Cholinergic



The word choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation. Found in most animal tissues, choline is a primary component of the neurotransmitter acetylcholine and functions with inositol as a basic constituent of lecithin. 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 in a neurological perspective. The parasympathetic nervous system, 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, the basal forebrain, 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) is cholinergic if it is capable of producing, altering, or releasing acetylcholine ("indirect-acting") or mimicking its behaviour at one or more of the body's acetylcholine receptor types ("direct-acting").
 * A receptor is cholinergic if it uses acetylcholine as its neurotransmitter.
 * A synapse 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 quarternary 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, also known as a cholinergic agent, cholinergic agonist, or a parasympathomimetic drug, is any drug that functions to enhance the effects mediated by acetylcholine in the central nervous system, the peripheral nervous system, or both. These include acetylcholine's precursors and cofactors, acetylcholine receptor agonists,acetylcholinesterase inhibitors and cholinergic enzymes:


 * Acetylcholine receptor agonists
 * Alvameline
 * Muscarine (muscarinic receptors)
 * Nicotine (nicotinic receptors)
 * Pilocarpine (M3 receptors)
 * Suxamethonium (muscle type receptors)


 * Acetylcholine receptor antagonists
 * Scopolamine
 * Dicycloverine
 * Tolterodine
 * Oxybutynin
 * Ipratropium
 * Mamba Toxin (MT7)
 * Pirenzepine
 * Telenzepine


 * Acetylcholinesterase inhibitors (abbreviated AChEIs)
 * Donepezil
 * Galantamine
 * Huperzine A
 * Neostigmine
 * Physostigmine
 * Rivastigmine