CHRNA4 and early-onset autosomal dominant Alzheimer disease: The α7 subtype has high permeability to Ca2+ ions, relative to other nAChRs, and is a potential target for treatment of Parkinson's disease,13 inflammatory bowel disease,14 and cognition deficits in schizophrenia15 and Alzheimer's disease.16 We constructed a cell line coexpressing the α7 subunit with RIC-3, a chaperone that increases trafficking of several nAChR subtypes to the cell surface.17 We conducted positive modulator experiments in α7/RIC-3-CHO cells in the same manner as shown for the α4β2 subtype and obtained α7 EC50 values presented in Table 4 and Figure 5B.