Vasoactive intestinal peptide-containing nerves in Peyer's patches.

Vasoactive intestinal peptide (VIP) is a neuropeptide that is well represented in the gut tract. Previous work has demonstrated that murine T lymphocytes have high-affinity specific receptors for VIP and has implicated their interaction with VIP in the control of T-cell migration into Peyer's patches in vivo. It was postulated that this effect was mediated by interactions in the vicinity of the specialized endothelium of the postcapillary venules of Peyer's patches. We report the localization of VIP-like immunoreactivity in mouse Peyer's patches. Immunohistochemical staining was performed with heterologous antiserum against VIP using the avidin-biotin-peroxidase complex technique. VIP positivity was present near vessels of various sizes and in close proximity to small caliber vessels lined with specialized polygonal endothelial cells. These findings provide an anatomical basis for the concept that VIP may be available as a local neurophysiological signal during the migration of lymphocytes from the blood into Peyer's patches.