Fig. 5
EP2 and EP4 receptor immunoreactivities in the smooth muscle layer of the rat middle colon. Immunoreactivity for the EP2 receptor (a, red) and α smooth muscle actin (α-SMA) (b, green) in cryostat sections (10 µm thick) of rat middle colon was visualized with fluorescence microscopy and an image acquisition system. Merged image of EP2 and α-SMA is shown in c (bar = 50 µm), and a magnified image of the square site is shown in d (bar = 10 µm). Immunoreactivity for the EP4 receptor (e, red) and α-SMA (f, green) was also visualized. Merged image of EP4 and α-SMA is shown in g (bar = 50 µm), and magnified image of square site is shown in h (bar = 10 µm). Arrows indicate EP2 immunoreactivity or EP4 immunoreactivity in myenteric ganglia. Arrowheads indicate EP2 immunoreactivity or EP4 immunoreactivity at interstitial sites in the circular muscle layers. LM, longitudinal muscle; CM, circular muscle; and MG, myenteric ganglion