Histological staining of penis sections from adult TR4+/+mice, and TR4-/- mice both with and without priapism. Penile cross sections are compared after Accustain Masson Trichrome (Sigma-Aldrich) staining. Each of panels G-I show a region of the corpus cavernosum from the sample indicated. DV, dorsal vein; DA, dorsal artery; CC, corpus cavernosum; CS, corpus spongiosum; N, nerve bundle; U, urethra. Scale is the same for all images in each row. For images A-C, scale bar = 250 μm; D-F, scale bar = 50 μm; G-I, scale bar = 50 μm; J-L, scale bar = 50 μm.