Vagal stimulation is associated with which peptide?

Vagal stimulation is primarily associated with the release of acetylcholine, which is a key neurotransmitter used by the vagus nerve to communicate with various organs, especially in the digestive system. This activation promotes several digestive processes, including increasing gastric motility and stimulating the secretion of gastric juices.

However, gastrin-releasing peptide (GRP) plays a specific role in the context of vagal stimulation. GRP is released from the vagus nerve fibers when they stimulate G cells in the stomach. This release of GRP subsequently stimulates the G cells to secrete gastrin, which further enhances gastric acid secretion and promotes digestive activity.

While other peptides like cholecystokinin and secretin play important roles in digestion, they are not directly associated with vagal stimulation. Cholecystokinin is primarily involved in digestion by stimulating bile release and pancreatic enzyme secretion in response to fatty acids and amino acids. Secretin is released in response to acidic chyme entering the duodenum and helps regulate the pH by stimulating bicarbonate secretion from the pancreas. Thus, while they are important hormones, they do not have the same direct relationship with vagal stimulation as gastrin-releasing peptide does.