acetylcholine

Acetylcholine is a neurotransmitter which manages impulses from one cell to another in the brain, the central part of the sympathetic nervous system and the whole of the parasympathetic nervous system. In the brain it improves plasticity and excitability.

Plasticity is important for learning and short-term memory. In the autonomic nervous system acetylcholine is mainly involved in maintenance and adaptation after a stress response. In the rest of the body, acetylcholine transfers impulses from nerve cells to smooth muscle, skeletal muscle and many glands such as those in the digestive system, where it increases the flow of saliva and other digestive activities. Too much acetylcholine causes convulsions and too little acetylcholine causes poor muscle coordination. However, in the heart it reduces contraction and slows heart rate. Any drug or chemical which increases the effect of acetylcholine is called cholinergic while drugs that reduce the effects of acetylcholine are called anticholinergic drugs. Cholinergic drugs are used, for example, in Alzheimer’s disease, where there is a shortage of acetylcholine activity. Anticholinergic substances such as Botox prevent acetylcholine from contracting muscles, and reduce wrinkles. Mandrake which is traditionally used for asthma and stomach cramps, as well as atropine, which we find in deadly nightshade (Belladonna) are also anticholinergic. Belladonna (used in Victorian times to enlarge women’s pupils to make them a ‘beautiful lady‘, hence the name) is one of the most poisonous plants and takes central stage in many books, fairy tales and films.