Nicotinic acetylcholine receptor

Nicotinic acetylcholine receptors, or nAChRs, are <a href="/facts/Receptor_(biochemistry)/tjTAC76a">receptor</a> <a href="/facts/Polypeptide/C4ltc7UG">polypeptides</a> that respond to the neurotransmitter <a href="/facts/Acetylcholine/v1d3wRUd">acetylcholine</a>. Nicotinic receptors also respond to drugs such as the agonist <a href="/facts/Nicotine/VQ6HcIrY">nicotine</a>. They are found in the central and peripheral nervous system, muscle, and many other tissues of many organisms. At the <a href="/facts/Neuromuscular_junction/Rkcqwqht">neuromuscular junction</a> they are the primary receptor in muscle for motor nerve-muscle communication that controls muscle contraction. In the <a href="/facts/Peripheral_nervous_system/KjVpVnHU">peripheral nervous system</a>: (1) they transmit outgoing signals from the presynaptic to the postsynaptic cells within the <a href="/facts/Sympathetic_nervous_system/hs8psNRd">sympathetic</a> and <a href="/facts/Parasympathetic_nervous_system/eNzCI8Yu">parasympathetic nervous system</a>, and (2) they are the receptors found on skeletal muscle that receive acetylcholine released to signal for muscular contraction. In the immune system, nAChRs regulate inflammatory processes and signal through distinct intracellular pathways. In <a href="/facts/Insect/IgDNvnUL">insects</a>, the <a href="/facts/Cholinergic/51ttI8RK">cholinergic</a> system is limited to the <a href="/facts/Central_nervous_system/k8I6To97">central nervous system</a>.
The nicotinic receptors are considered <a href="/facts/Cholinergic_receptors/wfRUApCd">cholinergic receptors</a>, since they respond to acetylcholine. Nicotinic receptors get their name from <a href="/facts/Nicotine/VQ6HcIrY">nicotine</a> which does not stimulate the <a href="/facts/Muscarinic_acetylcholine_receptor/caIdoqrW">muscarinic acetylcholine receptors</a> but selectively binds to the nicotinic receptors instead. The muscarinic acetylcholine receptor likewise gets its name from a chemical that selectively attaches to that receptor—<a href="/facts/Muscarine/9Sow1p3P">muscarine</a>. Acetylcholine itself binds to both muscarinic and nicotinic acetylcholine receptors.
As <a href="/facts/Ionotropic/gN9RkNC2">ionotropic</a> receptors, nAChRs are directly linked to ion channels. Some evidence suggests that these receptors can also use <a href="/facts/Second_messengers/J0eEENxQ">second messengers</a> (as <a href="/facts/Metabotropic_receptor/McU7DxqV">metabotropic receptors</a> do) in some cases. Nicotinic acetylcholine receptors are the best-studied of the ionotropic receptors.
Since nicotinic receptors help transmit outgoing signals for the sympathetic and parasympathetic systems, nicotinic receptor antagonists such as <a href="/facts/Hexamethonium/5xpAm1T2">hexamethonium</a> interfere with the transmission of these signals. Thus, for example, nicotinic receptor antagonists interfere with the <a href="/facts/Baroreflex/PuVw15ba">baroreflex</a> that normally corrects changes in blood pressure by sympathetic and parasympathetic stimulation of the heart.

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Nicotinic acetylcholine receptor