Duodenal motor effects of simulated mastication

Abstract

Seven adult female rats fasted 24 h. Under pentobarbital duodenal movements were observed for three consecutive five minute periods: baseline, procedure, and postprocedure. No gauges or tubes were used. The procedure simulated chewing by raising and lowering the jaw every s for 300 s to transiently achieve molar contacts. Duodenal segmentations (mean ± s.d.) per 5 min are tabulated. Analysis: ANOVA,with Bonferroni for pair analysis. Teeth are suspended in their sockets by a periodontal ligament about each root. These supports have many mechanoreceptors (PDLMs), activated by teeth contact in chewing (Lund Exp Brain Res 19:, 1974; Johnsen J Neurophysiol 89:, 2003) or in simulated mastication. In these fasted rats their heightened motor activity indicates a periodontoduodenal motility reflex. By its PDLM-dependence this reflex resembles the periodontogastric motility (Lorber Can J Physiol Pharmacol 78:, 2000) and emptying reflexes (Lorber J Dent Res 81:, 2002). In the latter it made no difference whether fed edentulous people, lacking PDLMs, wore their dentures or not (Poitras Digestion 56:, 1995); but fed dentate subjects emptied faster when they chewed rapidly (Pera J Dent Res 81:, 2002). Thus, PDLM presence is vital for all of these reflexes. Support: Personal