PNU-120596 enhances Ca2+ flux mediated by an engineered variant of the human α7 nAChR. PNU-120596 enhances Ca2+ flux mediated by an engineered variant of the human α7 nAChR. A, Chemical structure of PNU-120596. B, Plot of the change in relative fluorescence units (ΔRFU) mediated by α7* expressed in SH-EP1 cells. Cells were pretreated with either vehicle (0.2% DMSO) or 3 μm PNU-120596 (first arrow) and subsequently challenged with either buffer or 100 μm ACh (second arrow). Open circles indicate cells treated first with DMSO and then challenged with buffer, gray squares indicate cells treated first with DMSO and then challenged with ACh, and black diamonds indicate cells treated first with PNU-120596 and then challenged with ACh. C, Concentration-response relationship of PNU-120596 determined from α7*-expressing SH-EP1 cells (EC50 = 216 ± 64 nm; n = 51). Error bars represent SEM. Raymond S. Hurst et al. J. Neurosci. 2005;25:4396-4405 ©2005 by Society for Neuroscience