Cholinergic

Cholinergic

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The word choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium
Choline
Choline is a water-soluble essential nutrient. It is usually grouped within the B-complex vitamins. Choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation....

 cation. Found in most animal tissues, choline is a primary component of the neurotransmitter
Neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...

 acetylcholine
Acetylcholine
The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...

 and functions with inositol
Inositol
Inositol or cyclohexane-1,2,3,4,5,6-hexol is a chemical compound with formula 6126 or 6, a sixfold alcohol of cyclohexane. It exists in nine possible stereoisomers, of which the most prominent form, widely occurring in nature, is cis-1,2,3,5-trans-4,6-cyclohexanehexol, or myo-inositol...

 as a basic constituent of lecithin
Lecithin
Lecithin is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues, and in egg yolk, composed of phosphoric acid, choline, fatty acids, glycerol, glycolipids, triglycerides, and phospholipids .The word lecithin was originally coined in 1847 by...

. It prevents fat deposits in the liver and facilitates the movement of fats into the cells. The richest sources of choline are liver, kidneys, brains, wheat germ, brewer's yeast, and egg yolk. Therefore, cholinergic typically refers to acetylcholine
Acetylcholine
The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...

 in a neurological perspective. The parasympathetic nervous system
Parasympathetic nervous system
The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system . The ANS is responsible for regulation of internal organs and glands, which occurs unconsciously...

, which uses acetylcholine almost exclusively to send its messages, is said to be almost entirely cholinergic. Neuromuscular junctions, preganglionic neurons of the sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

, the basal forebrain
Basal forebrain
The basal forebrain is a collection of structures located ventrally to the striatum. It is considered to be the major cholinergic output of the central nervous system . It includes a group of structures that lie near the bottom of the front of the brain, including the nucleus basalis, diagonal band...

, and brain stem complexes are also cholinergic. In addition, the receptor for the merocrine sweat glands are also cholinergic since acetylcholine is released from post ganglionic sympathetic neurons.

In neuroscience and related fields, the term cholinergic is used in the following related contexts:
  • A substance (or ligand
    Ligand (biochemistry)
    In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. In a narrower sense, it is a signal triggering molecule, binding to a site on a target protein.The binding occurs by intermolecular forces, such as ionic bonds, hydrogen...

    ) is cholinergic if it is capable of producing, altering, or releasing acetylcholine
    Acetylcholine
    The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...

     ("indirect-acting") or mimicking its behaviour at one or more of the body's acetylcholine receptor
    Acetylcholine receptor
    An acetylcholine receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.-Classification:...

     types ("direct-acting").
  • A receptor
    Receptor (biochemistry)
    In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

     is cholinergic if it uses acetylcholine as its neurotransmitter.
  • A synapse
    Synapse
    In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell...

     is cholinergic if it uses acetylcholine as its neurotransmitter.

Structure activity relationship for cholinergic drugs


1. molecule must possess a nitrogen atom capable of bearing a positive charge, preferably a quaternary ammonium salt.

2. for maximum potency, the size of the alkyl groups substituted on the Nitrogen should not exceed the size of a methyl group.

3. The molecule should have an oxygen atom, preferably an ester-like oxygen capable of participating in a hydrogen bond.

4. There should be a two-carbon unit between the oxygen atom and the nitrogen atom.

A cholinergic drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...

, also known as a cholinergic agent, cholinergic agonist, or a parasympathomimetic drug, is any drug that functions to enhance the effects mediated by acetylcholine
Acetylcholine
The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...

 in the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

, the peripheral nervous system
Peripheral nervous system
The peripheral nervous system consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain...

, or both. These include acetylcholine's precursors
Precursor (chemistry)
In chemistry, a precursor is a compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway....

 and cofactors
Cofactor (biochemistry)
A cofactor is a non-protein chemical compound that is bound to a protein and is required for the protein's biological activity. These proteins are commonly enzymes, and cofactors can be considered "helper molecules" that assist in biochemical transformations....

, acetylcholine receptor
Acetylcholine receptor
An acetylcholine receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.-Classification:...

 agonist
Agonist
An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...

s,acetylcholinesterase inhibitors and cholinergic enzymes:
  • Acetylcholine receptor
    Acetylcholine receptor
    An acetylcholine receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.-Classification:...

     agonist
    Agonist
    An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell. Agonists often mimic the action of a naturally occurring substance...

    s
    • Alvameline
      Alvameline
      Alvameline is a M1 receptor agonist and M2/M3 receptor antagonist that was under investigation for the treatment of Alzheimer's disease, but produced poor results in clinical trials and was subsequently discontinued....

    • Muscarine
      Muscarine
      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...

       (muscarinic receptors)
    • Nicotine
      Nicotine
      Nicotine is an alkaloid found in the nightshade family of plants that constitutes approximately 0.6–3.0% of the dry weight of tobacco, with biosynthesis taking place in the roots and accumulation occurring in the leaves...

       (nicotinic receptors)
    • Pilocarpine
      Pilocarpine
      Pilocarpine is a parasympathomimetic alkaloid obtained from the leaves of tropical American shrubs from the genus Pilocarpus. It is a non-selective muscarinic receptor agonist in the parasympathetic nervous system, which acts therapeutically at the muscarinic acetylcholine receptor M3 due to its...

       (M3 receptors)
    • Suxamethonium (muscle type receptors)

  • Acetylcholine receptor
    Acetylcholine receptor
    An acetylcholine receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.-Classification:...

     antagonist
    Antagonist
    An antagonist is a character, group of characters, or institution, that represents the opposition against which the protagonist must contend...

    s
    • Scopolamine
      Scopolamine
      Scopolamine, also known as levo-duboisine, and hyoscine, is a tropane alkaloid drug with muscarinic antagonist effects. It is among the secondary metabolites of plants from Solanaceae family of plants, such as henbane, jimson weed and Angel's Trumpets , and corkwood...

    • Dicycloverine
    • Tolterodine
      Tolterodine
      Tolterodine is an antimuscarinic drug that is used to treat urinary incontinence.It is marketed by Pfizer in Canada and the United States by its brand name Detrol. In Egypt it is also found under the trade names Tolterodine by Sabaa and Incont L.A...

    • Oxybutynin
      Oxybutynin
      Oxybutynin is an anticholinergic medication used to relieve urinary and bladder difficulties, including frequent urination and inability to control urination , by decreasing muscle spasms of the bladder. It competitively antagonizes the M1, M2, and M3 subtypes of the muscarinic acetylcholine...

    • Ipratropium
      Ipratropium
      Ipratropium bromide is an anticholinergic drug used for the treatment of chronic obstructive pulmonary disease and acute asthma. It blocks the muscarinic acetylcholine receptors in the smooth muscles of the bronchi in the lungs, opening the bronchi...

    • Mamba Toxin (MT7)
    • Pirenzepine
      Pirenzepine
      Pirenzepine is used in the treatment of peptic ulcers, as it reduces gastric acid secretion and reduces muscle spasm. It is in a class of drugs known as muscarinic receptor antagonists - acetylcholine being the neurotransmitter of the parasympathetic nervous system which initiates the...

    • Telenzepine
      Telenzepine
      Telenzepine is an anticholinergic or sympatholytic used in the treatment of peptic ulcers. Telenzepine is atropisomeric, in other words the molecule has a stereogenic C–N-axis in neutral aqueous solution it displays a half-life for racemization of the order of 1000 years. The enantiomers have been...


  • Acetylcholinesterase inhibitor
    Acetylcholinesterase inhibitor
    An acetylcholinesterase inhibitor or anti-cholinesterase is a chemical that inhibits the cholinesterase enzyme from breaking down acetylcholine, increasing both the level and duration of action of the neurotransmitter acetylcholine.- Uses :Acetylcholinesterase inhibitors:* Occur naturally as...

    s (abbreviated AChEIs)
    • Donepezil
      Donepezil
      Donepezil, marketed under the trade name Aricept by its developer Eisai and partner Pfizer, is a centrally acting reversible acetylcholinesterase inhibitor. Its main therapeutic use is in the palliative treatment of mild to moderate Alzheimer's disease. Common side effects include...

    • Galantamine
      Galantamine
      Galantamine is used for the treatment of mild to moderate Alzheimer’s disease and various other memory impairments, in particular those of vascular origin...

    • Huperzine A
      Huperzine A
      Huperzine A is a naturally occurring sesquiterpene alkaloid compound found in the plant firmoss Huperzia serrata. and in varying quantities in other Husperzia spp.including H. elmeri, H. carinat, H. aqualupian,...

    • Neostigmine
      Neostigmine
      Neostigmine is a parasympathomimetic that acts as a reversible acetylcholinesterase inhibitor.- Synthesis :Neostigmine was first synthesized by Aeschlimann and Reinert in 1931....

    • Physostigmine
      Physostigmine
      Physostigmine is a parasympathomimetic alkaloid, specifically, a reversible cholinesterase inhibitor. It occurs naturally in the Calabar bean....

    • Rivastigmine
      Rivastigmine
      Rivastigmine is a parasympathomimetic or cholinergic agent for the treatment of mild to moderate dementia of the Alzheimer’s type and dementia due to Parkinson's disease. The drug can be administered orally or via a transdermal patch; the latter form reduces the prevalence of side effects, which...


See also

  • Adrenergic
    Adrenergic
    An adrenergic agent is a drug, or other substance, which has effects similar to, or the same as, epinephrine . Thus, it is a kind of sympathomimetic agent...

  • Dopaminergic
    Dopaminergic
    Dopaminergic means related to the neurotransmitter dopamine. For example, certain proteins such as the dopamine transporter , vesicular monoamine transporter 2 , and dopamine receptors can be classified as dopaminergic, and neurons which synthesize or contain dopamine and synapses with dopamine...

  • GABAergic
  • Nootropic
    Nootropic
    Nootropics , also referred to as smart drugs, brain steroids, memory enhancers, cognitive enhancers, and intelligence enhancers, are drugs, supplements, nutraceuticals, and functional foods that improve mental functions such as cognition, memory, intelligence, motivation, attention, and concentration...

  • Serotonergic
    Serotonergic
    Serotonergic or serotoninergic means "related to the neurotransmitter serotonin". A synapse is serotonergic if it uses serotonin as its neurotransmitter...

  • Glutamatergic
  • Racetam
    Racetam
    Racetams are a class of nootropic drugs that share a pyrrolidone nucleus.-Mechanism:There is no generally accepted mechanism for racetams. They generally show no affinity for the most important receptors, although modulation of most important central neurotransmitters, including acetylcholine and...