Drug that binds to but does not activate muscarinic cholinergic receptors
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Muscarinic acetylcholine receptor antagonist
Drug class
Skeletal formula of scopolamine, a nonselective antagonist of the muscarinic receptors
Class identifiers
Use
Allergies, asthma, atrial fibrillation with bradycardia,[1] motion sickness, Parkinson's disease, etc.
ATC code
V
Biological target
Metabotropic acetylcholinergic receptors
External links
MeSH
D018727
Legal status
In Wikidata
A muscarinic receptor antagonist (MRA), also called an antimuscarinic, 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 COPD, and neurological problems such as Parkinson's disease and Alzheimer's disease. A number of other drugs, such as antipsychotics and the tricyclic family of antidepressants, have incidental muscarinic antagonist activity which can cause unwanted side effects such as difficulty urinating, dry mouth and skin, and constipation.
Acetylcholine (often abbreviated ACh) is a neurotransmitter whose receptors are proteins found in synapses and other cell membranes. Besides responding to their primary neurochemical, neurotransmitter receptors can be sensitive to a variety of other molecules. Acetylcholine receptors are classified into two groups based on this:
muscarinic, which respond to muscarine
nicotinic, which respond to nicotine
Most muscarinic receptor antagonists are synthetic chemicals; however, the two most commonly used anticholinergics, scopolamine and atropine, are belladonna alkaloids, and are naturally extracted from plants such as Atropa belladonna, the deadly nightshade. The name "belladonna", Italian for "beautiful lady", is thought to derive from one of the antimuscarinic effects of these alkaloids: they were used by women for cosmetic purposes, to promote dilation of the pupils.[2]
Muscarinic antagonist effects and muscarinic agonist effects counterbalance each other for homeostasis.
Certain muscarinic antagonists can be classified into either long-acting muscarinic receptor antagonists (LAMAs) or short-acting muscarinic receptor antagonists (SAMAs), depending on when maximum effect occurs and for how long the effect persists.[3]
^"Hyoscyamine Subs for Pacemaker in Afib with Bradycardia". www.medpagetoday.com. May 14, 2018.
^Ritter, James (2020). Rang and Dale's pharmacology. R. J. Flower, Graeme Henderson, Yoon Kong Loke, David J. MacEwan, H. P. Rang (9th ed.). Edinburgh. p. 377. ISBN 978-0-7020-8060-9. OCLC 1081403059.{{cite book}}: CS1 maint: location missing publisher (link)
and 28 Related for: Muscarinic antagonist information
A muscarinic receptor antagonist (MRA), also called an antimuscarinic, is a type of anticholinergic agent that blocks the activity of the muscarinic acetylcholine...
agonists or antagonists. Acetylcholine (ACh) is a neurotransmitter found in the brain, neuromuscular junctions and the autonomic ganglia. Muscarinic receptors...
acetylcholine receptor Nicotinic agonist Muscarinic acetylcholine receptor Muscarinic agonist Muscarinicantagonist P. Taylor (1990). In Goodman and Gilman's...
A muscarinic agonist is an agent that activates the activity of the muscarinic acetylcholine receptor. The muscarinic receptor has different subtypes...
among others, is a type of anticholinergic (SAMA: short acting muscarinicantagonist) medication which is applied by different routes: inhaler, nebulizer...
either one on its own. Which type of long-acting agent, long-acting muscarinicantagonist (LAMA) such as tiotropium or long-acting beta agonist (LABA), is...
of the peripheral and central muscarinic acetylcholine receptors. Scopolamine acts as a nonspecific muscarinicantagonist at all four (M1, M2, M3, and...
Trospium chloride is a muscarinicantagonist used to treat overactive bladder. It has side effects typical of this class of drugs, namely dry mouth, stomach...
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Trospium chloride is a non-CNS penetrant non-selective muscarinicantagonist to quell peripheral muscarinic agonist-dependent side effects. Xanomeline's mechanism...
Clidinium bromide (INN) is an anticholinergic (specifically a muscarinicantagonist) drug. It may help symptoms of cramping and abdominal/stomach pain...
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...
receptors are in the brain and lungs. Scopolamine is a nonspecific muscarinicantagonist at all four (M1, M2, M3, and M4) receptor sites. Due to these compounds'...
of both olanzapine and the other drug. Olanzapine is a potent antagonist of the muscarinic M3 receptor, which may underlie its diabetogenic side effects...
doses of ketamine for recreational purposes. Ketamine is an NMDA receptor antagonist, accounting for most of its psychoactive effects. Ketamine was first synthesized...
antihistamine, or an antagonist of the histamine H1 receptor. A study found that dexchlorpheniramine had a Ki value of 20 to 30 μM for the muscarinic acetylcholine...
swallowing that occurs throughout the day. While clozapine is a muscarinicantagonist at the M1, M2, M3, and M5 receptors, clozapine is a full agonist...
Kunelius R, Laurén L (February 1988). "Effects of antiparkinsonian drugs on muscarinic receptor binding in rat brain, heart and lung". Pharmacology & Toxicology...
among others, is a long-acting bronchodilator (LAMA: long acting muscarinicantagonist) used in the management of chronic obstructive pulmonary disease...
Revefenacin is a bronchodilator that exerts its effect as a long-acting muscarinicantagonist. "Theravance Biopharma and Mylan Receive FDA Approval for Yupelri...
and reduces muscle spasm. It is in a class of drugs known as muscarinic receptor antagonists; acetylcholine is the neurotransmitter of the parasympathetic...
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is a muscarinicantagonist structurally similar to the neurotransmitter acetylcholine. Its mechanism of action involves blocking the muscarinic acetylcholine...
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It is a first generation selective H1 antagonist. Dimetindene is an atypical first generation H1 antagonist as it only minimally passes across the blood–brain...
effects of cyclobenzaprine are likely due to its antagonistic effect on histamine, serotonin, and muscarinic receptors.[medical citation needed] Agitation...
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