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.
The active ingredient in curare is D-tubocurarine.
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.