Abstract
The sensory neuropeptides substance P and calcitonin gene-related peptide have been implicated in the mediation of pulpal inflammation. A possible role in healing following injury has also been suggested (Byers et al., 1990). This possibility has been investigated by an examination of a direct effect of substance P and calcitonin gene-related peptide in vitro on fibroblast-like cells derived from human dental pulp. Cells were cultured for 48 hr in Dulbecco's modified Eagle medium plus 20% fetal calf serum and antibiotics. Substance P and calcitonin gene-related peptide were added in the range from 10-12 to 10-4 mol/L. Fibroblast growth factor was used as a positive control. Effects on cell proliferation were assessed by cell counts (daily for 6 days) and [3H]-thymidine uptake (24 hr after the addition of peptides). An effect on cellular functional activity was measured by [35S]-sulfate incorporation into glycosaminoglycans, in confluent cell cultures. Both substance P and calcitonin gene-related peptide showed concentration-dependent stimulation of cell proliferation. The maximum stimulation of approximately 40% was achieved at substance P and calcitonin gene-related peptide concentrations of 10-6 mol/L, comparable with stimulation by fibroblast growth factor. By contrast, little increase in glycosaminoglycan synthesis by confluent cells could be detected. The direct effect on pulp cells is consistent with a role of the neuropeptides in pulp healing. This is exerted at the level of cell proliferation, rather than functional activity.
Get full access to this article
View all access options for this article.