The periodontoduodenal motility reflex in fed rats

Abstract

Ten female rats were allowed to feed until pausing. They fed for 7±4 min, taking in 1.52±0.81 g of chow. Under pentobarbital three sequential five min periods of visual observations of the proximal duodenum were made. No instrumentation was used. The baseline began at quiescence 168±129 min after feeding. Simulated mastication involved lowering and raising the jaw until opposing molars contacted transiently at a rate of 3/s for 12s followed by a 3s rest. This was repeated for five min followed by postprocedure observations. Segmentations (mean±SD) at baseline were 19.2±17.5. Procedure values were 38.4±48.5. Postprocedure ones were 85.7±82.7. ANOVA 0.038 and Bonferroni for the first and last periods was P < 0.05. These results reflect that tooth contacts cause the periodontal ligament (PDL) about each dental root to distort as the roots intrude deeper into their sockets. This stimulates PDL mechanoreceptors, Vth nerve afferents, whose axons enter the Gasserian ganglion. The latter's somata course to the NTS where contact is made with dendrites from the dorsal motor nucleus of X. These synapses plus vagal innervation underlie the periodontogastric motility (Lorber Can J Physiol Pharmacol 78:29, 2000) and emptying (Lorber J Dent Res 81:302, 2002) reflexes, and the present one. Personal support.