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L-type Calcium Channel
The L-type calcium channel (also known as the dihydropyridine channel, or DHP channel) is part of the high-voltage activated family of voltage-dependent calcium channel. "L" stands for long-lasting referring to the length of activation. This channel has four isoforms: Cav1.1, Cav1.2, Cav1.3, and Cav1.4. L-type calcium channels are responsible for the excitation- contraction coupling of skeletal, smooth, cardiac muscle, and for aldosterone secretion in endocrine cells of the adrenal cortex. They are also found in neurons, and with the help of L-type calcium channels in endocrine cells, they regulate neurohormones and neurotransmitters. They have also been seen to play a role in gene expression, mRNA stability, neuronal survival, ischemic-induced axonal injury, synaptic efficacy, and both activation and deactivation of other ion channels. In cardiac myocytes, the L-type calcium channel passes inward Ca2+ current (ICaL) and triggers calcium release from the sarcoplasmic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L-type D-subtype CaV1
L-type or type-l or ''variation'', may refer to: L-type * L-type asteroid * L-type star * L-type lectin domain * L-type calcium channel * L-type ligand * Japanese L type submarine * L type carriage, rail car * MG L-type, an automobile * Renault L-Type engine Type-L * Type L socket, an AC power outlet * Zeppelin-Staaken Type "L", an airplane * Morane Saulnier Type L, an airplane * R.E.P. Type L Parasol, an airplane * Handley Page Type L, an airplane * Blackburn Type L, an airplane * Caudron Type L, an airplane * Thulin Type L, an airplane * Japanese Type L submarine * Soviet Type L submarine * Type L grenade See also * * * * * Type 1 (other) * Type (other) Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ... * L (other) * L class (disambiguatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiarrhythmics
Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a class of drugs that are used to suppress abnormally fast rhythms (tachycardias), such as atrial fibrillation, supraventricular tachycardia and ventricular tachycardia. Many attempts have been made to classify antiarrhythmic agents. Many of the antiarrhythmic agents have multiple modes of action, which makes any classification imprecise. Action potential The cardiac myocyte has two general types of action potentials: conduction system and working myocardium. The action potential is divided into 5 phases and shown in the diagram. The sharp rise in voltage ("0") corresponds to the influx of sodium ions, whereas the two decays ("1" and "3", respectively) correspond to the sodium-channel inactivation and the repolarizing efflux of potassium ions. The characteristic plateau ("2") results from the opening of voltage-sensitive calcium channels. Each phase utilizes different channels and it is useful to compar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage-gated Ion Channel
Voltage-gated ion channels are a class of transmembrane proteins that form ion channels that are activated by changes in a Cell (biology), cell's electrical membrane potential near the channel. The membrane potential alters the conformation of the channel proteins, regulating their opening and closing. Cell membranes are generally impermeable to ions, thus they must diffuse through the membrane through transmembrane protein channels. Voltage-gated ion channels have a crucial role in excitable cells such as neuronal and muscle tissues, allowing a rapid and co-ordinated depolarization in response to triggering Voltage drop, voltage change. Found along the axon and at the synapse, voltage-gated ion channels directionally propagate electrical signals. Voltage-gated ion-channels are usually ion-specific, and channels specific to Sodium channel#Voltage-gated, sodium (Na+), Voltage-gated potassium channel, potassium (K+), Voltage-dependent calcium channel, calcium (Ca2+), and Chloride ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Helix
An alpha helix (or α-helix) is a sequence of amino acids in a protein that are twisted into a coil (a helix). The alpha helix is the most common structural arrangement in the Protein secondary structure, secondary structure of proteins. It is also the most extreme type of local structure, and it is the local structure that is most easily predicted from a sequence of amino acids. The alpha helix has a right-handed helix conformation in which every backbone amino, N−H group hydrogen bonds to the backbone carbonyl, C=O group of the amino acid that is four residue (biochemistry), residues earlier in the protein sequence. Other names The alpha helix is also commonly called a: * Pauling–Corey–Branson α-helix (from the names of three scientists who described its structure) * 3.613-helix because there are 3.6 amino acids in one ring, with 13 atoms being involved in the ring formed by the hydrogen bond (starting with amidic hydrogen and ending with carbonyl oxygen) Discovery ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmembrane Protein
A transmembrane protein is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them ( beta-barrels) can be also extracted using denaturing agents. The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot. Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-pass membrane proteins, or as multipass membrane proteins. Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-type Calcium Channel
N-type calcium channels, also called Cav2.2 channels, are voltage gated calcium channels that are localized primarily on the nerve terminals and dendrites as well as neuroendocrine cells. The calcium N-channel consists of several subunits: the primary subunit α1B and the auxiliary subunits α2δ and β. The α1B subunit forms the pore through which the calcium enters and helps to determine most of the channel's properties. These channels play an important role in the neurotransmission during development. In the adult nervous system, N-type calcium channels are critically involved in the release of neurotransmitters, and in pain pathways. N-type calcium channels are the target of ziconotide, the drug prescribed to relieve intractable pain, intractable cancer pain. There are many known N-type calcium channel blockers that function to inhibit channel activity, although the most notable blockers are Conotoxin, ω-conotoxins. Structure N-type calcium channels are categorized as high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P-type Calcium Channel
The P-type calcium channel is a type of voltage-dependent calcium channel. Similar to many other high-voltage-gated calcium channels, the α1 subunit determines most of the channel's properties. The 'P' signifies cerebellar Purkinje cells, referring to the channel's initial site of discovery. P-type calcium channels play a similar role to the N-type calcium channel in neurotransmitter release at the presynaptic terminal and in neuronal integration in many neuronal types. History The calcium channel experiments that led to the discovery of P-type calcium channels were initially completed by Llinás and Sugimori in 1980. P type calcium channels were named in 1989 because they were discovered within mammalian Purkinje neurons. They were able to use an ''in vitro'' preparation to examine the ionic currents that account for Purkinje cells' electrophysiological properties. They found that there are calcium dependent action potentials which rise slowly and fall quickly then undergo hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydropyridine
1,4-Dihydropyridine (DHP) is an organic compound with the formula CH2(CH=CH)2NH. The parent compound is uncommon, but derivatives of 1,4-dihydropyridine are important commercially and biologically. The pervasive cofactors NADH and NADPH are derivatives of 1,4-dihydropyridine. Dihydropyridine calcium channel blockers are a class of L-type calcium channel blockers used in the treatment of hypertension. 1,2-Dihydropyridines are also known. Properties and reactions A recurring feature of 1,4-dihydropyridines is the presence of substituents at the 2- and 6-positions. Dihydropyridines are enamines, which otherwise tend to tautomerize or hydrolyze. The dominant reaction of dihydropyridines is their ease of oxidation. In the case of dihydropyridines with hydrogen as the substituent on nitrogen, oxidation yields pyridines: :CH2(CH=CR)2NH → C5H3R2N + H2 The naturally-occurring dihydropyridines NADH and NADPH contain N-alkyl groups. Therefore, their oxidation does not yield pyridi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-tubules
T-tubules (transverse tubules) are extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells. With membranes that contain large concentrations of ion channels, transporters, and pumps, T-tubules permit rapid transmission of the action potential into the cell, and also play an important role in regulating cellular calcium concentration. Through these mechanisms, T-tubules allow heart muscle cells to contract more forcefully by synchronising calcium release from the sarcoplasmic reticulum throughout the cell. T-tubule structure and function are affected beat-by-beat by cardiomyocyte contraction, as well as by diseases, potentially contributing to heart failure and arrhythmias. Although these structures were first seen in 1897, research into T-tubule biology is ongoing. Structure T-tubules are tubules formed from the same phospholipid bilayer as the surface membrane or sarcolemma of skeletal or cardiac muscle cells. They connect directly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nifedipine
Nifedipine ( ), sold under the brand name Procardia among others, is a calcium channel blocker medication used to manage angina, high blood pressure, Raynaud's phenomenon, and premature labor. It is one of the treatments of choice for Prinzmetal angina. It may be used to treat severe high blood pressure in pregnancy. Its use in preterm labor may allow more time for steroids to improve the baby's lung function and provide time for transfer of the mother to a well qualified medical facility before delivery. It is a calcium channel blocker of the dihydropyridine type. Nifedipine is taken by mouth and comes in fast- and slow-release formulations. Common side effects include lightheadedness, headache, feeling tired, leg swelling, cough, and shortness of breath. Serious side effects may include low blood pressure and heart failure. Nifedipine is considered safe in pregnancy and breastfeeding. Nifedipine was patented in 1967, and approved for use in the United States in 1981. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydropyridines
1,4-Dihydropyridine (DHP) is an organic compound with the formula CH2(CH=CH)2NH. The parent compound is uncommon, but derivatives of 1,4-dihydropyridine are important commercially and biologically. The pervasive cofactors NADH and NADPH are derivatives of 1,4-dihydropyridine. Dihydropyridine calcium channel blockers are a class of L-type calcium channel blockers used in the treatment of hypertension. 1,2-Dihydropyridines are also known. Properties and reactions A recurring feature of 1,4-dihydropyridines is the presence of substituents at the 2- and 6-positions. Dihydropyridines are enamines, which otherwise tend to tautomerize or hydrolyze. The dominant reaction of dihydropyridines is their ease of oxidation. In the case of dihydropyridines with hydrogen as the substituent on nitrogen, oxidation yields pyridines: :CH2(CH=CR)2NH → C5H3R2N + H2 The naturally-occurring dihydropyridines NADH and NADPH contain N-alkyl groups. Therefore, their oxidation does not yield pyrid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verapamil
Verapamil, sold under various trade names, is a calcium channel blocker medication used for the treatment of high blood pressure, angina (chest pain from not enough blood flow to the heart), and supraventricular tachycardia. It may also be used for the prevention of migraines and cluster headaches. It is given by mouth or by injection into a vein. Common side effects include headache, low blood pressure, nausea, and constipation. Other side effects include allergic reactions and muscle pains. It is not recommended in people with a slow heart rate or heart failure. It is believed to cause problems for the fetus if used during pregnancy. It is in the non–dihydropyridine calcium channel blocker family of medications. Verapamil was approved for medical use in the United States in 1981. It is on the World Health Organization's List of Essential Medicines. Verapamil is available as a generic medication. Long acting formulations exist. In 2022, it was the 188th most commonly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
