Curare

Since 1942 there have been about 50 different relaxants used in clinical anesthesia. Tubocurarine, whose chemical structure was determined 1935, is the prototype of a muscle relaxant that still contains the alkaloid constituent of curare and produces a similar physiological effect. Another semisynthetic derivative of tubocurarine is even more potent. It is given intravenously since it is not active when taken orally.

Anesthetic muscle relaxants block nerve impulses between the junctions of the nerve and muscle. It is believed they accomplish this task preventing the acceptance of acetylcholine, which is a chemical neurotransmitter, by the muscle fiber. In addition to the main clinical use of curare is as an accessory drug in surgical anesthesia to obtain relaxation of skeletal muscle, it is also used to facilitate diagnostic procedures, such as laryngoscopy and endoscopy. It is also used in cases of tetanus and myasthenia gravis, an autoimmune disorder.