Local electrical stimulation: Effective needling points for suppressing jaw opening reflex in rat

Abstract

Effects of electroacupuncture on the jaw opening reflex after tooth pulp stimulation were investigated in lightly anesthetized rats. Electroacupuncture stimulation (45 Hz, 5 ms) was delivered to 8 meridian points and 6 nonmeridian points for 15 min to compare the degree of suppression elicited from each point. Significant suppressive effects on the reflex were observed in the cases of Yin-Hsiang, Ho-Ku and Shou-Sanli stimulation. These effects were antagonized by naloxone. Stimulation of Hsia-Kuan, ChuCnih, Neiting and Taichi, although these points were reported to suppress oro-facial or dental pain in man, scarcely produced suppressive effects. Stimulation of some nonmeridian points produced moderate analgesic effects as gauged by the jaw opening reflex. Specificity of the meridian points apparently is not absolute but relative, and Yin-Hsiang, Ho-Ku and Shou-Sanli points are fairly effective in suppressing pulp-evoked jaw opening reflex in rat, which is presumably a noxious reflex. When the jaw opening reflex was evoked by non-pulpal stimulation, electroacupuncture was less effective on the reflex.