Quantitative analysis of substance P, neurokinin A and calcitonin gene-related peptide in pulp tissue from painful and healthy human teeth

Aim The purpose of this study was to investigate the levels of substance P (SP), neurokinin A (NKA) and calcitonin gene‐related peptide (CGRP) in painful and healthy human dental pulps. Methodology Forty‐six samples of pulp tissue were collected from extracted or endodontically treated painful teeth and 20 from clinically healthy teeth extracted for orthodontic reasons. All pulp samples were boiled in 0.5 m acetic acid for 10 min, centrifuged and the supernatant collected. SP, NKA and CGRP levels were measured using radioimmunoassay. Results Substance P and CGRP were present in all samples and NKA was detected in 96% of the pulps. CGRP was present in much higher concentrations than SP and NKA in both painful and non‐painful teeth. The painful teeth had significantly higher concentrations of SP (P = 0.02), NKA (P