CHRNA7 and Alzheimer disease: Under physiological conditions, low level of Aβ particularly interacted with the α7 isoform via the nitric oxide/cGMP/protein kinase G pathway to activate the channels.388,389 Thus, α7-nAChR KO mice at 12-month-old showed Aβ elevation as a compensatory response of α7-nAChRs and exhibited AD-like pathologies.390