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Calcicludine
Calcicludine (CaC) is a protein toxin from the venom of the green mamba that inhibits high-voltage-activated calcium channels, especially L-type calcium channels. Sources Calcicludine is a toxin in the venom of the green mamba ''(Dendroaspis angusticeps)''. Chemistry Calcicludine is a 60-amino acid polypeptide with six cysteines forming three disulfide bridges. Calcicludine structurally resembles dendrotoxin, but works differently, since even at high concentrations, calcicludine has no effect on dendrotoxin-sensitive potassium channels in chicken and rat neurons. Target Calcicludine is a blocker of high-voltage-activated calcium channels (L-, N- and P-type channels). It has highest affinity to the L-type calcium channel ( IC50 = 88nM . However, sensitivity of the drug on the channel depends on the species and the tissue. For example, the IC50 for block of L-type calcium channels on a cerebellar granule cell is 0.2 nM, but the IC50 of the block of rat peripheral DRG ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Green Mamba
The eastern green mamba (''Dendroaspis angusticeps'') is a highly venomous snake species of the mamba genus ''Dendroaspis'' native to the coastal regions of southern East Africa. Described by Scottish surgeon and zoologist Andrew Smith in 1849, it has a slender build with a bright green back and green-yellow ventral scales. Adult females average around in length, and males are slightly smaller. A shy and elusive species, the eastern green mamba is rarely seen. This elusiveness is usually attributed to its arboreal habitat and green colouration, which acts as camouflage in its natural environment. It has also been observed to use ambush predation, like many vipers, contrary to the active foraging style typical of other elapid snakes. It preys on birds, eggs, bats, and rodents such as mice, rats, and gerbils. Its venom consists of both neurotoxins and cardiotoxins. Symptoms of envenomation include swelling of the injection site, dizziness, and nausea, accompanied by difficult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendroaspis Angusticeps
The eastern green mamba (''Dendroaspis angusticeps'') is a highly venomous snake species of the mamba genus ''Dendroaspis'' native to the coastal regions of southern East Africa. Described by Scottish surgeon and zoologist Andrew Smith in 1849, it has a slender build with a bright green back and green-yellow ventral scales. Adult females average around in length, and males are slightly smaller. A shy and elusive species, the eastern green mamba is rarely seen. This elusiveness is usually attributed to its arboreal habitat and green colouration, which acts as camouflage in its natural environment. It has also been observed to use ambush predation, like many vipers, contrary to the active foraging style typical of other elapid snakes. It preys on birds, eggs, bats, and rodents such as mice, rats, and gerbils. Its venom consists of both neurotoxins and cardiotoxins. Symptoms of envenomation include swelling of the injection site, dizziness, and nausea, accompanied by difficul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849–1919) and is derived from the word toxic. Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to potentially fatal even at extremely low doses (such as botulinum toxin). Toxins are largely secondary metabolites, which are organic compounds that are not directly involved in an organism's growth, development, or reproduction, instead often aiding it in matters of defense. Terminology Toxins are often distinguished from other chemical agents strictly based on their biological origin. Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IC50
The half maximal inhibitory concentration (IC50) is a measure of the potency of a substance in inhibiting a specific biological or biochemical function. IC50 is a quantitative measure that indicates how much of a particular inhibitory substance (e.g. drug) is needed to inhibit, ''in vitro'', a given biological process or biological component by 50%. The biological component could be an enzyme, cell, cell receptor or microorganism. IC50 values are typically expressed as molar concentration. IC50 is commonly used as a measure of antagonist drug potency in pharmacological research. IC50 is comparable to other measures of potency, such as EC50 for excitatory drugs. EC50 represents the dose or plasma concentration required for obtaining 50% of a maximum effect ''in vivo''. IC50 can be determined with functional assays or with competition binding assays. Sometimes, IC50 values are converted to the pIC50 scale. :\ce = -\log_ \ce Due to the minus sign, higher values of pIC50 indica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxins
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nervous tissue.Olney 2002 The term can also be used to classify endogenous compounds, which, when abnormally contacted, can prove neurologically toxic. Though neurotoxins are often neurologically destructive, their ability to specifically target neural components is important in the study of nervous systems. Common examples of neurotoxins include lead, ethanol (drinking alcohol), glutamate,Choi 1987 nitric oxide, botulinum toxin (e.g. Botox), tetanus toxin,Simpson 1986 and tetrodotoxin. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Neurotoxins inhibit neuron control over ion concentrations across the cell membrane, or c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendroaspis
Mambas are fast moving highly venomous snakes of the genus ''Dendroaspis'' (which literally means "tree asp") in the family Elapidae. Four extant species are recognised currently; three of those four species are essentially arboreal and green in colour, whereas the black mamba, ''Dendroaspis polylepis'', is largely terrestrial and generally brown or grey in colour. All are native to various regions in sub-Saharan Africa and all are feared throughout their ranges, especially the black mamba. In Africa there are many legends and stories about mambas. also at/ref> Behaviour The three green species of mambas are arboreal, whereas the black mamba is largely terrestrial. The black mamba is one of the largest and most venomous snakes in Africa. All four species are active diurnal hunters, preying on birds, lizards, and small mammals. At nightfall some species, especially the terrestrial black mamba, shelter in a lair. A mamba may retain the same lair for years. Mambas and cob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granule Cells
A granule is a large particle or grain. It can refer to: * Granule (cell biology), any of several submicroscopic structures, some with explicable origins, others noted only as cell type-specific features of unknown function ** Azurophilic granule, a structure characteristic of the azurophil eukaryotic cell type ** Chromaffin granule, a structure characteristic of the chromophil eukaryotic cell type. * Astrophysics and geology: ** Granule (solar physics), a visible structure in the photosphere of the Sun arising from activity in the Sun's convective zone ** Martian spherules, spherical granules of material found on the surface of the planet Mars ** Granule (geology), a specified particle size of 2–4 millimetres (-1 to -2 on the φ scale) * Granule, in pharmaceutical terms, small particles gathered into a larger, permanent aggregate in which the original particles can still be identified * Granule (Oracle DBMS), a unit of contiguously allocated virtual memory * Granular synthesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granule Cell
A granule is a large particle or grain. It can refer to: * Granule (cell biology), any of several submicroscopic structures, some with explicable origins, others noted only as cell type-specific features of unknown function ** Azurophilic granule, a structure characteristic of the azurophil eukaryotic cell type ** Chromaffin granule, a structure characteristic of the chromophil eukaryotic cell type. * Astrophysics and geology: ** Granule (solar physics), a visible structure in the photosphere of the Sun arising from activity in the Sun's convective zone ** Martian spherules, spherical granules of material found on the surface of the planet Mars ** Granule (geology), a specified particle size of 2–4 millimetres (-1 to -2 on the φ scale) * Granule, in pharmaceutical terms, small particles gathered into a larger, permanent aggregate in which the original particles can still be identified * Granule (Oracle DBMS), a unit of contiguously allocated virtual memory * Granular synthesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drug Intolerance
Drug intolerance or drug sensitivity refers to an inability to tolerate the adverse effects of a medication, generally at therapeutic or subtherapeutic doses. Conversely, a patient is said to be "tolerating" a drug when they can tolerate its adverse effects. Some instances of drug intolerance are known to result from genetic variations in drug metabolism. Pathophysiology Drugs in systemic circulation have a certain concentration in the blood, which serves as a surrogate marker for how much drug will be delivered throughout the body (how much drug the rest of the body will "see"). There exists a minimum concentration of drug within the blood that will give rise to the intended therapeutic effect ( minimum effective concentration, MEC), as well as a minimum concentration of drug that will give rise to an unintended adverse drug event (minimum toxic concentration, MTC). The difference between these two values is generally referred to as the therapeutic window. Different drugs have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurons
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. Non-animals like plants and fungi do not have nerve cells. Neurons are typically classified into three types based on their function. Sensory neurons respond to stimuli such as touch, sound, or light that affect the cells of the sensory organs, and they send signals to the spinal cord or brain. Motor neurons receive signals from the brain and spinal cord to control everything from muscle contractions to glandular output. Interneurons connect neurons to other neurons within the same region of the brain or spinal cord. When multiple neurons are connected together, they form what is called a neural circuit. A typical neuron consists of a cell body (soma), dendrites, and a single axon. The soma is a compact structure, and the axon and dend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Affinity (pharmacology)
In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein. The binding typically results in a change of conformational isomerism (conformation) of the target protein. In DNA-ligand binding studies, the ligand can be a small molecule, ion, or protein which binds to the DNA double helix. The relationship between ligand and binding partner is a function of charge, hydrophobicity, and molecular structure. Binding occurs by intermolecular forces, such as ionic bonds, hydrogen bonds and Van der Waals forces. The association or docking is actually reversible through dissociation. Measurably irreversible covalent bonding between a ligand and target molecule is atypical in biological systems. In contrast to the definition of liga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Channels
Potassium channels are the most widely distributed type of ion channel found in virtually all organisms. They form potassium-selective pores that span cell membranes. Potassium channels are found in most cell types and control a wide variety of cell functions. Function Potassium channels function to conduct potassium ions down their electrochemical gradient, doing so both rapidly (up to the diffusion rate of K+ ions in bulk water) and selectively (excluding, most notably, sodium despite the sub-angstrom difference in ionic radius). Biologically, these channels act to set or reset the resting potential in many cells. In excitable cells, such as neurons, the delayed counterflow of potassium ions shapes the action potential. By contributing to the regulation of the cardiac action potential duration in cardiac muscle, malfunction of potassium channels may cause life-threatening arrhythmias. Potassium channels may also be involved in maintaining vascular tone. They also regulate ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
