How is physiology of esophagus LES?

• III. Lower esophageal sphincter (LES): This 3–5-cm high-pressure zone at the esophageal lower portion functions to prevent gastroesophageal reflux (GER). No distinct sphincter muscle exists in this area, but manometry readily demonstrates the physiologic high-pressure zone. LES pressure is influenced by several actors and substances. • LES pressure increase: occurs with a protein meal, stomach alkalinization, gastrin, vasopressin, and cholinergic drugs • LES pressure decrease: occurs with secretin, nitroglycerine, glucagon, chocolate, fatty meals, and gastric acidification