Nicotinic Acetylcholine Receptors

Abstract Acetylcholine, exquisitely evolved as a neurotransmitter, is made and released by the neurons that take the integrated output of the central nervous system throughout the body. At both neuromuscular junctions and autonomic ganglia, acetylcholine activates synaptic ion channels that take their name from the plant alkaloid nicotine, which is a mimic of the natural neurotransmitter. This chapter begins with the scientific discoveries related to the nicotinic acetylcholine receptors (nAChR) of the neuromuscular junction and how resulting insights led to an understanding of the fundamentals of synaptic transmission. The nAChR are one member of a superfamily of ligand-gated ion channels, and although in the brain excitatory neurotransmission is mediated by another family of synaptic receptors that are gated by glutamate, nicotinic receptors are important modulators of brain function and significant targets for drug development. In the brain, nAChR are targets for cognitive disorders and, tragically, responsible for tobacco addiction.