The distribution of peptidergic (substance P and vasoactive intestinal polypeptide) nervefibres along the walls of blood vessels was examined in feline canine tooth pulps by an indirect immunofluorescence method.
Substance P (SP)-containing nerve fibres were observed in nerve bundles entering into the pulpalong the blood vessels. Only one or two nerve fibres showed SP immunofluorescence in a thick nervebundle. Around the blood vessels in the central pulp, many SP-positive nerve fibres with varicositieswere observed. They showed a network arrangement surrounding the walls of large bloodvessels. Near the odontoblastic layer, some of the small blood vessels were associated with single SPfibres. Not all blood vessels were accompanied by SP nervefibres and not all SP nerve fibres wererunning along the blood vessels.
Vasoactive intestinal polypeptide (VIP)-containing nerve fibres were also observed in apical nervebundles, but the number of VIP nerve fibres was fewer than that of SP nerve fibres. The distributionpattern of VIP nerve fibres surrounding the pulpal blood vessels was very similar to that of SPnerve fibres, but the number of VIP nerve fibres was also fewer than that of SP nerve fibres.