Session 4: Histamine-Producing Cells in the Stomach and Their Role in the Regulation of Acid Secretion

Abstract

Håkanson R, Sundler F. Histamine-producing cells in the stomach and their role in the regulation of acid secretion. Scand J Gastroenterol 1991, 26(suppl NO), 88–94

Histamine H₂-receptor antagonists inhibit basal and all kinds of stimulated acid secretion with about the same effectiveness. and hence, local release of histamine is thought to be necessary for the stimulation of parietal cells. A local histamine pool is physiologically relevant only if it is within the diffusion distance of the parietal cells, if it is effectively mobilized by gastrin, and if it is endowed with the machinery for a rapid replenishment of the histamine that has been released. Histamine in the stomach occurs in endocrine cells (so-called enterochromaffin-like (ECL) cells), mast cells, and neurons. The ECL cells are peptide hormone-producing cells. In mommals they are located basally in the oxyntic gland area, in the chief-cell-rich region. Parietal cells predominate in the mid-region. ECL cells respond readily to gastrin with histamine release and histamine resynthesis. Thus, the ECL cells fulfil important prerequisites of a physiologically relevant histamine pool. However, it is not apparent how the preferential localization of ECL cells at the base of the glands may be conducive to a direct effect of released histamine on the parietal cells, unless histamine reaches the parietal cells via capillary transport from the glandular base. Mast cells are numerous in the stomach of, for example, man, pigs, dogs, and cats. They occur scattered throughout the stomach wall without any obvious relation to the parietal cells. There is no evidence that gastrin mobilizes histamine from these cells. His-tamine-containing neurons, finally, might represent an alternative source of physiologically relevant histamine. Histamine-immunoreactive neurons and a few immunoreactive fibers have been observed in the myenteric plexus of the stomach wall. Histamine-containing fibers have not been detected in the gastric mucosa, which makes it unlikely that neuronal histamine could be directly responsible for activating the parietal cells.

Key Words:

• Acid secretion
• enteric nervous system
• enterochromaffin-like cells
• histamine
• histaminergic
• mast cells
• neurons