Pulpal Neuropeptide Y levels in relation to pain experience

Neuropeptide Y is a 36 amino acid peptide that belongs to the pancreatic polypeptide family. It co-localises with adrenaline in sympathetic nerves and is released upon sympathetic activation resulting in vasoconstriction. In addition to its vascular effects NPY is also thought to have a role in pain modulation, angiogenesis and immunomodulation. Objectives: The aim of this study was to quantify the levels of NPY in human dental pulp tissue from intact and grossly carious teeth and to relate these results to pain experience. Methods: A total of 48 permanent teeth [mean age 32.1(+/- 11.2 years)] were included in the study, of these 22 were intact and 26 were grossly carious. In the grossly carious group, 17 teeth were reported painful prior to extraction and the remainder were reported non-painful. NPY was measured using a sensitive and specific radioimmunoassay which has been previously described. Pain was scored as either present or absent in all the teeth studied. Results: Of particular interest in this study was the finding that NPY levels were significantly higher in dental pulp tissue from non-painful grossly carious teeth (p= 0.006) compared with painful grossly carious teeth. Conclusions: The increased levels of NPY reported in non-painful grossly carious teeth may suggest a role for NPY in pain modulation in human dental pulp.