Figure 2  .

Immunohistochemical localisation of neurokinin-1 receptor (NK-1R) protein expression in non-inflamed colon (A, B), in active ulcerative colitis (UC) colon (C, D), and in active Crohn's disease (CD) colon (E, F). Sections are consecutive to those processed for in situ hybridisation in fig 1 and are shown at higher magnification. (A) NK-1R immunoperoxidase staining (brown) is detected in lamina propria mononuclear cells (LPMC), and in surface (top right of figure) and crypt epithelium of normal colon. (C) NK-1R expression (brown) is present in LPMC and in surface epithelium of UC colon. Note the crypt epithelium is negative for NK-1R expression (blue). (E) Expression of NK-1R protein (brown) by LPMC and crypt epithelial cells of CD colon. (B, D, F) Control staining of consecutive sections of normal (B), UC (D), and CD (F) colon. Specificity of antibody binding was confirmed, as preincubation of the primary antibody with the NK-1R immunising peptide inhibited staining. All sections were counterstained with haematoxylin (blue).