Bis(7)-tacrine reduces glutamate(Glu)-induced apoptosis of RGCs in vivo. Eyes were enucleated at 18 h after intravitreal injection of glutamate(Glu) (20 nmol) or vehicle. TUNEL staining was performed and TUNEL-positive cells were counted in GCL. (A) A representative photograph of retina in the vehicle group. (B) A representative photograph of retina in the glutamate group. (C & D) A representative photograph of retina in the glutamate group with peritoneal injection of bis(7)-tacrine(0.2 mg/kg)(C) or memantine(20 mg/kg)(D). (E) The number of TUNEL-positive cells in GCL was counted. Each column represents means ± SEM (n = 6). *P < 0.05, **P < 0.01 versus glutamate group alone. GCL: ganglion cell layer, IPL: inner plexiform layer, INL: inner nuclear layer, ONL: outer nuclear layer. Scale bar, 50 μm.