Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
Current evidence suggests that there are three sphincters that regulate the flow of chyme from stomach to the duodenum. We investigated the hypothesis whether a fourth 'physiologic sphincter' exists at the duodeno-jejunal junction. The pressure response of the jejunum, duodeno-jejunal junction and duodenum to individual balloon distension of the jejunum and duodenum was recorded in 28 healthy subjected before and after anesthesizing the jejunum, duodeno-jejunal junction and duodenum. The duodeno-jejunal junction length was measured by the station pull-through technique. Duodenal balloon distension with 2 and 4 ml of normal saline did not change the pressures in the duodenum, duodeno-jejunal junction or jejunum (p>0.05). Distension with 6 ml saline produced an increase of duodenum pressure (p<0.01), a decrease of duodeno-jejunal junction pressure (p<0.01), and no change in the pressure of the jejunum (p>0.05), the balloon was expelled to the jejunum. Eight, and 10 ml duodenum balloon distension produced pressure changes similar to those of the 6 ml distension (p>0.05). Jejunum balloon distension with 2 and 4 ml saline induced no jejunum, duodeno-jejunal junction or duodenum pressure changes (p>0.05). Six ml balloon distension effected increase of jejunum (p<0.01) and duodeno-jejunal junction (p<0.05) pressure, but no duodenum pressure changes (p>0.05). Jejunum balloon distension with volumes more than 6 ml produced pressure changes similar to the 6 ml distension. Distension of the anesthetized duodenum, duodeno-jejunal junction or jejunum did not change the duodeno-jejunal junction pressure. A high pressure zone of 1.6±0.04cm length was detected at the duodeno-jejunal junction. Together, the findings show that a high pressure zone exists at the duodeno-jejunal junction suggesting that this region might act as a physiological sphincter.