ALTERATIONS IN BUCCAL MUCOSAL ENDOTHELIN-1 AND NITRIC-OXIDE SYNTHASE WITH CHRONIC ALCOHOL INGESTION

Endothelin-1 (ET-1) and nitric oxide are emerging key mediators in the maintenance of mucosal homeostasis, but little is known about these s ubstances in soft oral tissue with alcohol abuse. Hence, we examined t he expression of ET-1 and activity of the constitutive nitric oxide sy nthase (NOS) in buccal mucosa of rats subjected to chronic ethanol die t. The immunometric assays revealed the buccal mucosal level of ET-1 i n the controls at 40.2 pg/mg protein and showed a 4.1-fold increase wi th alcohol diet to 166.2 pg/mg protein. The NOS assays established tha t comparing to the controls, the alcohol diet group exhibited a 57% de crease in buccal mucosal NOS activity. Moreover, the expression of ET- 1 showed an inverse correlation (r = -0.75) with the extent of the ind uced changes in NOS. The results suggest that an increase in vasoconst rictive ET-1 levels combined with a loss of compensatory action by the constitutive NOS may be responsible for the weakening of oral mucosal defenses in alcoholics.