Curare

Discovery by the French chemist Charles Marie de La Condamine. Charles Marie de La Condamine participated in an expedition to the equator that started on 16 May 1735.

Curare is a collective term for various alkaloid poisons. For indigenous South American peoples (Orinoco and Amazon river basins) curare is used as a highly effective arrow poison. Curare is produced from extracts of the bark and leaves of various Strychnos species, although the recipes of the individual ethnic groups vary. The prototypical substance of curare (South American arrow poison) is D-Tubocurarin, an antagonist of the NM nicotine receptor on the motor end plate, which blocks the action of acetylcholine (peripheral, nondepolarising muscle relaxants).

According to the ways in which the poisons are stored, they are divided into tubo-curare, pot-curare and calabash-curare.

• Tubocurare: Tubocurare - occasionally written Tubo-Curare - is extracted from the bark of the species Chondrodendron tomentosum and various other species of the moonseed family (Menispermaceae). This form of curare is mainly produced by the indigenous peoples of Guyana and the upper Amazon basin. The name Tubo-Curare is derived from the storage of the liquid curare in bamboo tubes (Spanish: "tubo"). The main component is the D-Tubocurarin (Non-depolarising muscle relaxant), which was also used in anaesthesia, but is now obsolete due to the availability of newer substances with more favourable active profiles. Curare paralyzes the motor end plates of striated muscles (see below: Non-depolarizing muscle relaxants) even in extremely small amounts (1/100mg in frogs).
• Calabash curare: Calabash curare (also calabash curare) - is mainly obtained from species of the genus of nux vomica (strychnos) and contains various strychnos alkaloids such as alcoferin or C-toxiferin I, dihydroxiferin, C-curarin and C-calebasin. It is a paste-like mass which is traditionally kept in small hollowed gourds - Spanish: "calabaza").
• Pot curare, also known as pot curare, is typical of the Indians of the Orinoco basin. The poison is stored in small clay pots.

In anesthesia, curare was initially used as a muscle relaxant. The muscle-relaxing effect is the fourth component of anaesthesia after hypnosis, analgesia and amnesia. The effective ingredient of curare, tubocurarin (see figure), is no longer used because of its pronounced histamine-releasing effect and its inhibitory effect on transmission in sympathetic and parasympathetic ganglia.

Similar symptoms of poisoning as curare cause alkaloids from the seeds of the genus Erythrina. These alkaloids are effective when taken orally. The Indians in the Sierra of Tlaltizepam used "Colorines" for acts of revenge when they wanted someone to be "struck" (Roth L 1984 p. 327).

1. Roth L et al (1984) Plant poisons. In: Roth L et al. (Eds)Poisonous plants, plant allergy. Nikol Publishing Company mbH Hamburg S 327