Figure 2: Immunohistochemical labelling for substance P and calcitonin gene-related peptide. Cresyl violet staining showed the different laminae of the gray matter of the cervical region of the spinal cord (top panel). Location of the box showed the area of interest (Laminae I-II). Expression of both substance P and calcitonin gene.related peptide was noted over the superficial laminae (I-I). Increased expression of substance P was present in the morphine + fosaprepitant treated group. Each group had 6 animals