Figure 4. Expression of P2Y_2,4 in the rat urinary bladder.

(A) P2Y₂ immunoreactivity was present in the bladder urothelium (arrows). (B) Little/no P2Y₄ immunoreactivity was detected in the rat bladder. (C) Background immunofluorescence was assessed in the absence of primary antibodies and secondary only. Colocalization of P2Y₂ receptor with cytokeratin 20 (D-F) and cytokeratin 17 (G-I) revealed P2Y₂ expression in both apical and basal cells of the urothelium. Further colocalization studies with P2Y₂ with PGP9.5 revealed P2Y₂ receptor expression within submucosal nerve fibres (J-L) and nerve bundles (M-O; * denotes localization of the urothelium).