In the mictochondria of these mysenteric neutrones ,an enzyme called acetylcoA synthetase and which is expressed on the cells mictochondrial outer membrane condenses the acetic acid that has arrived the membrane with coenzyme A to form acetylCoA . AcetylCoA upon its formation at this stage leaks back into the cytosol of mysenteric neurones where it is condensed again with choline (as a food nutrient usually sourced from the digestion of phospholipids ,specifically phosphatidylcholine as a type of lipid nutrients) by another enzyme called acetylcholine transferase to form acetylcholine!
A neutrotransmitter that has cholinergic cells in the brain as its primary site of production in the body . As if this accidental side pathway of alcohol metabolism to acetylcholine in the gastrointestinal tract during period of beer ingestion on the part of beer drinkers is not enough, it is worst yet unfortunate that the same acetylcholine also accidentally and coincindentally has its receptors on the membrane on the membrane surface of parietal cells as another group of cells on the gastric linnings,that have hydrochloric acid secretion for digestion as their role in gastrophysiology slide_24.jpg[source]
Acetylcholine receptors on the membrane surface of parietal cells are called M2 receptors and they are stimulatory in their effect, and not inhibitory. Therefore, with acetylcholine available at high concentration from alcohol's accidental side metabolism in the gastrointestinal tract of beer drinkers arround the moment of beer ingestion, the acetylcholine binds its M2 receptors on the membrane surface of parietal cells in the stomach such that the cells are stimulated for hydrochloric acid secretion as a basis of an immediate gastric hyperacidity. In normal physiology, a moderate secretion of hydrochloric acid by parietal cells into the stomach chamber activates pepsinogen as an inactive zymogenic form of pepsin to pespin, an enzyme that digests proteins in foods that arrive the stomach after or during a meal.
 for an immediate denaturative and hydrolytic mobilisation and autodigestion by pepsin as a basis of the ulcer being widened and deepened the more, an exacerbation or worsening indeed! Ulcer worsening by beers manifests in victims as strong abdominal pain in the form of heat after beer seep.