The word cholinergic stems from the word choline, which refers to the quaternary ammonium salts which contain the N,N-trimethylethanolammonium cation. In food, choline is found in organ meats, egg yolk, wheat germ and brewer's yeast. Its function in the body is to prevent deposits of fat in the liver and encourage movement of fat into cells. Choline supplements are sometimes recommended for those suffering from liver disease or cirrhosis. It has some application in the treatment of depression, Tourrette's disease, some seizure disorders and schizophrenia. Pregnant women are urged to take supplements containing choline to prevent neural tube defects in their babies. Choline may have a role to play in decreasing swelling and inflammation in those suffering from asthma and arthritis.
The term cholinergic is used in neuroscience to describe a substance capable of producing, changing or releasing acetylcholine at one of the body's acetylcholine receptors. Receptors are considered cholinergic if it uses acetylcholine as its neurotransmitter, as is a synapse. Acetylcholine is the main transmitter used in the parasympathetic nervous system. This part of the nervous system is responsible for smooth muscle contractions, heart rate, bodily secretions and blood vessel dilation.
Cholinergic drugs, or agonists, are those which copy, suppress or enhance the actions of acetylcholine in the nervous system. There are some therapeutic applications for cholinergic medications, but they are also the primary source of the addictive properties in tobacco. The cholinergic drug scopolamine depresses the central nervous system and is useful in treating motion sickness, excessive salivation and bronchial secretions. It is also used by ophthalmologists to dilate a patient's pupils for examination.
The term cholinergic is used to describe any chemical or food that interacts with the acetylcholine receptors. The interactions include stimulating the neurotransmitter, dampening it or mimicking the effects of acetylcholine enough for the receptor to accept it.
