Curare
From Biocrawler, the free encyclopedia.
Curare refers to the alkaloid containing substance obtained from one of several plants, the purified products of which are used as skeletal muscle relaxants. Curare has been superseded by a number of Curare-like agents that have a similar pharmacodynamic profile but with fewer side effects.
Curare is an example of a non-depolarising muscle relaxant which blocks the acetylcholine receptors on the post synaptic membrane of the neuromuscular junction.
Curare has also been used historically as a paralyzing poison by South American indigenous people. The prey is killed by asphyxiation as the respiratory muscles are unable to contract resulting in apnea.
Plants from which curare can be extracted
- Strychnos toxifera
- Chondrodendron tomentosum
Curare and anaesthesia
Modern anaesthesia serves two primary purposes: to reduce patient suffering and to relax the patient's muscles so that operations can be carried out without interference. Early anaesthesiologists tried to use a single substance for both purposes. For certain kinds of surgery, this meant that patients had to be very deeply anaesthetized with ether or cyclopropane in order to relax their muscles sufficiently. Such deep anaesthesia risked killing patients that were elderly or had heart conditions.
On January 23, 1942, Dr. Harold Griffith and Dr. Enid Johnson gave a synthetic preparation of curare (Intracostin) to a patient undergoing an appendectomy (to supplement conventional anaesthesia) and obtained a safe, short-term, local relaxation of the muscles. After using the same technique in 25 more cases, Dr. Griffith published a paper recommending the use of Intracostin in many kinds of surgery. By 1945 Intracostin was being used in more than ten thousand operations a month. Modern anaesthetists have at their disposal a variety of muscle relaxants for use as a standard component of anaesthesia.
The ability to produce muscle relaxation independently from anaesthesia has permitted anaesthesiologists to adjust the two effects as needed to ensure that their patients are safely unconscious and sufficiently relaxed to permit surgery. However, it has also made possible anaesthesia awareness, a case where through error or accident a patient remains fully conscious and sensitive to pain but cannot move to indicate this during the surgery.
References
- Anesthesia before and after curare (http://www.general-anaesthesia.com/curare.html) (retrieved June 20 2005)
- Harold Griffith (http://collections.ic.gc.ca/heirloom_series/volume6/204-205.htm) (retrieved June 20 2005)
 | This medical treatment article is a stub. You can help Biocrawler by expanding it (http://www.biocrawler.com/w/index.php?title=Curare&action=edit). |
