Changes in duodenal motility produced by noxious mechanical stimulation of the skin in rats.

Three major pressure components were recorded in the duodenum of anesthetized rats by the balloon method: (1) small, fast, rhythmic waves which corresponded to the pendular movement of the duodenum; (2) large, slow, rhythmic waves which corresponded to the peristaltic movement; (3) the baseline component of the pressure. Noxious stimulation was applied to the skin of the neck, chest and abdomen, but only abdominal stimulation produced changes in duodenal pressure. The following three reflexes were observed whose efferent pathways were proven to be through sympathetic nerves and whose major pathway was apparently propriospinal: (1) a decrease in the amplitude of the small, fast, rhythmic waves; (2) a decrease in frequency of the large, slow, rhythmic waves; (3) a decrease in baseline of duodenal pressure.