A drug used in the form of eye-drops to treat glaucoma.
Also known as eserine. An alkaloid (see ALKALOIDS) obtained from Calabar bean, the seed of Physostigma venenosum, a climbing plant of West Africa. Its action depends on the presence of two alkaloids, the one known as physostigmine or eserine, the other as calabarine, the former of these being much the more important.
Action Physostigmine produces the same e?ect as stimulation of the PARASYMPATHETIC NERVOUS SYSTEM: i.e. it constricts the pupil of the eye, stimulates the gut, increases the secretion of saliva, stimulates the bladder, and increases the irritability of voluntary muscle. In poisonous doses it brings on a general paralysis.
Uses It is used in medicine in the form of eye drops or ointment to treat GLAUCOMA.
An acetic-acid ester of the organic base choline, acetylcholine is one of the substances which mediates the transmission of nerve impulses from one nerve to another, or from a nerve to the organ it acts on, such as muscles. It acts on both muscarinic receptors (blocked by ATROPINE and responsible for ganglionic and parasympathetic transmission and also for sympathetic innervation of sweat glands – see under AUTONOMIC NERVOUS SYSTEM) and nicotinic receptors (responsible for the transmission of nerve impulses to muscles and blocked by curare, thus causing paralysis). Acetylcholine is rapidly destroyed by cholinesterase, an ENZYME present in the blood. ANTICHOLINERGIC drugs such as PHYSOSTIGMINE prolong the action of acetylcholine.... acetylcholine
Substances found commonly in various plants. They are natural nitrogenous organic bases and combine with acids to form crystalline salts. Among alkaloids, morphine was discovered in 1805, strychnine in 1818, quinine and ca?eine in 1820, nicotine in 1829, and atropine in 1833. Only a few alkaloids occur in the animal kingdom, the outstanding example being ADRENALINE, which is formed in the medulla of the suprarenal, or adrenal, gland. Alkaloids are often used for medicinal purposes. The name of an alkaloid ends in ‘ine’ (in Latin, ‘ina’).
Neutral principals are crystalline substances with actions similar to those of alkaloids but having a neutral reaction. The name of a neutral principal ends in ‘in’, e.g. digitalin, aloin.
The following are the more important alkaloids, with their source plants:
Aconite, from Monkshood.
Atropine, from Belladonna (juice of Deadly
Nightshade).
Cocaine, from Coca leaves.
Hyoscine, from Henbane.
Morphine, Codeine, from Opium (juice of
Poppy). Thebaine, Nicotine, from Tobacco. Physostigmine, from Calabar beans. Pilocarpine, from Jaborandi leaves. Quinidine, from Cinchona or Peruvian bark. Strychnine, from Nux Vomica seeds.... alkaloids
Any compound that inhibits the activity of CHOLINESTERASE, thus permitting ACETYLCHOLINE to continue its function of transmitting nerve impulses. Drugs with anticholinesterase properties include distigmine, NEOSTIGMINE and PHYSOSTIGMINE.... anticholinesterase
Health Encyclopedia