A highly neurotoxic polypeptide from the venom of the honey bee (Apis mellifera). It consists of 18 amino acids with two disulfide bridges and causes hyperexcitability resulting in convulsions and respiratory paralysis.
Venoms obtained from Apis mellifera (honey bee) and related species. They contain various enzymes, polypeptide toxins, and other substances, some of which are allergenic or immunogenic or both. These venoms were formerly used in rheumatism to stimulate the pituitary-adrenal system.
A 37-amino acid residue peptide isolated from the scorpion Leiurus quinquestriatus hebraeus. It is a neurotoxin that inhibits calcium activated potassium channels.
A major class of calcium-activated potassium channels that are found primarily in excitable CELLS. They play important roles in the transmission of ACTION POTENTIALS and generate a long-lasting hyperpolarization known as the slow afterhyperpolarization.
Endogenously-synthesized compounds that influence biological processes not otherwise classified under ENZYMES; HORMONES or HORMONE ANTAGONISTS.
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.
Potassium channels whose activation is dependent on intracellular calcium concentrations.
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)
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.
That phase of a muscle twitch during which a muscle returns to a resting position.
An inhibitor of nitric oxide synthetase which has been shown to prevent glutamate toxicity. Nitroarginine has been experimentally tested for its ability to prevent ammonia toxicity and ammonia-induced alterations in brain energy and ammonia metabolites. (Neurochem Res 1995:200(4):451-6)
A major class of calcium-activated potassium channels that were originally discovered in ERYTHROCYTES. They are found primarily in non-excitable CELLS and set up electrical gradients for PASSIVE ION TRANSPORT.
One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Arteries which arise from the abdominal aorta and distribute to most of the intestines.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
A neurotransmitter found at neuromuscular junctions, autonomic ganglia, parasympathetic effector junctions, a subset of sympathetic effector junctions, and at many sites in the central nervous system.
An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.
A potassium-channel opening vasodilator that has been investigated in the management of hypertension. It has also been tried in patients with asthma. (Martindale, The Extra Pharmacopoeia, 30th ed, p352)
Drugs used to cause dilation of the blood vessels.
A neuromuscular blocker and active ingredient in CURARE; plant based alkaloid of Menispermaceae.
Paracrine substances produced by the VASCULAR ENDOTHELIUM with VASCULAR SMOOTH MUSCLE relaxation (VASODILATION) activities. Several factors have been identified, including NITRIC OXIDE and PROSTACYCLIN.
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
A topical bacteriostat that is available as various salts. It is used in wound dressings and mouth infections and may also have antifungal action, but may cause skin ulceration.
Use of electric potential or currents to elicit biological responses.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
A major class of calcium activated potassium channels whose members are voltage-dependent. MaxiK channels are activated by either membrane depolarization or an increase in intracellular Ca(2+). They are key regulators of calcium and electrical signaling in a variety of tissues.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
A non-selective inhibitor of nitric oxide synthase. It has been used experimentally to induce hypertension.
A non-steroidal anti-inflammatory agent (NSAID) that inhibits the enzyme cyclooxygenase necessary for the formation of prostaglandins and other autacoids. It also inhibits the motility of polymorphonuclear leukocytes.
A powerful vasodilator used in emergencies to lower blood pressure or to improve cardiac function. It is also an indicator for free sulfhydryl groups in proteins.
Inorganic compounds that contain barium as an integral part of the molecule.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The recording of muscular movements. The apparatus is called a myograph, the record or tracing, a myogram. (From Stedman, 25th ed)
An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.
Insect members of the superfamily Apoidea, found almost everywhere, particularly on flowers. About 3500 species occur in North America. They differ from most WASPS in that their young are fed honey and pollen rather than animal food.
Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)
A sulfur-containing analog of butyrylcholine which is hydrolyzed by butyrylcholinesterase to butyrate and thiocholine. It is used as a reagent in the determination of butyrylcholinesterase activity.
A sweet viscous liquid food, produced in the honey sacs of various bees from nectar collected from flowers. The nectar is ripened into honey by inversion of its sucrose sugar into fructose and glucose. It is somewhat acidic and has mild antiseptic properties, being sometimes used in the treatment of burns and lacerations.
Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.