SUBSTANCE-P - AN IMMUNOHISTOCHEMICAL AND BIOCHEMICAL-STUDY IN HUMAN GINGIVAL TISSUES - A ROLE FOR NEUROGENIC INFLAMMATION

SUBSTANCE P HAS BEEN STUDIED in relation to its distribution within gi ngival tissues as well as its effect on cultured human gingival fibrob lasts. The tissue distribution was varied depending on the degree of i nflammation present. In healthy tissues substance P was found in the c onnective tissues interspersed between the collagenous elements and wa s particularly prominent in the areas immediately subjacent to the epi thelial rete pegs. In inflamed tissues, substance P was markedly incre ased particularly around the blood vessels as well as in close associa tion with much of the inflammatory cell infiltrate. The effect of subs tance P on human gingival fibroblast proliferation was monitored by [H -3]-thymidine incorporation and indicated substance P to be mitogenic for these cells at low concentrations (1 X 10(-9) M) and tended toward s an inhibitory effect at higher concentrations (1 X 10(-4) M). Substa nce P did not have any effect on the release of either total proteins or proteoglycans into the culture medium. However, exposure of the cel ls to substance P did cause a greater accumulation of both total prote in and proteoglycan with the cell layer material. These findings sugge st a potential role for substance P on gingival tissues and in particu lar their resident fibroblastic cells and can therefore be used as a b asis for more detailed studies into the relationship between neuropept ide release associated with neurogenic inflammation and periodontal pa thology.