A comparison of four extraction methods for substance P, neurokinin A and calcitonin gene-related peptide from human dental pulp tissue

Measuring neuropeptides in biological tissues by radioimmunoassay requires efficient extraction that maintains their immunoreactivity. Many different methods for extraction have been described, but there is little information on optimal extraction methods for individual neuropeptides from human dent al pulp tissue. The aim was therefore to identify an effective extraction p rocedure for three pulpal neuropeptides: substance P. neurokinin A and calc itonin gene-related peptide. Tissue was obtained from 20 pulps taken from t eeth freshly extracted for orthodontic reasons. The pulp samples were divid ed into four equal groups and different extraction methods were used for ea ch group. Boiling whole pulp in acetic acid gave the highest overall yield and, in addition, offered an easy and rapid means of pulp tissue processing . The use of protease inhibitors did not increase the recovery of the immun oreactive neuropeptides but did provide the best combination of maximal rec overies and minimal variability. These results should be useful for plannin g the extraction of these neuropeptides from human pulp tissue in future st udies. (C) 1999 Elsevier Science Ltd. All rights reserved.