Scorpions: Arthropods of the order Scorpiones, of which 1500 to 2000 species have been described. The most common live in tropical or subtropical areas. They are nocturnal and feed principally on insects and other arthropods. They are large arachnids but do not attack man spontaneously. They have a venomous sting. Their medical significance varies considerably and is dependent on their habits and venom potency rather than on their size. At most, the sting is equivalent to that of a hornet but certain species possess a highly toxic venom potentially fatal to humans. (From Dorland, 27th ed; Smith, Insects and Other Arthropods of Medical Importance, 1973, p417; Barnes, Invertebrate Zoology, 5th ed, p503)Scorpion Venoms: Venoms from animals of the order Scorpionida of the class Arachnida. They contain neuro- and hemotoxins, enzymes, and various other factors that may release acetylcholine and catecholamines from nerve endings. Of the several protein toxins that have been characterized, most are immunogenic.Scorpion Stings: The effects, both local and systemic, caused by the bite of SCORPIONS.Neurotoxins: Toxic substances from microorganisms, plants or animals that interfere with the functions of the nervous system. Most venoms contain neurotoxic substances. Myotoxins are included in this concept.Antivenins: Antisera used to counteract poisoning by animal VENOMS, especially SNAKE VENOMS.Toxins, Biological: Specific, characterizable, poisonous chemicals, often PROTEINS, with specific biological properties, including immunogenicity, produced by microbes, higher plants (PLANTS, TOXIC), or ANIMALS.Reptilian Proteins: Proteins obtained from species of REPTILES.Synaptosomes: Pinched-off nerve endings and their contents of vesicles and cytoplasm together with the attached subsynaptic area of the membrane of the post-synaptic cell. They are largely artificial structures produced by fractionation after selective centrifugation of nervous tissue homogenates.Sodium Channels: Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.Arachnida: A class of Arthropoda that includes SPIDERS; TICKS; MITES; and SCORPIONS.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Cockroaches: Insects of the order Dictyoptera comprising several families including Blaberidae, BLATTELLIDAE, Blattidae (containing the American cockroach PERIPLANETA americana), Cryptocercidae, and Polyphagidae.Bites and StingsKv1.3 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is the predominant VOLTAGE-GATED POTASSIUM CHANNEL of T-LYMPHOCYTES.Veratridine: A benzoate-cevane found in VERATRUM and Schoenocaulon. It activates SODIUM CHANNELS to stay open longer than normal.Potassium Channel Blockers: A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.Sea Anemones: The order Actiniaria, in the class ANTHOZOA, comprised of large, solitary polyps. All species are carnivorous.Charybdotoxin: A 37-amino acid residue peptide isolated from the scorpion Leiurus quinquestriatus hebraeus. It is a neurotoxin that inhibits calcium activated potassium channels.Lethal Dose 50: The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.Cnidarian Venoms: Venoms from jellyfish; CORALS; SEA ANEMONES; etc. They contain hemo-, cardio-, dermo- , and neuro-toxic substances and probably ENZYMES. They include palytoxin, sarcophine, and anthopleurine.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Saxitoxin: A compound that contains a reduced purine ring system but is not biosynthetically related to the purine alkaloids. It is a poison found in certain edible mollusks at certain times; elaborated by GONYAULAX and consumed by mollusks, fishes, etc. without ill effects. It is neurotoxic and causes RESPIRATORY PARALYSIS and other effects in MAMMALS, known as paralytic SHELLFISH poisoning.Hepatopancreas: A primitive form of digestive gland found in marine ARTHROPODS, that contains cells similar to those found in the mammalian liver (HEPATOCYTES), and the PANCREAS.Batrachotoxins: Batrachotoxin is the 20-alpha-bromobenzoate of batrachotoxin A; they are toxins from the venom of a small Colombian frog, Phyllobates aurotaenia, cause release of acetylcholine, destruction of synaptic vesicles and depolarization of nerve and muscle fibers.