Local Opioids in the Inflamed Dental Pulp

We have looked for the presence of β-endorphin and somatostatin in normal and inflamed pulps. In 25 adult rats, under anesthesia, small openings were made into the pulp on the mesial surface of both first molars on one side. One week later all four first molars were removed, half were processed for immunohistochemistry using specific antibodies to β-endorphin, somatostatin, and CD3, a marker for T lymphocytes. The pulps of the remainder were removed, solubilized, and subjected to enzyme-linked immunosorbent assay for somatostatin and β-endorphin. Many cells that labeled for β-endorphin and somatostatin in the injured pulps also stained for CD3. The levels of both β-endorphin and somatostatin, were higher in the exposed than in the uninjured pulps (t test, p < 0.05). β-endorphin and somatostatin are both produced in increased amounts in the dental pulp during inflammation attributable, at least in part, to the presence of T lymphocytes producing these substances.