1,8 Each of the five subunits which comprises the nAChR creates a water-filled pore by spanning the lipid bilayer (Figure 1). Each subunit is made up of 4 transmembrane segments; the second ...

The acetylcholine (ACh)-binding sites on the nAChR are located in the extracellular domain at subunit boundaries, and their structure and drug selectivity is being elucidated at the atomic level.