Background/Aims: Short-term psychological stress increases pressure in the upper esophageal sphincter and increases esophageal contraction amplitude. The effects of short-term psychological stress on the two sphincteric mechanisms at the esophagogastric junction (EGJ), the lower esophageal sphincter (LES) and crural diaphragm, were studied. Methods: Studies were performed in 20 normal, healthy subjects. LES and crural diaphragm functions were measured simultaneously using an electrode sleeve sensor. Three psychological stress tasks, math, cold, and stress interview, were tested. The data were analyzed for tonic (end expiratory) and phasic (inspiratory increase) EGJ pressure and electromyographic changes during the stress period. Spontaneous swallow-induced EGJ relaxation was also assessed. Results: A significant decrease in tonic EGJ pressure occurred during the math and cold tasks. The tonic EGJ pressure was 19 ± 2 and 14 ± 2 during baseline and the math task, respectively. Stress caused no change in the phasic EGJ pressures. Tonic and phasic crural diaphragm electromyographic activity increased during all three stress periods. Spontaneous swallow-induced relaxation at the EGJ during the stress periods was reduced from 60% ± 2% in the baseline to 39% ± 5% during the stress periods. Conclusions: Short-term psychological stress lowers EGJ pressure through inhibition of the LES and increases tonic and phasic crural diaphragmatic contraction. Diminished swallow-induced relaxation at the EGJ during stress may lead to changes in esophageal contractions.
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