Curare nicotinic cholinergic receptors

The effects of curare develop rapidly after it enters the body. Victims develop rapid weakness of voluntary muscles followed by paralysis, respiratory failure, and death. The cause is a blockade of nicotinic cholinergic receptors at the neuromuscular junctions in skeletal muscle. Unlike botulinum toxin, release of acetylcholine by the cholinergic nerve terminals is not affected. When curare is present, however, the acetylcholine that is released cannot bind to the receptors because they are reversibly occupied by the curare. As a consequence, nerve-muscle communication fails and paralysis ensues. 

Acetylcholine receptors. There are numerous receptors for ACh (Fig. 12—10), of which the major subtypes are nicotinic and muscarinic subtypes of cholinergic receptors. Classically, muscarinic receptors are simulated by the mushroom alkaloid muscarine and nicotinic receptors by the tobacco alkaloid nicotine. Nictotinic receptors are all ligand-gated, rapid-onset, and excitatory ion channels, which are blocked by curare. Muscarinic receptors, by contrast, are G protein—linked, can be excitatory or inhib-... 

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