J0203-1-1 Relationship between masseter muscle pain and its edematous changes

Abstract

To clarify the relationship between masseter muscle pain and its edematous changes, we investigated whether increased in thickness and plasma extravasation may occur in the rat masseter muscle as a result of capsaicin injection. In anaesthetized rat, capsaicin solution was injected into a masseter muscle on the one side, and vehicle into one on the other side. The thickness of the masseter muscle was measured by means of high-frequency ultrasound. Plasma extravasation was determined by means of the Evans blue dye method. As results, capsaicin injection into the masseter muscle induced thickening and plasma extravasation in the masseter muscle, and combination with local anaestesia counteracted the dye extravasation, indicating neurogenic inflammation change in rat masseter muscle.