Gastric secretagogues

As a gastric secretagogue, alcohol stimulates the secretion of gastric juice, which is rich in acid and pepsin. Therefore, the consumption of alcohol is contraindicated in subjects with untreated acid-pepsin disease (Figure 68.2). In addition, alcohol releases histamine, which in turn releases gastric juice. This effect is not blocked by atropine. 

Figure 6-10. Simon Komarov s demonstration of the response of an anesthetized cat to an intravenous injection of histamine-free antral mucosal extract and the effect of injection of atropine upon the response. (From Komarov SA. Physiological properties of the specific gastric secretagogue of the pyloric mucous membrane. Rev Can Biol 1 377-387, 1942.)... 

A second important nonneuronal site of histamine storage and release is the enterochromaffin-like (ECL) cells of the fundus of the stomach. ECL cells release histamine, one of the primary gastric acid secretagogues, to activate the acid-producing parietal cells of the mucosa (see Chapter 62). 

The methylxanthines stimulate secretion of both gastric acid and digestive enzymes. However, even decaffeinated coffee has a potent stimulant effect on secretion, which means that the primary secretagogue in coffee is not caffeine. 

Isolation and discovery of ghrelin support another control system for GH release in addition to GH-RH and SRIF. Ghrelin is a small 28 amino acid (AA) peptide released from neuroendocrine cells in the gastric mucosa that binds to the GH secretagogue receptor to induce the secretion of both GH-RH and GH itself. Ghrelin also induces food intake and the development of obesity. 

I]n four experiments so far performed, in which the main fundic pouch was perfused with a solution of secretagogues, a response of free acid was obtained from both this pouch and the transplant. [T]he unmistakable secretion of free acid by both pouches shows that the presence in the main gastric pouch of the pyloric mucosa is not essential for either the local response of the main fundic pouch or the humoral response of the transplant to perfusion of this with a solution of secretagogues. 

Bei lindh T, Helander HF, Obrink KJ. Effects of secretagogues on oxygen consumption, aminopyrine accumulation and morphology in isolated gastric glands. Acta Physiol Scand 1976 97 401. 

Berglindh T (1977) Effects of common inhibitors of gastric acid secretion on secretagogue-induced respiration and aminopyrine accumulation in isolated gastric glands. Biochim Biophys Acta 464 217-233... 

Histamine is a powerful secretagogue, and evokes a rapid flow of gastric juice and saliva when injected into the human subject. 

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