Like the other type of acetylcholine receptor—the muscarinic acetylcholine receptor (mAChR)—the nAChR is triggered by the binding of the neurotransmitter acetylcholine (ACh).
"J Pharmacol Exp Ther" volume: 265 pp 1455–1473Lena C, Changeux J–P (1993): Allosteric modulations of the nicotinic acetylcholine receptor.