BSS injected control (A), 0.05 µg (B), 0.1 µg of Tunicamycin (C), and NMDA injected mice (D). Eyes were enucleated 2 weeks post injection, and tissue sections examined by H&E staining. The photoreceptor cells loss was dose dependent. In 0.1 µg tunicamycin, nearly 80% of photoreceptors were lost throughout the retina. In contrast, the RGC were minimally affected. The RGC numbers in control and tunicamycin treated groups were similar, while that of NMDA treated eyes was dramatically decreased as shown in histological sections. Scale bars, left panels 100 µm and right panels 50 µm.