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Himbacine
Himbacine is an alkaloid isolated from the bark of Australian magnolias. Himbacine has been synthesized using a Diels-Alder reaction as a key step. Himbacine's activity as a muscarinic receptor antagonist, with specificity for the muscarinic acetylcholine receptor M2, made it a promising starting point in Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ... research. The development of a muscarinic antagonist based on himbacine failed but an analog, vorapaxar, has been approved by the FDA as a thrombin receptor antagonist. References Muscarinic antagonists Naphthofurans Piperidine alkaloids Lactones {{pharmacology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscarinic Antagonists
A muscarinic receptor antagonist (MRA) is a type of anticholinergic agent that blocks the activity of the muscarinic acetylcholine receptor. The muscarinic receptor is a protein involved in the transmission of signals through certain parts of the nervous system, and muscarinic receptor antagonists work to prevent this transmission from occurring. Notably, muscarinic antagonists reduce the activation of the parasympathetic nervous system. The normal function of the parasympathetic system is often summarised as "rest-and-digest", and includes slowing of the heart, an increased rate of digestion, narrowing of the airways, promotion of urination, and sexual arousal. Muscarinic antagonists counter this parasympathetic "rest-and-digest" response, and also work elsewhere in both the central and peripheral nervous systems. Drugs with muscarinic antagonist activity are widely used in medicine, in the treatment of low heart rate, overactive bladder, respiratory problems such as asthma and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vorapaxar
Vorapaxar (brand name Zontivity, formerly known as SCH 530348) is a thrombin receptor (protease-activated receptor, PAR-1) antagonist based on the natural product himbacine, discovered by Schering-Plough and developed by Merck & Co. Medical uses Vorapaxar is used for persons with a history of myocardial infarction (heart attack) or persons with peripheral arterial disease Peripheral artery disease (PAD) is an abnormal narrowing of arteries other than those that supply the heart or brain. When narrowing occurs in the heart, it is called coronary artery disease, and in the brain, it is called cerebrovascular diseas .... Studies have shown that this medication can reduce the rate of combined endpoint cardiovascular death, MI, stroke, and urgent coronary revascularization. Contraindications Vorapaxar is contraindicated for people with a history of stroke, transient ischemic attack, or intracerebral hemorrhage. In studies of vorapaxar on persons with prior ischemic stroke, there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galbulimima
''Galbulimima'' is a genus of flowering plants and the sole genus of the family Himantandraceae. Members of the family are found in the tropical zones of eastern Malaysia, the Moluccas, the Celebes, New Guinea, northern Australia and the Solomon Islands. Being classified in the magnoliids, this family is part of neither the monocots nor the eudicots and is related to families such as the Annonaceae, the Degeneriaceae, the Eupomatiaceae and the Magnoliaceae. The genus comprises from 1 to 3 species, according to different authorities, including ''Galbulimima belgraveana ''Galbulimima belgraveana'' is a hallucinogenic plant. Its common names include agara and white magnolia. It is native to northeastern Australia, Malaysia, and Papua New Guinea. Papuans (who tend to use this drug the most) boil the bark and the ....'' References Magnoliales Magnoliales genera {{Magnoliales-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscarinic
Muscarinic acetylcholine receptors, or mAChRs, are acetylcholine receptors that form G protein-coupled receptor complexes in the cell membranes of certain neurons and other cells. They play several roles, including acting as the main end-receptor stimulated by acetylcholine released from postganglionic fibers in the parasympathetic nervous system. Muscarinic receptors are so named because they are more sensitive to muscarine than to nicotine. Their counterparts are nicotinic acetylcholine receptors (nAChRs), receptor ion channels that are also important in the autonomic nervous system. Many drugs and other substances (for example pilocarpine and scopolamine) manipulate these two distinct receptors by acting as selective agonists or antagonists. Function Acetylcholine (ACh) is a neurotransmitter found in the brain, neuromuscular junctions and the autonomic ganglia. Muscarinic receptors are used in the following roles: Recovery receptors ACh is always used as the neuro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Receptor Antagonist
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. Antagonist drugs interfere in the natural operation of receptor proteins.Pharmacology Guide: In vitro pharmacology: concentration-response curves " '' GlaxoWellcome.'' Retrieved on December 6, 2007. They are sometimes called blockers; examples include alpha blockers, |
Muscarinic Acetylcholine Receptor M2
The muscarinic acetylcholine receptor M2, also known as the cholinergic receptor, muscarinic 2, is a muscarinic acetylcholine receptor that in humans is encoded by the ''CHRM2'' gene. Multiple alternatively spliced transcript variants have been described for this gene. Function Heart The M2 muscarinic receptors are located in the heart, where they act to slow the heart rate down to normal sinus rhythm after negative stimulatory actions of the parasympathetic nervous system, by slowing the speed of depolarization. They also reduce contractile forces of the atrial cardiac muscle, and reduce conduction velocity of the atrioventricular node (AV node). However, they have little effect on the contractile forces of the heart ventricle, ventricular muscle, slightly decreasing force. IQ A Dutch family study "a highly significant association" between the ''CHRM2'' gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alzheimer's Disease
Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term memory, remembering recent events. As the disease advances, symptoms can include primary progressive aphasia, problems with language, Orientation (mental), disorientation (including easily getting lost), mood swings, loss of motivation, self-neglect, and challenging behaviour, behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the typical life expectancy following diagnosis is three to nine years. The cause of Alzheimer's disease is poorly understood. There are many environmental and genetic risk factors associated with its development. The strongest genetic risk factor is from an alle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombin
Thrombin (, ''fibrinogenase'', ''thrombase'', ''thrombofort'', ''topical'', ''thrombin-C'', ''tropostasin'', ''activated blood-coagulation factor II'', ''blood-coagulation factor IIa'', ''factor IIa'', ''E thrombin'', ''beta-thrombin'', ''gamma-thrombin'') is a serine protease, an enzyme that, in humans, is encoded by the ''F2'' gene. Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions. History After the description of fibrinogen and fibrin, Alexander Schmidt hypothesised the existence of an enzyme that converts fibrinogen into fibrin in 1872. Prothrombin was discovered by Pekelharing in 1894. Physiology Synthesis Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is greatly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piperidine Alkaloids
Piperidine alkaloids are naturally occurring chemical compounds from the group of alkaloids, which are chemically derived from piperidine. Alkaloids with a piperidine building block are widespread and are usually further subdivided according to their occurrence and biogenetic origin. The most important representative of piperidine alkaloids is piperine, which is responsible for the pungent taste of pepper. The piperidine alkaloids also include the sedum alkaloids (e.g. sedamine), pelletierine, the lobelia alkaloids (e.g. lobeline), the conium alkaloids (such as coniine) and the pinus alkaloids. Piperin.svg, Piperine Lobeline Structural Formula V2.svg, Lobeline (S)-Coniine Structural Formula V.1.svg, (''S'')-Coniine (2R,8R)-Sedamine Structural Formula V4.svg, Sedamin Solenopsin Structural Formula V.1.svg, Solenopsin Solenopsin is a lipophilic alkaloid with the molecular formula C17H35N found in the venom of fire ants (''Solenopsis''). It is considered the primary toxin in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
