Representative images following denervation at the level of the superior mesenteric artery (SMA). A: Distal duodenum (internal positive control). B: Ileum following denervation at the SMA .This figure shows a representative whole mount preparation of terminal ileum from an animal that had undergone denervation at the level of the superior mesenteric artery (SMA). Stainings were performed for tyrosine hydroxylase which is present on sympathetic nerve fibers. Note the absence of tyrosine hydroxylase positive fibers in ileum of denervated animals showing lack of sympathetic innervation (B) compared to the normal distribution of sympathetic fibers in the distal duodenum which served as internal positive control (A).