We introduce the term 'silent agonists' to describe ligands that can place the α7 nicotinic acetylcholine receptor (nAChR) into a desensitized state with little or no apparent activation of the ion channel, forming a complex that can subsequently generate currents when treated with an allosteric modulator. KC-1 (5′-phenylanabaseine) was synthesized and identified as a new silent agonist for the α7 nAChR; it binds to the receptor but does not activate α7 ...