The Effects of Curare on Nerve Impulse

Updated April 17, 2017

Although curare is a potential nervous-system poison, medical texts, including "Goodman & Gilman's Pharmacological Basis of Therapeutics," agree on one thing: the discovery of its effects on nerve impulse was a milestone for anaesthesia practice, which opened the way for the discovery of better and safer muscle relaxants.


Curare is a generic term for South American arrow poisons, usually from the strychnos toxifera or chondrodendron tomentosum plants. Also known as tubocurarine, curare functions as a neuromuscular blocking agent, or muscle relaxant.

Location of Action

Curare acts at the junction between the nerve and muscle to block the transmission of nerve impulses. Nerve impulses are electrochemical messages that propagate along nerve fibres and muscle cells to produce an action.

Mechanism of Action

Curare competes with acetylcholine--or Ach--for receptors on muscle cells. Acetylcholine is a chemical messenger that normally transmits nerve impulses and activates muscle receptors.


When curare binds instead of acetylcholine, the receptors do not become activated, and there is loss of muscle function, paralysis and possibly death. Dosage and dosing intervals all determine the severity of curare's effect.

Time Frame

Curare immobilises muscles minutes after injection. However, its effects on nerve impulses are reversible and do not damage the nerve fibres.

Curare Poisoning

Anti-cholinesterase drugs, such as physostigmine or neostigmine, can reverse the effects of curare poisoning. These drugs block acetylcholine breakdown at the neuromuscular junction, so acetylcholine molecules can outnumber curare and activate unoccupied muscle receptors.

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About the Author

Suzanne Fantar has been writing online since 2009 as an outlet for her passion for fitness, nutrition and health. She enjoys researching and writing about health, but also takes interest in family issues, poetry, music, Christ, nature and learning. She holds a bachelor's degree in biological sciences from Goucher College and a MBA in healthcare management from the University of Baltimore.