Lipopolysaccharide stimulates histamine-forming enzyme (histidine decarboxylase) activity in murine dental pulp and gingiva

Abstract The activities of the histamine-forming enzyme, histidine decarboxylase (HDC), were measured in the dental pulp, gingiva, ear skin and liver in mice, following an intravenous injection of lipopolysaccharide (LPS). LPS induced a remarkable increase in the HDC activity in the dental pulp and the gingiva. These results suggest that the newly formed histamine produced by the induced HDC could be involved in formation of pulpitis or gingivitis (periodontits).