Nerve fibres displaying such immunoreactivity were revealed by indirect immunofluorescence. Neuropeptide K-like immunoreactive fibres, entering the pulp within large nerve trunks, were distributed around blood vessels as well as in the stroma. Some immunoreactive fibres were also observed in the para-odontoblastic region. In view of the biological activity of neuropeptide K, it is tentatively proposed that it may act in the dental pulp as a regulatory peptide involved in neurogenic inflammation, blood flow regulation and sensory transmission.