Muscarine, L-(+)-muscarine, or muscarin is a natural product found in certain mushrooms, particularly in Inocybe and Clitocybe species, such as the deadly C. dealbata. Mushrooms in the genera Entoloma and Mycena have also been found to contain levels of muscarine which can be dangerous if ingested. Muscarine has been found in harmless trace amounts in Boletus, Hygrocybe, Lactarius and Russula. Trace concentrations of muscarine are also found in Amanita muscaria, though the pharmacologically more relevant compound from this mushroom is the Z-drug-like alkaloid muscimol. A. muscaria fruitbodies contain a variable dose of muscarine, usually around 0.0003% fresh weight. This is very low and toxicity symptoms occur very rarely. Inocybe and Clitocybe contain muscarine concentrations up to 1.6%.
Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral nervous system, muscle, and many other tissues of many organisms. At the neuromuscular junction they are the primary receptor in muscle for motor nerve-muscle communication that controls muscle contraction. In the peripheral nervous system: (1) they transmit outgoing signals from the presynaptic to the postsynaptic cells within the sympathetic and parasympathetic nervous system, and (2) they are the receptors found on skeletal muscle that receive acetylcholine released to signal for muscular contraction. In the immune system, nAChRs regulate inflammatory processes and signal through distinct intracellular pathways. In insects, the cholinergic system is limited to the central nervous system.
Jean-Pierre Changeux is a French neuroscientist known for his research in several fields of biology, from the structure and function of proteins, to the early development of the nervous system up to cognitive functions. Although being famous in biological sciences for the MWC model, the identification and purification of the nicotinic acetylcholine receptor and the theory of epigenesis by synapse selection are also notable scientific achievements. Changeux is known by the non-scientific public for his ideas regarding the connection between mind and physical brain. As put forth in his book, Conversations on Mind, Matter and Mathematics, Changeux strongly supports the view that the nervous system functions in a projective rather than reactive style and that interaction with the environment, rather than being instructive, results in the selection amongst a diversity of preexisting internal representations.
Epibatidine is a chlorinated alkaloid that is secreted by the Ecuadoran frog Epipedobates anthonyi and poison dart frogs from the Ameerega genus. It was discovered by John W. Daly in 1974, but its structure was not fully elucidated until 1992. Whether epibatidine occurs naturally remains controversial due to challenges in conclusively identifying the compound from the limited samples collected by Daly. By the time that high-resolution spectrometry was used in 1991, there remained less than one milligram of extract from Daly's samples, raising concerns about possible contamination. Samples from other batches of the same species of frog failed to yield epibatidine.
In industrial chemistry, a stabilizer or stabiliser is a chemical that is used to prevent degradation.Heat and light stabilizers are added to plastics because they ensure safe processing and protect products against aging and weathering. The trend is towards fluid systems, pellets, and increased use of masterbatches. There are monofunctional, bifunctional, and polyfunctional stabilizers. In economic terms the most important product groups on the market for stabilizers are compounds based on calcium, lead, and tin stabilizers as well as liquid and light stabilizers. Cadmium-based stabilizers largely vanished in the last years due to health and environmental concerns.
Methyllycaconitine (MLA) is a diterpenoid alkaloid found in many species of Delphinium (larkspurs). In common with many other diterpenoid alkaloids, it is toxic to animals, although the acute toxicity varies with species. Methyllycaconitine was identified one of the principal toxins in larkspurs responsible for livestock poisoning in the mountain rangelands of North America. Methyllycaconitine has been explored as a possible therapeutic agent for the treatment of spastic paralysis, and it has been shown to have insecticidal properties. It has become an important molecular probe for studying the pharmacology of the nicotinic acetylcholine receptor.
Triacetonamine is an organic compound with the formula OC(CH2CMe2)2NH (where Me = CH3). It is a colorless or white solid that melts near room temperature. The compound is an intermediate in the preparation of 2,2,6,6-tetramethylpiperidine, a sterically hindered base and precursor to the reagent called TEMPO. Triacetonamine is formed by the poly-aldol condensation of acetone in the presence of ammonia and calcium chloride:
Capsazepine is a synthetic antagonist of capsaicin. It is used as a biochemical tool in the study of TRPV ion channels.
A nicotinic agonist is a drug that mimics the action of acetylcholine (ACh) at nicotinic acetylcholine receptors (nAChRs). The nAChR is named for its affinity for nicotine.
α-Cobratoxin is a substance of the venom of certain Naja cobras. It is a nicotinic acetylcholine receptor (nAChR) antagonist which causes paralysis by preventing the binding of acetylcholine to the nAChR.
The muscarinic acetylcholine receptor, also known as cholinergic/acetylcholine receptor M3, or the muscarinic 3, is a muscarinic acetylcholine receptor encoded by the human gene CHRM3.
The alpha-7 nicotinic receptor, also known as the α7 receptor, is a type of nicotinic acetylcholine receptor implicated in long-term memory, consisting entirely of α7 subunits. As with other nicotinic acetylcholine receptors, functional α7 receptors are pentameric [i.e., (α7)5 stoichiometry].
Tebanicline is a potent synthetic nicotinic (non-opioid) analgesic drug developed by Abbott. It was developed as a less toxic analog of the potent poison dart frog-derived compound epibatidine, which is about 200 times stronger than morphine as an analgesic, but produces extremely dangerous toxic side effects. Like epibatidine, tebanicline showed potent analgesic activity against neuropathic pain in both animal and human trials, but with far less toxicity than its parent compound. It acts as a partial agonist at neuronal nicotinic acetylcholine receptors, binding to both the α3β4 and the α4β2 subtypes.
Histrionicotoxins are a group of related toxins found in the skin of poison frogs from the family Dendrobatidae, notably Oophaga histrionica, which are native to Colombia. It is likely that, as with other poison frog alkaloids, histrionicotoxins are not manufactured by the amphibians, but absorbed from insects in their diet and stored in glands in their skin. They are notably less toxic than other alkaloids found in poison frogs, yet their distinct structure acts as a neurotoxin by non-competitive inhibition of nicotinic acetylcholine receptors.
4-Hydroxy-TEMPO or TEMPOL, formally 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, is a heterocyclic compound. Like the related TEMPO, it is used as a catalyst and chemical oxidant by virtue of being a stable aminoxyl radical. Its major appeal over TEMPO is that it is less expensive, being produced from triacetone amine, which is itself made via the condensation of acetone and ammonia. This makes it economically viable on an industrial scale.
Catharanthine is a terpene indole alkaloid produced by the medicinal plant Catharanthus roseus and Tabernaemontana divaricata. Catharanthine is derived from strictosidine, but the exact mechanism by which this happens is currently unknown. Catharanthine is one of the two precursors that form vinblastine, the other being vindoline.
The alpha-3 beta-2 nicotinic receptor, also known as the α3β2 receptor, is a type of nicotinic acetylcholine receptor, consisting of α3 and β2 subunits.
Dehydronorketamine (DHNK), or 5,6-dehydronorketamine, is a minor metabolite of ketamine which is formed by dehydrogenation of its metabolite norketamine. Though originally considered to be inactive, DHNK has been found to act as a potent and selective negative allosteric modulator of the α7-nicotinic acetylcholine receptor (IC50 = 55 nM). For this reason, similarly to hydroxynorketamine (HNK), it has been hypothesized that DHNK may have the capacity to produce rapid antidepressant effects. However, unlike ketamine, norketamine, and HNK, DHNK has been found to be inactive in the forced swim test (FST) in mice at doses up to 50 mg/kg. DHNK is inactive at the α3β4-nicotinic acetylcholine receptor (IC50 > 100 μM) and is only very weakly active at the NMDA receptor (Ki = 38.95 μM for (S)-(+)-DHNK). It can be detected 7–10 days after a modest dose of ketamine, and because of this, is useful in drug detection assays.
The neuronal acetylcholine receptor subunit alpha-5, or alpha-5 nicotinic acetylcholine receptor(α5 nAChR) also known as the α5 receptor is a type of ligand gated neuronal type subunit of the nicotinic acetylcholine receptor involved in pain regulation encoded in the human by the CHRNA5 gene. This receptor is commonly associated with nicotine addiction, immunotherapy, cancer, pain and attention.
Threohydrobupropion is a substituted amphetamine derivative—specifically a β-hydroxyamphetamine—and a major active metabolite of the antidepressant drug bupropion (Wellbutrin). Bupropion is a norepinephrine–dopamine reuptake inhibitor and nicotinic acetylcholine receptor negative allosteric modulator, with its metabolites contributing substantially to its activities.
