Enterochromaffin-like cell

Enterochromaffin-like cells or ECL cells are a type of neuroendocrine cells found in the gastric glands of the gastric mucosa beneath the epithelium, in particular in the vicinity of parietal cells. They are also considered a type of enteroendocrine cell.

Function
ECL cells synthesize and secrete histamine. These cells are stimulated by the hormones gastrin and pituitary adenylyl cyclase-activating peptide. G cells are stimulated by vagal stimulation through the neurotransmitter gastrin-releasing peptide; this causes the G cells to secrete gastrin, which in turn stimulates ECL cells to release histamine. Note that this circuit is not activated by acetylcholine, which is of particular importance because the administration of atropine will not block the vagal stimulation of the G cells, as ACh is not the neurotransmitter for these cells.

Gastrin is transferred from a specific type of G cell in the gastric epithelium to the ECL cells by blood. Histamine and gastrin act synergistically as the most important stimulators of hydrochloric acid secretion from parietal cells and stimulators of secretion of pepsinogen from chief cells. The most important inhibitor of the ECL cell is somatostatin from oxyntic D cells.

Enterochromaffin-like cells also produce pancreastatin and probably other peptide hormones and growth factors.

Pathology
A prolonged stimulation of these cells causes their hyperplasia. This is especially important in gastrinoma (the tumors in which there is an excessive secretion of gastrin), as this is one of the factors contributing to Zollinger-Ellison's syndrome. It was once believed that tumors of ECL origin form after a prolonged inhibition of gastric acid secretion, however there is no data to support this conclusion and proton pump inhibitors are not thought to contribute to gastric cancer.

Name
The name is derived from their location in the enteric system and their chromaffin-like staining pattern in histologic sections, which is characterized by silver staining.