Neuropeptide Y: occurrence and distribution in dental pulps

Nerve fibers displaying neuropeptide Y (NPY) immunoreactivity were seen in the dental pulp of several mammals, including man. Generally, the NPY fibers were more numerous in the apical part than in the coronal part and were distributed around small blood vessels and as single fibers in the pulpal stroma. Sequential staining with antibodies against the enzyme dopamine-beta-hydroxylase (DBH), a marker for adrenergic neurons, and NPY showed that DBH and NPY were located in the same perivascular nerve fibers. Further, since chemical and surgical sympathectomy caused the disappearance of pulpal NPY fibers, it is conceivable that NPY fibers in the dental pulp are identical with adrenergic ones. There is thus a morphological basis for suggesting that NPY and noradrenaline cooperate in regulating pulpal blood flow.