligram sarcolemmal protein, was increased by etomoxir in diabetic animals. Furthermore, Bmax (per g heart wt) for both low-affinity and high-affinity binding sites in control and diabetic animals was increased by etomoxir treatment. Etomoxir treatment also increased the depressed left ventricular weight of diabetic rats and appeared to increase the density of the sarcolemma and transverse tubular system to normalize Na+-K+-ATPase activity. Therefore, a shift in myocardial substrate utilization may represent an important signal for improving the depressed cardiac function and Na+-K+-ATPase activity in diabetic rat hearts with impaired glucose utilization. (+info)A novel small protein associated with a conjugated trienoic chromophore from membranes of scallop adductor muscle: phosphorylation by protein kinase A. (3/1361)
Membranes enriched in sarcolemma from the cross-striated adductor muscle of the deep sea scallop have been found to contain a previously undescribed small protein of 6-8 kDa that can be released by treatment with organic solvent mixtures. This proteolipid co-purified with a non-amino acid chromophore containing a conjugated trienoic moiety. Although common in plants and algae, such a stable conjugated trienoic group is unusual for an animal cell. The N-terminal amino acid sequence of the protein was XEFQHGLFGXF/ADNIGLQ, which most strongly resembles sequences in the triacyl glycerol lipase precursor and the product of the human breast cancer susceptibility gene BRCA 1, but does not show similarity to previously described proteolipids. The protein was found to be one of the major substrates in its parent membrane for the catalytic subunit of protein kinase A, which may imply a regulatory function for this molecule. (+info)Pharmacological characterization of protein phosphatase activities in preparations from failing human hearts. (4/1361)
beta-Adrenoceptor stimulation acts in the heart in part by increasing the phosphorylation state of phospholamban and phospholemman. There is evidence that the beta-adrenoceptor-mediated increase in phospholamban phosphorylation is in part due to inhibition of type 1 phosphatases. The aim of the present study was to elucidate which phosphatases dephosphorylate phospholamban and phospholemman in the human heart. In the past, cardiac serine/threonine phosphatases have been studied using phosphorylase a as substrate. Here, type 1 and type 2A phosphatase activities were studied in preparations from failing human hearts using phosphorylated phospholamban and phospholemman as substrates. Phospholamban and phospholemman phosphatase activity was detectable in human cardiac homogenates. Moreover, using a heparin-Sepharose column, the catalytic subunits of type 1 and type 2A phosphatases could be separated from human ventricles. Okadaic acid and cantharidin inhibited phosphatase activities dephosphorylating phospholamban, phospholemman, and phosphorylase a in homogenates in a concentration-dependent manner. However, okadaic acid was more potent. Cantharidin inhibited type 2A and type 1 activities against all substrates studied with IC50 values <15 nM and >290 nM, respectively. Okadaic acid inhibited type 1 and type 2A phosphatase activities as effectively but 10-30 times more potently than cantharidin. This work provides evidence that in the human heart, type 1 and 2A phosphatases are involved in the dephosphorylation of phospholamban and phospholemman and could play a role in the effects of beta-adrenergic stimulation in the heart. (+info)Extensive but coordinated reorganization of the membrane skeleton in myofibers of dystrophic (mdx) mice. (5/1361)
We used immunofluorescence techniques and confocal imaging to study the organization of the membrane skeleton of skeletal muscle fibers of mdx mice, which lack dystrophin. beta-Spectrin is normally found at the sarcolemma in costameres, a rectilinear array of longitudinal strands and elements overlying Z and M lines. However, in the skeletal muscle of mdx mice, beta-spectrin tends to be absent from the sarcolemma over M lines and the longitudinal strands may be disrupted or missing. Other proteins of the membrane and associated cytoskeleton, including syntrophin, beta-dystroglycan, vinculin, and Na,K-ATPase are also concentrated in costameres, in control myofibers, and mdx muscle. They also distribute into the same altered sarcolemmal arrays that contain beta-spectrin. Utrophin, which is expressed in mdx muscle, also codistributes with beta-spectrin at the mutant sarcolemma. By contrast, the distribution of structural and intracellular membrane proteins, including alpha-actinin, the Ca-ATPase and dihydropyridine receptors, is not affected, even at sites close to the sarcolemma. Our results suggest that in myofibers of the mdx mouse, the membrane- associated cytoskeleton, but not the nearby myoplasm, undergoes widespread coordinated changes in organization. These changes may contribute to the fragility of the sarcolemma of dystrophic muscle. (+info)Membrane targeting and stabilization of sarcospan is mediated by the sarcoglycan subcomplex. (6/1361)
The dystrophin-glycoprotein complex (DGC) is a multisubunit complex that spans the muscle plasma membrane and forms a link between the F-actin cytoskeleton and the extracellular matrix. The proteins of the DGC are structurally organized into distinct subcomplexes, and genetic mutations in many individual components are manifested as muscular dystrophy. We recently identified a unique tetraspan-like dystrophin-associated protein, which we have named sarcospan (SPN) for its multiple sarcolemma spanning domains (Crosbie, R.H., J. Heighway, D.P. Venzke, J.C. Lee, and K.P. Campbell. 1997. J. Biol. Chem. 272:31221-31224). To probe molecular associations of SPN within the DGC, we investigated SPN expression in normal muscle as a baseline for comparison to SPN's expression in animal models of muscular dystrophy. We show that, in addition to its sarcolemma localization, SPN is enriched at the myotendinous junction (MTJ) and neuromuscular junction (NMJ), where it is a component of both the dystrophin- and utrophin-glycoprotein complexes. We demonstrate that SPN is preferentially associated with the sarcoglycan (SG) subcomplex, and this interaction is critical for stable localization of SPN to the sarcolemma, NMJ, and MTJ. Our experiments indicate that assembly of the SG subcomplex is a prerequisite for targeting SPN to the sarcolemma. In addition, the SG- SPN subcomplex functions to stabilize alpha-dystroglycan to the muscle plasma membrane. Taken together, our data provide important information about assembly and function of the SG-SPN subcomplex. (+info)Muscle contractile activity increases fatty acid metabolism and transport and FAT/CD36. (7/1361)
We have examined whether 1) fatty acid (FA) uptake, 2) FA transporter expression, and 3) FA metabolism are increased when the oxidative capacity of skeletal muscle is increased. The oxidative capacities of red and white tibialis anterior and extensor digitorum longus muscles were increased via chronic stimulation (10 Hz, 24 h/day for 7 days). The contralateral muscles served as controls. After 7 days of increased muscle activity 1) palmitate uptake by giant sarcolemmal vesicles was increased twofold (P < 0.05), 2) the expression of FA translocase (FAT)/CD36 was increased at both the mRNA (3.2- to 10-fold) and protein (3.4-fold) levels, and 3) palmitate oxidation and esterification into triacylglycerols and phospholipids were increased 1.5-, 2.7-, and 1.7-fold, respectively (P < 0.05). These data show that when the oxidative capacity of muscle is increased, there is a parallel increase in the rate of FA transport and FA transporters at the sarcolemmal membrane, which is associated with the enhanced expression of the membrane transporter FAT/CD36. (+info)Inverse agonist activity of pirenzepine at M2 muscarinic acetylcholine receptors. (8/1361)
1. The intrinsic properties of muscarinic ligands were studied through their binding properties and their abilities to modulate the GTPase activity of G proteins coupled to muscarinic M2 receptors in pig atrial sarcolemma. 2. Competition binding experiments were performed with [3H]-oxotremorine-M to assess the affinity of receptors coupled to G proteins (R*), with [3H]-N-methylscopolamine ([3H]-NMS) to estimate the affinities of coupled and uncoupled receptors (R*+R) and with [3H]-NMS in the presence of GppNHp to assess the affinity of uncoupled receptors (R). 3. The ranking of Ki values for the agonist carbachol was R*<Sarcolemma is the medical term for the cell membrane that surrounds a muscle fiber or a skeletal muscle cell. It is responsible for providing protection and structure to the muscle fiber, as well as regulating the movement of ions and other molecules in and out of the cell. The sarcolemma plays a crucial role in the excitation-contraction coupling process that allows muscles to contract and relax.
The sarcolemma is composed of two main layers: the outer plasma membrane, which is similar to the cell membranes of other cells, and the inner basal lamina, which provides structural support and helps to anchor the muscle fiber to surrounding tissues. The sarcolemma also contains various ion channels, receptors, and transporters that are involved in regulating muscle function and communication with other cells.
Damage to the sarcolemma can lead to a variety of muscle disorders, including muscular dystrophy and myasthenia gravis.
Dystrophin is a protein that provides structural stability to muscle fibers. It is an essential component of the dystrophin-glycoprotein complex, which helps maintain the integrity of the sarcolemma (the membrane surrounding muscle cells) during muscle contraction and relaxation. Dystrophin plays a crucial role in connecting the cytoskeleton of the muscle fiber to the extracellular matrix, allowing for force transmission and protecting the muscle cell from damage.
Mutations in the DMD gene, which encodes dystrophin, can lead to various forms of muscular dystrophy, including Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). In DMD, a severe form of the disease, genetic alterations typically result in little or no production of functional dystrophin, causing progressive muscle weakness, wasting, and degeneration. In BMD, a milder form of the disorder, partially functional dystrophin is produced, leading to less severe symptoms and later onset of the disease.
I'm sorry for any confusion, but "Muscular Dystrophy, Animal" is not a standard medical term. Muscular Dystrophy is a group of genetic disorders that cause progressive weakness and loss of muscle mass. They are primarily human diseases and there are no known animal models of muscular dystrophy that directly correspond to any type of muscular dystrophy in humans.
However, scientists often use animals (like mice, dogs, and cats) as models for human diseases, including various types of muscular dystrophies. These animal models are used to study the disease process and to test potential treatments. For example, the mdx mouse is a well-known model of Duchenne Muscular Dystrophy (DMD), which is caused by a mutation in the dystrophin gene. This mouse lacks the muscle protein dystrophin, similar to humans with DMD, and shows many of the same symptoms, making it a valuable tool for research.
Utrophin is a protein that is found in muscle cells. It is similar in structure and function to dystrophin, which is a protein that is deficient or abnormal in people with Duchenne and Becker muscular dystrophy. Utrophin is present in both fetal and adult muscle, but its expression is usually limited to the nerve endings of the muscle fibers. However, in certain conditions such as muscle injury or disease, utrophin can be upregulated and expressed more widely throughout the muscle fiber. Research has shown that increasing the levels of utrophin in muscle cells could potentially compensate for the lack of dystrophin and provide a therapeutic approach to treating muscular dystrophy.
The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.
The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.
Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.
Dystrophin-associated proteins (DAPs) are a group of structural and functional proteins that interact with dystrophin, a cytoskeletal protein found in muscle cells. Dystrophin helps to maintain the integrity of the muscle fiber membrane, or sarcolemma, during contractions. The dystrophin-associated protein complex (DAPC) includes dystroglycans, sarcoglycans, syntrophins, and dystrobrevins, among others.
Mutations in genes encoding DAPs can lead to various forms of muscular dystrophy, a group of genetic disorders characterized by progressive muscle weakness and degeneration. For example, mutations in the sarcoglycan gene can cause limb-girdle muscular dystrophy type 2C (LGMD2C), while defects in dystroglycan can result in congenital muscular dystrophy with mental retardation and structural brain abnormalities.
In summary, DAPs are a group of proteins that interact with dystrophin to maintain the stability and function of muscle fibers. Defects in these proteins can lead to various forms of muscular dystrophy.
'Mice, Inbred mdx' is a genetic strain of laboratory mice that are widely used as a model to study Duchenne muscular dystrophy (DMD), a severe and progressive muscle-wasting disorder in humans. The 'mdx' designation refers to the specific genetic mutation present in these mice, which is a point mutation in the gene encoding for dystrophin, a crucial protein involved in maintaining the structural integrity of muscle fibers.
Inbred mdx mice carry a spontaneous mutation in exon 23 of the dystrophin gene, resulting in the production of a truncated and nonfunctional form of the protein. This leads to a phenotype that closely resembles DMD in humans, including muscle weakness, degeneration, and fibrosis. The inbred nature of these mice ensures consistent genetic backgrounds and disease manifestations, making them valuable tools for studying the pathophysiology of DMD and testing potential therapies.
It is important to note that while the inbred mdx mouse model has been instrumental in advancing our understanding of DMD, it does not fully recapitulate all aspects of the human disease. Therefore, findings from these mice should be carefully interpreted and validated in more complex models or human studies before translating them into clinical applications.
Dystroglycans are a type of protein that play a crucial role in the structure and function of the muscle membrane (sarcolemma). They are an essential component of the dystrophin-glycoprotein complex, which helps maintain the stability and integrity of the sarcolemma during muscle contraction and relaxation.
Dystroglycans consist of two subunits: alpha-dystroglycan and beta-dystroglycan. Alpha-dystroglycan is a large, heavily glycosylated protein that extends from the intracellular space to the extracellular matrix, where it interacts with various extracellular matrix proteins such as laminin and agrin. Beta-dystroglycan, on the other hand, spans the muscle membrane and binds to dystrophin, a cytoskeletal protein that helps maintain the structural integrity of the sarcolemma.
Mutations in genes encoding for proteins involved in the glycosylation of alpha-dystroglycan can lead to a group of genetic disorders known as congenital muscular dystrophies, which are characterized by muscle weakness, hypotonia, and developmental delays. These disorders include Walker-Warburg syndrome, Fukuyama congenital muscular dystrophy, and Muscle-Eye-Brain disease, among others.
Caveolin 3 is a protein that is primarily expressed in muscle cells, including cardiac and skeletal muscles. It is the principal structural component of caveolae, which are small invaginations of the plasma membrane that function as specialized microdomains involved in various cellular processes such as signal transduction, cholesterol homeostasis, and endocytosis.
Caveolin 3 plays a critical role in muscle physiology by regulating several signaling pathways that are important for muscle function, including the nitric oxide signaling pathway. Mutations in the gene encoding caveolin 3 have been associated with various inherited muscle disorders, such as limb-girdle muscular dystrophy type 1C (LGMD1C), rippling muscle disease (RMD), and distal myopathies. These genetic conditions are characterized by progressive muscle weakness, wasting, and degeneration.
Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.
Sarcoglycans are a group of proteins that are part of the dystrophin-glycoprotein complex in muscle cells. This complex helps to maintain the structural integrity of the muscle fiber by forming a link between the cytoskeleton and the extracellular matrix. Sarcoglycans are located on the surface of the muscle fiber and play a critical role in protecting the muscle from damage during contraction.
There are four main sarcoglycans, known as alpha, beta, gamma, and delta-sarcoglycan. Mutations in any one of these proteins can lead to a group of genetic disorders known as the sarcoglycanopathies, which are characterized by progressive muscle weakness and wasting. The most severe form of this disorder is called limb-girdle muscular dystrophy type 2C (LGMD2C), which is caused by mutations in the gamma-sarcoglycan gene.
In addition to their role in muscle cells, sarcoglycans have also been found to be expressed in other tissues, including the brain and the lungs, suggesting that they may have additional functions beyond their structural role in muscle.
A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.
Muscular dystrophies are a group of genetic disorders that primarily affect skeletal muscles, causing progressive weakness and degeneration. They are characterized by the lack or deficiency of a protein called dystrophin, which is essential for maintaining the integrity of muscle fibers. The most common form is Duchenne muscular dystrophy (DMD), but there are many other types with varying symptoms and severity. Over time, muscle wasting and weakness can lead to disability and shortened lifespan, depending on the type and progression of the disease. Treatment typically focuses on managing symptoms, maintaining mobility, and supporting quality of life.
Muscle proteins are a type of protein that are found in muscle tissue and are responsible for providing structure, strength, and functionality to muscles. The two major types of muscle proteins are:
1. Contractile proteins: These include actin and myosin, which are responsible for the contraction and relaxation of muscles. They work together to cause muscle movement by sliding along each other and shortening the muscle fibers.
2. Structural proteins: These include titin, nebulin, and desmin, which provide structural support and stability to muscle fibers. Titin is the largest protein in the human body and acts as a molecular spring that helps maintain the integrity of the sarcomere (the basic unit of muscle contraction). Nebulin helps regulate the length of the sarcomere, while desmin forms a network of filaments that connects adjacent muscle fibers together.
Overall, muscle proteins play a critical role in maintaining muscle health and function, and their dysregulation can lead to various muscle-related disorders such as muscular dystrophy, myopathies, and sarcopenia.
Skeletal muscle fibers, also known as striated muscle fibers, are the type of muscle cells that make up skeletal muscles, which are responsible for voluntary movements of the body. These muscle fibers are long, cylindrical, and multinucleated, meaning they contain multiple nuclei. They are surrounded by a connective tissue layer called the endomysium, and many fibers are bundled together into fascicles, which are then surrounded by another layer of connective tissue called the perimysium.
Skeletal muscle fibers are composed of myofibrils, which are long, thread-like structures that run the length of the fiber. Myofibrils contain repeating units called sarcomeres, which are responsible for the striated appearance of skeletal muscle fibers. Sarcomeres are composed of thick and thin filaments, which slide past each other during muscle contraction to shorten the sarcomere and generate force.
Skeletal muscle fibers can be further classified into two main types based on their contractile properties: slow-twitch (type I) and fast-twitch (type II). Slow-twitch fibers have a high endurance capacity and are used for sustained, low-intensity activities such as maintaining posture. Fast-twitch fibers, on the other hand, have a higher contractile speed and force generation capacity but fatigue more quickly and are used for powerful, explosive movements.
4-Nitrophenylphosphatase is an enzyme that catalyzes the hydrolysis of 4-nitrophenyl phosphate, producing 4-nitrophenol and phosphate. This enzyme is commonly used in laboratory assays to measure enzyme activity or to determine the presence of certain metals, such as aluminum and lead, which can inhibit its activity. The hydrolysis reaction results in the formation of yellow 4-nitrophenol, which can be easily measured spectrophotometrically at a wavelength of 405 nm. The activity of 4-nitrophenylphosphatase is often used as an indicator of the functional status of certain organelles, such as lysosomes, in biological systems.
Sodium-Potassium-Exchanging ATPase (also known as Na+/K+ ATPase) is a type of active transporter found in the cell membrane of many types of cells. It plays a crucial role in maintaining the electrochemical gradient and membrane potential of animal cells by pumping sodium ions (Na+) out of the cell and potassium ions (K+) into the cell, using energy derived from ATP hydrolysis.
This transporter is composed of two main subunits: a catalytic α-subunit that contains the binding sites for Na+, K+, and ATP, and a regulatory β-subunit that helps in the proper targeting and functioning of the pump. The Na+/K+ ATPase plays a critical role in various physiological processes, including nerve impulse transmission, muscle contraction, and kidney function.
In summary, Sodium-Potassium-Exchanging ATPase is an essential membrane protein that uses energy from ATP to transport sodium and potassium ions across the cell membrane, thereby maintaining ionic gradients and membrane potentials necessary for normal cellular function.
Duchenne Muscular Dystrophy (DMD) is a genetic disorder characterized by progressive muscle weakness and degeneration. It is caused by the absence of dystrophin, a protein that helps keep muscle cells intact. Without dystrophin, the muscle cells break down and are replaced with scar tissue, leading to loss of muscle function over time.
DMD primarily affects boys, as it is inherited in an X-linked recessive pattern, meaning that females who carry one affected X chromosome typically do not show symptoms but can pass the gene on to their offspring. Symptoms usually begin in early childhood and include difficulty with motor skills such as walking, running, and climbing stairs. Over time, the muscle weakness progresses and can lead to loss of ambulation, respiratory and cardiac complications, and ultimately, premature death.
Currently, there is no cure for DMD, but various treatments such as corticosteroids, physical therapy, and assisted ventilation can help manage symptoms and improve quality of life. Gene therapy approaches are also being investigated as potential treatments for this disorder.
Calcium is an essential mineral that is vital for various physiological processes in the human body. The medical definition of calcium is as follows:
Calcium (Ca2+) is a crucial cation and the most abundant mineral in the human body, with approximately 99% of it found in bones and teeth. It plays a vital role in maintaining structural integrity, nerve impulse transmission, muscle contraction, hormonal secretion, blood coagulation, and enzyme activation.
Calcium homeostasis is tightly regulated through the interplay of several hormones, including parathyroid hormone (PTH), calcitonin, and vitamin D. Dietary calcium intake, absorption, and excretion are also critical factors in maintaining optimal calcium levels in the body.
Hypocalcemia refers to low serum calcium levels, while hypercalcemia indicates high serum calcium levels. Both conditions can have detrimental effects on various organ systems and require medical intervention to correct.
Nitric Oxide Synthase Type I, also known as NOS1 or neuronal nitric oxide synthase (nNOS), is an enzyme that catalyzes the production of nitric oxide (NO) from L-arginine. It is primarily expressed in the nervous system, particularly in neurons, and plays a crucial role in the regulation of neurotransmission, synaptic plasticity, and cerebral blood flow. NOS1 is calcium-dependent and requires several cofactors for its activity, including NADPH, FAD, FMN, and calmodulin. It is involved in various physiological and pathological processes, such as learning and memory, seizure susceptibility, and neurodegenerative disorders.
Costameres are specialized structures found in muscle cells, specifically at the sarcolemma-sarcomere interface. The term "costamere" is derived from the Greek words "kosta," meaning coast or shore, and "meros," meaning part. These structures were first described by Dr. Seiji Ishikawa in 1981.
Costameres are composed of a network of proteins that connect the extracellular matrix to the contractile apparatus of muscle cells. They primarily consist of integrin complexes, vinculin, talin, and dystrophin-associated glycoprotein complex (DGC). Integrins, which are transmembrane receptors, connect the extracellular matrix to the cytoskeleton by interacting with intracellular proteins like talin and vinculin. The DGC, on the other hand, links the actin cytoskeleton to the sarcolemma, providing structural support and protection to muscle cells.
Costameres play a crucial role in maintaining the integrity of muscle fibers during contraction and force transmission. They also contribute to signaling pathways that regulate muscle cell growth, differentiation, and survival. Mutations or dysfunctions in costamere-associated proteins can lead to various muscular disorders, such as muscular dystrophies and myopathies.
The sarcoplasmic reticulum (SR) is a specialized type of smooth endoplasmic reticulum found in muscle cells, particularly in striated muscles such as skeletal and cardiac muscles. It is a complex network of tubules that surrounds the myofibrils, the contractile elements of the muscle fiber.
The primary function of the sarcoplasmic reticulum is to store calcium ions (Ca2+) and regulate their release during muscle contraction and uptake during muscle relaxation. The SR contains a high concentration of calcium-binding proteins, such as calsequestrin, which help to maintain this storage.
The release of calcium ions from the sarcoplasmic reticulum is triggered by an action potential that travels along the muscle fiber's sarcolemma and into the muscle fiber's interior (the sarcoplasm). This action potential causes the voltage-gated calcium channels in the SR membrane, known as ryanodine receptors, to open, releasing Ca2+ ions into the sarcoplasm.
The increased concentration of Ca2+ ions in the sarcoplasm triggers muscle contraction by binding to troponin, a protein associated with actin filaments, causing a conformational change that exposes the active sites on actin for myosin heads to bind and generate force.
After muscle contraction, the calcium ions must be actively transported back into the sarcoplasmic reticulum by Ca2+ ATPase pumps, also known as sarco(endo)plasmic reticulum calcium ATPases (SERCAs). This process helps to lower the concentration of Ca2+ in the sarcoplasm and allows the muscle fiber to relax.
Overall, the sarcoplasmic reticulum plays a crucial role in excitation-contraction coupling, the process by which action potentials trigger muscle contraction.
Freeze fracturing is not a medical term itself, but it is a technique used in the field of electron microscopy, which is a type of imaging commonly used in scientific research and medical fields to visualize structures at a very small scale, such as cells and cellular components.
In freeze fracturing, a sample is rapidly frozen to preserve its structure and then fractured or split along a plane of weakness, often along the membrane of a cell. The freshly exposed surface is then shadowed with a thin layer of metal, such as platinum or gold, to create a replica of the surface. This replica can then be examined using an electron microscope to reveal details about the structure and organization of the sample at the molecular level.
Freeze fracturing is particularly useful for studying membrane structures, such as lipid bilayers and protein complexes, because it allows researchers to visualize these structures in their native state, without the need for staining or other chemical treatments that can alter or damage the samples.
A sodium-calcium exchanger (NCX) is a type of ion transport protein found in the membranes of cells, including those of the heart and brain. It plays a crucial role in regulating intracellular calcium concentrations by facilitating the exchange of sodium ions for calcium ions across the cell membrane.
During each heartbeat, calcium ions enter the cardiac muscle cells to trigger contraction. After the contraction, the sodium-calcium exchanger helps remove excess calcium from the cell by exchanging it for sodium ions. This process is essential for maintaining normal calcium levels within the cell and allowing the heart muscle to relax between beats.
There are three main isoforms of the sodium-calcium exchanger (NCX1, NCX2, and NCX3) with different tissue distributions and functions. Dysfunction in sodium-calcium exchangers has been implicated in various pathological conditions such as heart failure, hypertension, and neurological disorders.
Caveolins are a group of proteins that are the main structural components of caveolae, which are small invaginations or "caves" found in the plasma membrane of many cell types. These proteins play important roles in various cellular processes such as endocytosis, cholesterol homeostasis, and signal transduction.
There are three main caveolin isoforms: caveolin-1, caveolin-2, and caveolin-3. Caveolin-1 is the most well-studied and is expressed in many cell types, while caveolin-2 and caveolin-3 have more restricted expression patterns. Caveolin-1 and caveolin-2 are co-expressed in many cells and can form hetero-oligomers, while caveolin-3 primarily forms homo-oligomers.
Caveolins have a number of functional domains that allow them to interact with various proteins and lipids. For example, the C-terminal domain of caveolin-1 contains a binding site for cholesterol, which helps to regulate the formation and stability of caveolae. Additionally, the N-terminal domain of caveolin-1 contains a binding site for various signaling proteins, allowing it to act as a scaffolding protein that organizes signaling complexes within caveolae.
Mutations in caveolin genes have been associated with several human diseases, including muscular dystrophy, cardiovascular disease, and cancer.
Wheat germ agglutinins (WGA) are proteins found in wheat germ that have the ability to bind to specific carbohydrate structures, such as N-acetylglucosamine and sialic acid, which are present on the surface of many cells in the human body. WGA is a type of lectin, a group of proteins that can agglutinate, or clump together, red blood cells and bind to specific sugars on cell membranes.
WGA has been studied for its potential effects on various biological processes, including inflammation, immune response, and gut barrier function. Some research suggests that WGA may interact with the gut epithelium and affect intestinal permeability, potentially contributing to the development of gastrointestinal symptoms in some individuals. However, more research is needed to fully understand the clinical significance of these findings.
It's worth noting that while WGA has been studied for its potential biological effects, it is not currently recognized as a major allergen or toxic component of wheat. However, some people may still choose to avoid foods containing WGA due to personal dietary preferences or sensitivities.
Sodium is an essential mineral and electrolyte that is necessary for human health. In a medical context, sodium is often discussed in terms of its concentration in the blood, as measured by serum sodium levels. The normal range for serum sodium is typically between 135 and 145 milliequivalents per liter (mEq/L).
Sodium plays a number of important roles in the body, including:
* Regulating fluid balance: Sodium helps to regulate the amount of water in and around your cells, which is important for maintaining normal blood pressure and preventing dehydration.
* Facilitating nerve impulse transmission: Sodium is involved in the generation and transmission of electrical signals in the nervous system, which is necessary for proper muscle function and coordination.
* Assisting with muscle contraction: Sodium helps to regulate muscle contractions by interacting with other minerals such as calcium and potassium.
Low sodium levels (hyponatremia) can cause symptoms such as confusion, seizures, and coma, while high sodium levels (hypernatremia) can lead to symptoms such as weakness, muscle cramps, and seizures. Both conditions require medical treatment to correct.
Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).
In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.
In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.
REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.
Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.
Plectin is a large cytolinker protein that plays a crucial role in the structural organization and stability of the cell. It has the ability to interact with various components of the cytoskeleton, including intermediate filaments, microtubules, and actin filaments, thereby providing a critical link between these structures. Plectin is widely expressed in many tissues and is involved in maintaining the integrity and functionality of cells under both physiological and pathological conditions. Mutations in the gene encoding plectin have been associated with several human diseases, including epidermolysis bullosa, muscular dystrophy, and neuropathies.
Myofibrils are the basic contractile units of muscle fibers, composed of highly organized arrays of thick and thin filaments. They are responsible for generating the force necessary for muscle contraction. The thick filaments are primarily made up of the protein myosin, while the thin filaments are mainly composed of actin. Myofibrils are surrounded by a membrane called the sarcolemma and are organized into repeating sections called sarcomeres, which are the functional units of muscle contraction.
Cardiac myocytes are the muscle cells that make up the heart muscle, also known as the myocardium. These specialized cells are responsible for contracting and relaxing in a coordinated manner to pump blood throughout the body. They differ from skeletal muscle cells in several ways, including their ability to generate their own electrical impulses, which allows the heart to function as an independent rhythmical pump. Cardiac myocytes contain sarcomeres, the contractile units of the muscle, and are connected to each other by intercalated discs that help coordinate contraction and ensure the synchronous beating of the heart.
I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.
If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.
The heart ventricles are the two lower chambers of the heart that receive blood from the atria and pump it to the lungs or the rest of the body. The right ventricle pumps deoxygenated blood to the lungs, while the left ventricle pumps oxygenated blood to the rest of the body. Both ventricles have thick, muscular walls to generate the pressure necessary to pump blood through the circulatory system.
Cytoskeletal proteins are a type of structural proteins that form the cytoskeleton, which is the internal framework of cells. The cytoskeleton provides shape, support, and structure to the cell, and plays important roles in cell division, intracellular transport, and maintenance of cell shape and integrity.
There are three main types of cytoskeletal proteins: actin filaments, intermediate filaments, and microtubules. Actin filaments are thin, rod-like structures that are involved in muscle contraction, cell motility, and cell division. Intermediate filaments are thicker than actin filaments and provide structural support to the cell. Microtubules are hollow tubes that are involved in intracellular transport, cell division, and maintenance of cell shape.
Cytoskeletal proteins are composed of different subunits that polymerize to form filamentous structures. These proteins can be dynamically assembled and disassembled, allowing cells to change their shape and move. Mutations in cytoskeletal proteins have been linked to various human diseases, including cancer, neurological disorders, and muscular dystrophies.
Aquaporin 4 (AQP4) is a water channel protein that is primarily found in the membranes of astrocytes, which are a type of glial cell in the central nervous system. AQP4 plays a crucial role in the regulation of water homeostasis and the clearance of excess fluid from the brain and spinal cord. It also facilitates the rapid movement of water across the blood-brain barrier and between astrocytes, which is important for maintaining proper neuronal function and protecting the brain from edema or swelling.
Mutations in the AQP4 gene can lead to various neurological disorders, such as neurodegenerative diseases and neuromyelitis optica spectrum disorder (NMOSD), a severe autoimmune condition that affects the optic nerves and spinal cord. In NMOSD, the immune system mistakenly attacks AQP4 proteins, causing inflammation, demyelination, and damage to the nervous tissue.
"Ligusticum" is a genus name in botany, which refers to a group of plants belonging to the carrot family (Apiaceae). There are several species within this genus, including "Ligusticum porteri" and "Ligusticum sinense," which have been used in traditional medicine.
In a medical context, "Ligusticum" is not commonly used as a standalone term but rather refers to the medicinal properties of specific species within this genus. For example, "Ligusticum porteri," also known as Osha or Porter's Lovage, has been traditionally used in Native American medicine for treating respiratory and digestive issues. Similarly, "Ligusticum sinense," or Chinese Lovage, is commonly used in Traditional Chinese Medicine (TCM) to treat various conditions such as cough, asthma, and menstrual disorders.
It's important to note that while some species of Ligusticum have been used in traditional medicine, there is limited scientific evidence to support their efficacy or safety. Therefore, it's recommended to consult with a healthcare professional before using any herbal remedies.
Bioinorganic chemistry is a subfield of chemical science that explores the interactions between metal ions and biological systems. This field combines principles from inorganic chemistry, biochemistry, and molecular biology to understand how metal ions contribute to various biological processes, including enzyme catalysis, signaling pathways, and metal homeostasis.
Bioinorganic chemists study the mechanisms of metal ion uptake, transport, storage, and elimination in living organisms. They also investigate the roles that metal ions play in diseases such as cancer, neurodegenerative disorders, and infectious diseases. By understanding these processes at a molecular level, researchers can develop new therapeutic strategies to target specific disease-related pathways or restore normal metal ion homeostasis.
Examples of bioinorganic chemistry research include the study of iron-sulfur clusters in enzymes, the design and development of metal-based drugs for cancer therapy, and the investigation of metal ion interactions with proteins involved in neurodegenerative disorders like Alzheimer's disease.
Calcium-transporting ATPases, also known as calcium pumps, are a type of enzyme that use the energy from ATP (adenosine triphosphate) hydrolysis to transport calcium ions across membranes against their concentration gradient. This process helps maintain low intracellular calcium concentrations and is essential for various cellular functions, including muscle contraction, neurotransmitter release, and gene expression.
There are two main types of calcium-transporting ATPases: the sarcoplasmic/endoplasmic reticulum Ca^2+^-ATPase (SERCA) and the plasma membrane Ca^2+^-ATPase (PMCA). SERCA is found in the sarcoplasmic reticulum of muscle cells and endoplasmic reticulum of other cell types, where it pumps calcium ions into these organelles to initiate muscle relaxation or signal transduction. PMCA, on the other hand, is located in the plasma membrane and extrudes calcium ions from the cell to maintain low cytosolic calcium concentrations.
Calcium-transporting ATPases play a crucial role in maintaining calcium homeostasis in cells and are important targets for drug development in various diseases, including heart failure, hypertension, and neurological disorders.
I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.
However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.
The Fluorescent Antibody Technique (FAT) is a type of immunofluorescence assay used in laboratory medicine and pathology for the detection and localization of specific antigens or antibodies in tissues, cells, or microorganisms. In this technique, a fluorescein-labeled antibody is used to selectively bind to the target antigen or antibody, forming an immune complex. When excited by light of a specific wavelength, the fluorescein label emits light at a longer wavelength, typically visualized as green fluorescence under a fluorescence microscope.
The FAT is widely used in diagnostic microbiology for the identification and characterization of various bacteria, viruses, fungi, and parasites. It has also been applied in the diagnosis of autoimmune diseases and certain cancers by detecting specific antibodies or antigens in patient samples. The main advantage of FAT is its high sensitivity and specificity, allowing for accurate detection and differentiation of various pathogens and disease markers. However, it requires specialized equipment and trained personnel to perform and interpret the results.
Vinculin is a protein found in many types of cells, including muscle and endothelial cells. It is primarily located at the sites of cell-cell and cell-matrix adhesions, where it plays important roles in cell adhesion, mechanotransduction, and cytoskeletal organization. Vinculin interacts with several other proteins, including actin, talin, and integrins, to form a complex network that helps regulate the connection between the extracellular matrix and the intracellular cytoskeleton. Mutations in the vinculin gene have been associated with certain inherited diseases, such as muscular dystrophy-cardiomyopathy syndrome.
Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:
1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction
Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:
1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.
Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).
Desmin is a type of intermediate filament protein that is primarily found in the cardiac and skeletal muscle cells, as well as in some types of smooth muscle cells. It is an important component of the cytoskeleton, which provides structural support to the cell and helps maintain its shape. Desmin plays a crucial role in maintaining the integrity of the sarcomere, which is the basic contractile unit of the muscle fiber. Mutations in the desmin gene can lead to various forms of muscular dystrophy and other inherited muscle disorders.
In medical terms, the heart is a muscular organ located in the thoracic cavity that functions as a pump to circulate blood throughout the body. It's responsible for delivering oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the rest of the body. The heart's rhythmic contractions and relaxations are regulated by a complex electrical conduction system.
Myocardial contraction refers to the rhythmic and forceful shortening of heart muscle cells (myocytes) in the myocardium, which is the muscular wall of the heart. This process is initiated by electrical signals generated by the sinoatrial node, causing a wave of depolarization that spreads throughout the heart.
During myocardial contraction, calcium ions flow into the myocytes, triggering the interaction between actin and myosin filaments, which are the contractile proteins in the muscle cells. This interaction causes the myofilaments to slide past each other, resulting in the shortening of the sarcomeres (the functional units of muscle contraction) and ultimately leading to the contraction of the heart muscle.
Myocardial contraction is essential for pumping blood throughout the body and maintaining adequate circulation to vital organs. Any impairment in myocardial contractility can lead to various cardiac disorders, such as heart failure, cardiomyopathy, and arrhythmias.
Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.
Glucose Transporter Type 4 (GLUT4) is a type of glucose transporter protein that plays a crucial role in regulating insulin-mediated glucose uptake into cells, particularly in muscle and fat tissues. GLUT4 is primarily located in intracellular vesicles within these cell types and moves to the plasma membrane upon stimulation by insulin or muscle contraction, facilitating the influx of glucose into the cell. Dysfunction in GLUT4 regulation has been implicated in various metabolic disorders, including type 2 diabetes and insulin resistance.
Cell fractionation is a laboratory technique used to separate different cellular components or organelles based on their size, density, and other physical properties. This process involves breaking open the cell (usually through homogenization), and then separating the various components using various methods such as centrifugation, filtration, and ultracentrifugation.
The resulting fractions can include the cytoplasm, mitochondria, nuclei, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and other organelles. Each fraction can then be analyzed separately to study the biochemical and functional properties of the individual components.
Cell fractionation is a valuable tool in cell biology research, allowing scientists to study the structure, function, and interactions of various cellular components in a more detailed and precise manner.
Muscular diseases, also known as myopathies, refer to a group of conditions that affect the functionality and health of muscle tissue. These diseases can be inherited or acquired and may result from inflammation, infection, injury, or degenerative processes. They can cause symptoms such as weakness, stiffness, cramping, spasms, wasting, and loss of muscle function.
Examples of muscular diseases include:
1. Duchenne Muscular Dystrophy (DMD): A genetic disorder that results in progressive muscle weakness and degeneration due to a lack of dystrophin protein.
2. Myasthenia Gravis: An autoimmune disease that causes muscle weakness and fatigue, typically affecting the eyes and face, throat, and limbs.
3. Inclusion Body Myositis (IBM): A progressive muscle disorder characterized by muscle inflammation and wasting, typically affecting older adults.
4. Polymyositis: An inflammatory myopathy that causes muscle weakness and inflammation throughout the body.
5. Metabolic Myopathies: A group of inherited disorders that affect muscle metabolism, leading to exercise intolerance, muscle weakness, and other symptoms.
6. Muscular Dystonias: Involuntary muscle contractions and spasms that can cause abnormal postures or movements.
It is important to note that muscular diseases can have a significant impact on an individual's quality of life, mobility, and overall health. Proper diagnosis and treatment are crucial for managing symptoms and improving outcomes.
Fast-twitch muscle fibers, also known as type II fibers, are a type of skeletal muscle fiber that are characterized by their rapid contraction and relaxation rates. These fibers have a larger diameter and contain a higher concentration of glycogen, which serves as a quick source of energy for muscle contractions. Fast-twitch fibers are further divided into two subcategories: type IIa and type IIb (or type IIx). Type IIa fibers have a moderate amount of mitochondria and can utilize both aerobic and anaerobic metabolic pathways, making them fatigue-resistant. Type IIb fibers, on the other hand, have fewer mitochondria and primarily use anaerobic metabolism, leading to faster fatigue. Fast-twitch fibers are typically used in activities that require quick, powerful movements such as sprinting or weightlifting.
I'm sorry for any confusion, but "Receptors, Albumin" is not a standard medical term or concept.
Albumin is a type of protein produced by the liver that circulates in blood plasma. It plays several important roles, such as maintaining oncotic pressure (helping to keep fluid in the blood vessels), transporting various substances like hormones, drugs, and fatty acids, and acting as an antioxidant.
Receptors, on the other hand, are proteins on the surface of cells that interact with specific molecules (like hormones, neurotransmitters, or drugs) to trigger a response within the cell. Different receptors respond to different molecules, and there are many types of receptors in the human body.
If you meant something else or need information on a related topic, please provide more context or clarify your question.
The neuromuscular junction (NMJ) is the specialized synapse or chemical communication point, where the motor neuron's nerve terminal (presynaptic element) meets the muscle fiber's motor end plate (postsynaptic element). This junction plays a crucial role in controlling muscle contraction and relaxation.
At the NMJ, the neurotransmitter acetylcholine is released from the presynaptic nerve terminal into the synaptic cleft, following an action potential. Acetylcholine then binds to nicotinic acetylcholine receptors on the postsynaptic membrane of the muscle fiber, leading to the generation of an end-plate potential. If sufficient end-plate potentials are generated and summate, they will trigger an action potential in the muscle fiber, ultimately causing muscle contraction.
Dysfunction at the neuromuscular junction can result in various neuromuscular disorders, such as myasthenia gravis, where autoantibodies attack acetylcholine receptors, leading to muscle weakness and fatigue.
Saxitoxin (STX) is a potent neurotoxin that inhibits the sodium channels in nerve cells, leading to paralysis and potentially death. It is produced by certain species of marine dinoflagellates and cyanobacteria, and can accumulate in shellfish that feed on these organisms. Saxitoxin poisoning, also known as paralytic shellfish poisoning (PSP), is a serious medical condition that can cause symptoms such as numbness, tingling, and paralysis of the mouth and extremities, as well as respiratory failure and death in severe cases. It is important to note that saxitoxin is not used as a therapeutic agent in medicine and is considered a harmful substance.
Spectrin is a type of cytoskeletal protein that is responsible for providing structural support and maintaining the shape of red blood cells (erythrocytes). It is a key component of the erythrocyte membrane skeleton, which provides flexibility and resilience to these cells, allowing them to deform and change shape as they pass through narrow capillaries. Spectrin forms a network of fibers just beneath the cell membrane, along with other proteins such as actin, band 4.1, and band 3. Mutations in spectrin genes can lead to various blood disorders, including hereditary spherocytosis and hemolytic anemia.
Ouabain is defined as a cardiac glycoside, a type of steroid, that is found in the seeds and roots of certain plants native to Africa. It is used in medicine as a digitalis-like agent to increase the force of heart contractions and slow the heart rate, particularly in the treatment of congestive heart failure and atrial fibrillation. Ouabain functions by inhibiting the sodium-potassium pump (Na+/K+-ATPase) in the cell membrane, leading to an increase in intracellular sodium and calcium ions, which ultimately enhances cardiac muscle contractility. It is also known as g-strophanthin or ouabaine.
Dihydroalprenolol is a non-selective beta blocker drug, which means it blocks both beta-1 and beta-2 receptors. Beta blockers are medications that reduce the effects of epinephrine (adrenaline) in the body, thereby slowing down the heart rate, reducing blood pressure, and decreasing the force of heart contractions.
Dihydroalprenolol is primarily used to treat hypertension (high blood pressure), angina pectoris (chest pain due to reduced blood flow to the heart muscle), and certain types of arrhythmias (irregular heart rhythms). It may also be used for other indications, such as preventing migraines or reducing anxiety before surgery.
Like other beta blockers, dihydroalprenolol works by blocking the action of epinephrine on beta receptors in the heart and blood vessels, leading to decreased heart rate, reduced force of heart contractions, and dilated blood vessels. This results in lower blood pressure and improved blood flow to the heart muscle.
It is important to note that dihydroalprenolol may have side effects, such as fatigue, dizziness, and gastrointestinal symptoms, and it should be used under the guidance of a healthcare professional. Additionally, sudden discontinuation of beta blockers can lead to rebound hypertension or other adverse effects, so it is essential to taper off the medication gradually under medical supervision.
Myotonia is a condition characterized by the delayed relaxation of a muscle after voluntary contraction or electrical stimulation, resulting in stiffness or difficulty with relaxing the muscles. It's often associated with certain neuromuscular disorders such as myotonic dystrophy and myotonia congenita. The prolonged muscle contraction can cause stiffness, especially after periods of rest, and may improve with repeated contractions (warm-up phenomenon).
A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.
Nitrendipine is an antihypertensive drug, which belongs to the class of calcium channel blockers. It works by relaxing and widening the blood vessels, making it easier for the heart to pump blood and reducing the workload on the cardiovascular system. This helps to lower high blood pressure (hypertension) and improve overall cardiovascular health. Nitrendipine is available in oral tablet form and is typically prescribed by a healthcare professional for the treatment of hypertension.
It's important to note that this definition is intended to be a general overview of the medical use and properties of Nitrendipine, and it should not be used as a substitute for professional medical advice or treatment. Always consult with a qualified healthcare provider for information regarding any specific medical condition or treatment.
Annexin A6 is a protein that belongs to the annexin family, which are calcium-dependent phospholipid-binding proteins. Annexin A6 is involved in various cellular processes such as exocytosis, endocytosis, and membrane trafficking. It has been shown to play a role in regulating ion channels, modulating the actin cytoskeleton, and interacting with other proteins to form multimolecular complexes. Annexin A6 is expressed in various tissues, including the heart, lung, kidney, and pancreas. Mutations in the ANXA6 gene have been associated with certain diseases, such as kidney stones and cataracts.
Calcium-binding proteins (CaBPs) are a diverse group of proteins that have the ability to bind calcium ions (Ca^2+^) with high affinity and specificity. They play crucial roles in various cellular processes, including signal transduction, muscle contraction, neurotransmitter release, and protection against oxidative stress.
The binding of calcium ions to these proteins induces conformational changes that can either activate or inhibit their functions. Some well-known CaBPs include calmodulin, troponin C, S100 proteins, and parvalbumins. These proteins are essential for maintaining calcium homeostasis within cells and for mediating the effects of calcium as a second messenger in various cellular signaling pathways.
Subcellular fractions refer to the separation and collection of specific parts or components of a cell, including organelles, membranes, and other structures, through various laboratory techniques such as centrifugation and ultracentrifugation. These fractions can be used in further biochemical and molecular analyses to study the structure, function, and interactions of individual cellular components. Examples of subcellular fractions include nuclear extracts, mitochondrial fractions, microsomal fractions (membrane vesicles), and cytosolic fractions (cytoplasmic extracts).
I could not find a medical definition specifically for "Cocos." However, Cocos is a geographical name that may refer to:
* The Cocos (Keeling) Islands, an Australian territory in the Indian Ocean.
* Cocos nucifera, the scientific name for the coconut palm tree.
There are some medical conditions related to the consumption of coconuts or exposure to the coconut palm tree, such as allergies to coconut products, but there is no specific medical term "Cocos."
The Dystrophin-Associated Protein Complex (DAPC) is a group of proteins found in muscle cells that work together to provide structural stability and support to the cell membrane, also known as the sarcolemma. The complex is named for its association with dystrophin, a protein that is deficient or mutated in individuals with Duchenne and Becker muscular dystrophy.
The DAPC includes several proteins, such as dystroglycan, sarcoglycans, syntrophins, and dystrobrevin, among others. These proteins form a network that connects the intracellular cytoskeleton to the extracellular matrix, helping to maintain the integrity of the muscle cell during contraction and relaxation.
Mutations in genes encoding for these DAPC proteins can lead to various forms of muscular dystrophy, including Duchenne and Becker muscular dystrophy, as well as limb-girdle muscular dystrophy and congenital muscular dystrophy. Understanding the structure and function of the DAPC is crucial for developing potential therapies to treat these genetic disorders.
Immunohistochemistry (IHC) is a technique used in pathology and laboratory medicine to identify specific proteins or antigens in tissue sections. It combines the principles of immunology and histology to detect the presence and location of these target molecules within cells and tissues. This technique utilizes antibodies that are specific to the protein or antigen of interest, which are then tagged with a detection system such as a chromogen or fluorophore. The stained tissue sections can be examined under a microscope, allowing for the visualization and analysis of the distribution and expression patterns of the target molecule in the context of the tissue architecture. Immunohistochemistry is widely used in diagnostic pathology to help identify various diseases, including cancer, infectious diseases, and immune-mediated disorders.
Sarcolemma
SGCB
SLMAP
Muscle cell
Skeletal muscle
Striated muscle tissue
Dysferlin
Endomysium
Costamere
Neuromuscular-blocking drug
Cell membrane
PARVB
TMEM43
Dystrobrevin alpha
Nicorandil
Myogenesis
Action potential
Cardiac excitation-contraction coupling
Cardiac physiology
Exertional rhabdomyolysis
Voltage-sensitive dye
Syntrophin, alpha 1
NOS1
Sarcomere
Rigor mortis
ANNINE-6plus
Utrophin
Torkel Weis-Fogh
Calcium sparks
Actin, cytoplasmic 2
Sarcolemma - Wikipedia
Dystrobrevin deficiency at the sarcolemma of patients with muscular dystrophy. - Oxford Neuroscience
KCNB1 potassium voltage-gated channel subfamily B member 1 [Homo sapiens (human)] - Gene - NCBI
Atp1b1 ATPase, Na+/K+ transporting, beta 1 polypeptide [Mus musculus (house mouse)] - Gene - NCBI
Frontiers | Skeletal Muscles Do Not Undergo Apoptosis During Either Atrophy or Programmed Cell Death-Revisiting the Myonuclear...
Exercise Physiology: Overview, Basic Concepts -- Sex Differences, Musculoskeletal System
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Group A Streptococcal (GAS) Infections: Background, Pathophysiology, Etiology
Cardiogenetics | Free Full-Text | Sarcomeric versus Non-Sarcomeric HCM
Histology of Skeletal Muscle : Wheeless' Textbook of Orthopaedics
Publications - Professor Thomas Brand
TCDB » SEARCH
PPT - Muscle PowerPoint Presentation, free download - ID:5659528
Symptomatic dysferlin gene mutation carriers: characterization of two cases
DMD Gene Therapy Safe, Effective at 4 Years
Chapter 6 Flashcards by Justin Perry | Brainscape
Human CD97 ELISA Kit (ab213763) | Abcam
Cardiac muscle - wikidoc
Actin and myosin | PPT
Non-Cholinergic Signaling Pathways at Vertebrate Neuromuscular Junctions | IntechOpen
Mark H. Ellisman - Publications
RYR1 mutations in UK central core disease patients: more than just the C-terminal transmembrane region of the RYR1 gene |...
Physical Medicine and Rehabilitation for Limb-Girdle Muscular Dystrophy: Practice Essentials, Pathophysiology, Epidemiology
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Frank E. Stockdale's Profile | Stanford Profiles
Metabolites | April 2021 - Browse Articles
Headlines 2018
Muscular system Cheat Sheet by jonahenry - Download free from Cheatography - Cheatography.com: Cheat Sheets For Every Occasion
UBIRA ETheses - Functions of Caveolin-1 and Caveolin-3 in muscular dystrophy
Sarcoplasmic reticulum4
- CD97 is expressed at the sarcoplasmic reticulum and the peripheral sarcolemma in skeletal muscle. (abcam.com)
- The role of the sarcolemma and the sarcoplasmic reticulum in the altered calcium dynamics was also examined. (cdc.gov)
- The effect appears mediated via actions of calcium fluxes at the sarcolemma and sarcoplasmic reticulum. (cdc.gov)
- As a result, the sarcolemma becomes more permeable to sodium ions, resulting in more action potentials that spread along its external surface and into the interior of the muscle fiber through transverse or T-tubules, which triggers the release of calcium ions from the sarcoplasmic reticulum into the myofibrils. (jove.com)
Plasma membrane4
- The sarcolemma generally maintains the same function in muscle cells as the plasma membrane does in other eukaryote cells. (wikipedia.org)
- Each fiber is covered by a sarcolemma (plasma membrane). (medscape.com)
- each fiber has a limiting plasma membrane, the sarcolemma. (wheelessonline.com)
- Scaffolding proteins play important roles in supporting the plasma membrane (sarcolemma) of muscle cells. (cea.fr)
Dystrophin5
- Often referred to as a molecular "shock absorber," dystrophin stabilizes the sarcolemma during muscle contractions to prevent degeneration. (medscape.com)
- Among them, dystrophin strengthens the sarcolemma through protein-lipid interactions, and its absence due to gene mutations leads to the severe Duchenne muscular dystrophy. (cea.fr)
- The skeletal muscles of DMD have disrupted dystrophin-glycoprotein complex (DGC) and impaired sarcolemma integrity. (bham.ac.uk)
- Duchenne muscular dystrophy (DMD) is caused by the lack of dystrophin protein at the sarcolemma. (neurology-jp.org)
- Dystrophin gene is the largest human gene with 79 exons, codes for protein dystrophin required for stabilisation of protein complex at sarcolemma, the abnormal DMD gene is on X chromosome at Xp21 locus. (who.int)
Skeletal muscle1
- Skeletal muscle consists of 2 major components: the sarcolemma and the sarcomeres. (medscape.com)
Membrane2
- We conclude that the sarcolemma membrane anchoring that occurs during the contraction/elongation process of muscles could be ensured by this coiled-coil opening. (cea.fr)
- These neurotransmitters diffuse across the synapse and bind to specific receptor sites on the sarcolemma (cell membrane of the muscle fiber). (wikidoc.org)
Fibers1
- At each end of the muscle fiber, the surface layer of the sarcolemma fuses with a tendon fiber, and the tendon fibers, in turn, collect into bundles to form the muscle tendons that adhere to bones. (wikipedia.org)
Synaptic cleft1
- he highly folded sarcolemma that faces the synaptic cleft. (freezingblue.com)
Receptors3
- Change in the voltage of the sarcolemma causes the dihydropyridine receptors to open and allows an initial calcium flow to the sarcoplasm. (wikidoc.org)
- When enough receptors are stimulated, an action potential is generated and the permeability of the sarcolemma is altered. (wikidoc.org)
- Binding of acetylcholine to its receptors on the sarcolemma allows entry of sodium ions into the cell and triggers an action potential in the muscle cell. (jove.com)
Sarcoplasm1
- A special feature of the sarcolemma is that it invaginates into the sarcoplasm of the muscle cell, forming membranous tubules radially and longitudinally within the fiber called T-tubules or transverse tubules. (wikipedia.org)
Transverse1
- Transverse tubules (T tubules), which are extensions of the sarcolemma that penetrate cells, transmit electrical impulses from the sarcolemma inward, so electrical impulses penetrate deeply into the cell. (medscape.com)
Fiber1
- EN)do-mysium- connective tissue that covers the muscle fiber. (cheatography.com)
Proteins1
- The Popeye domain containing (POPDC) genes encode sarcolemma-localized cAMP effector proteins. (imperial.ac.uk)
Smooth1
- In the situation when one factor results in high blood pressure, the usual malfunction of ion pumps on sarcolemma membranes of smooth muscle cells is observed (Bakris, 2021). (custom-essay.org)
Sarcoplasmic2
Skeletal7
- Anti-dystrobrevin antibodies stain the sarcolemma in normal skeletal muscle indicating that dystrobrevin co-localises with dystrophin and the dystrophin-associated protein complex. (ox.ac.uk)
- Overall, our current and previous findings suggest that SSPN overexpression in DMD mouse models positively affects skeletal, pulmonary, and cardiac performance by addressing the stability of proteins at the sarcolemma that protect the heart from injury, supporting SSPN and membrane stabilization as a therapeutic target for DMD. (jci.org)
- Rhabdomyolysis is severe and acute skeletal muscle damage resulting in sarcolemma disruption. (medscimonit.com)
- Using transmission electron microscopy, two distinct subcellular pools of lipid droplets can be observed in skeletal muscle - one beneath the sarcolemma and the o. (researchgate.net)
- In the skeletal muscle, CIB2 co-localizes with the integrin alpha7B subunit at the sarcolemma and at the neuromuscular and myotendinous junctions. (prospecbio.com)
- Necrosis of the brain involving the cerebellum and/or hippocampus, degeneration and regeneration of the renal tubule epithelium, and degeneration and sarcolemma nuclear hyperplasia of the tongue and skeletal muscles occurred in most male and female 50,000 ppm rats. (nih.gov)
- From NCBI Gene: The protein encoded by this gene belongs to the ferlin family and is a skeletal muscle protein found associated with the sarcolemma. (nih.gov)
Cardiac3
- We demonstrate that SSPN ameliorated more advanced cardiac disease in the context of diminished sarcolemma expression of utrophin and β1D integrin, which mitigate disease severity, and partially restored responsiveness to β-adrenergic stimulation. (jci.org)
- 13. Prostaglandin E receptors in cardiac sarcolemma. (nih.gov)
- Phospholipase Cbeta1b associates with a Shank3 complex at the cardiac sarcolemma. (curehunter.com)
Depolarization1
- Here, in single-voltage clamped smooth muscle cells, sarcolemma depolarization generated uniform increases in [Ca2+]c throughout the cell entirely by Ca2+ influx. (strath.ac.uk)
Extracellular matrix1
- In addition, the microtraumas which are exercise-induced are dependent on the load components and include disruption of the extracellular matrix and basal lamina of the sarcolemma. (hindawi.com)
Deficiency1
- Dystrobrevin deficiency at the sarcolemma of patients with muscular dystrophy. (ox.ac.uk)
Damage1
- A lack of normal dysferlin leads to a reduced ability to repair damage done to the sarcolemma of muscle fibers. (medlineplus.gov)
Form1
- At each end of the muscle fiber, the surface layer of the sarcolemma fuses with a tendon fiber, and the tendon fibers, in turn, collect into bundles to form the muscle tendons that adhere to bones. (wikipedia.org)