I apologize for not posting last week. I would make an excuse about being busy, but what’s the point? As I mentioned a couple of weeks ago I was interested in curare. Of all the phytochemicals useful to humankind, curare is, perhaps, most important to modern surgery. I vaguely remember going under or waking up from anesthesia as before or after getting my wisdom teeth out. I don't know what gave gave me to knock me out...I think I asked them (before I may have made a joke about breast implants?) but I think they told me I wouldn't remember anyways... I'm hoping it was something similar to curare.
Native Amazonians, presumably through trial and error, found a poison that renders its victim dead after it enters the bloodstream. Although they were likely using this poison for thousands of years, western culture became fascinated with it and took centuries to isolate the causal chemical. During the course of the chemical’s elucidation, people like Condamine, Humbolt, Waterton, Sir Walter Raleigh, were among the naturalists and explorers who documented or collected plants used in the preparation of the arrow poison. Slews of scientists experimented, but Sir Henry Dale followed by Otto Loewl determined it must be similar to acetyl-choline. In fact, the chemical inhibits the neurotransmitter acetyl-choline by binding to its target site. The result is relaxation of motor neurons and the diaphragm, which can result in death (1).
Obviously, the chemical is called curare, but it warrants a little disambiguation. The arrow poison developed by Amazonian Indians was/is made with several adjuvants. The entire concoction has come to be known as curare, but only one chemical (or one of its derivatives) are responsible for inducing a paralyzed state. The alkaloid d-tubocurarine, which causes paralysis is produced by species Strychnos (Loganaceae) and Chondrodendron (Menispermaceae). d-tubocurarine is commonly called curare (2).
Okay. So that was brief, brief explanation of what curare is and where it comes from. Clinical experiments with pure forms of d-tubocurarine were eventually shown to have no negative effects on patients and went on to be the standard for anesthetics (1). This excerpt from Griffiths and Johnson’s 1942 description of clinical curare use perfectly describes the wonder-drug potential: “Under cyclopropane anesthesia, relaxation of the anal sphincter was unsatisfactory. Immediately after the administration of 5c.c. Intocostrin [d-tubocurarine], complete relaxation was obtained, and the operation was easily performed (4).”
As I mentioned, curare, the arrow-poison, was from the Amazon. However, ethnobotanists have also found arrow poisons used by African and Southeast Asian tribes containing similar chemical constituents (3). Strychnos species take on a few different habits like lianas, climbing shrubs or even small trees. Depending where you are in the tropical world, the bark or roots may be used to extract poison. In the Amazon, after a little processing, the poison would be applied to darts for hunting. The meat of an animal contaminated with poison can ingested because the poison is not absorbed through the digestive tract! So cool!
Stuff Cited:
(1)Lee, M.R. 2005. Curare: the South American arrow poison. J R Coll Physicians Edinburgh 35:83-92
(2)Philippe, G., Angenot, L., Tits, M., & Frederich, M. 2004. About the toxicity of some Strychnos species and their alkaloids. Toxicon 44: 405-416.
(3) Philippe, G., & Angenot, L. 2005. Recent developments in the field of arrow and dart poisons. J. Ethnopharmacology 100: 85-91.
(4)Griffith, H.R. & Johnson, G.E. 1945. The use of curare in general anesthesia.
