Immunolabelling of neuropeptide Y in blood vessels and ductal epithelium in the submandibular glands. Immunostaining with anti-neuropeptide Y (anti-NPY) antibody in sections from (a), (b), (d) nonobese diabetic (NOD) submandibular gland and (c) BALB/c submandibular gland (Taconic Bomholtgård mice, Group 1). Scale bars = 50 μm. (a) Numerous NPY-immunoreactive (IR) fibres (arrowheads) in walls of blood vessels in areas with focal mononuclear cell inflammation. (b) Immunoreactivity (arrowheads) in the wall of a blood vessel and a duct surrounded by a focus of infiltrating mononuclear cells. (c) Ductal cells showing intracellular NPY staining (arrowheads), whereas acini cells are without staining and lack innervation of NPY-IR fibres. (d) Typical localization of a vessel with a network of NPY-IR fibres in close proximity to a large duct (D) and a focus of infiltrating cells. a, acini; d, duct; f, focal mononuclear cell inflammation; v, vessel.