Fig 1: Whole mounts of urinary bladder tissue were prepared at the urothelial-lamina junction and contained a dense network of capillaries, small blood vessels and cells from rat pups aged ≤ P21. Capillaries, blood vessels and cells were loaded with the fluorescent dye (Fluo-2, green) (A,B,E). Tetramethylrhodamine (TRITC; red) was picked up by urothelial cells and provided contrast to Fluo-2 loaded cells (A,B). The cellular network in the lamina propria was heterogeneous with numerous small round, stellate or spindle shaped cells (10–20 μm) with multiple processes projecting from the soma in rat pups aged P ≤ 21. Numerous cells in the lamina propria exhibited PDGFRα-immunoreactivity (IR) whereas fewer cells exhibited TRPV4-IR (C,D). At the urothelial-lamina propria junction, a dense capillary network was in close proximity to the network of cells expressing PDGFRα- and TRPV4-IR (E). Capillaries were isolated using their signature, long tubular shape in the PTCL analysis software and recolored red to distinguish them from lamina propria cells. 3-D images of the capillary network and the lamina propria cell network at different angles of rotation (E,i,ii). Calibration bar in (B) represents 10 μm (A,B), 15 μm (C,D). Calibration bar in (E) represents 5 μm.