Physiological significance of ECL-cell histamine

Area of Science:

• Gastroenterology
• Physiology
• Pharmacology

Background:

• Histamine in the stomach's oxyntic mucosa is stored in enterochromaffin-like (ECL) cells and mast cells.
• ECL cells contain the majority (at least 80%) of histamine in rat oxyntic mucosa.
• Histamine plays a crucial role in regulating gastric acid secretion.

Purpose of the Study:

• To investigate the role of ECL cell histamine in mediating gastric acid secretion.
• To determine if ECL cell histamine is essential for gastrin- and vagally-induced acid secretion.
• To examine whether gastrin's trophic effects on the oxyntic mucosa depend on ECL cell histamine.

Main Methods:

• Depletion of ECL cell histamine using alpha-fluoromethylhistidine (alpha-FMH).
• Measurement of basal, gastrin-stimulated, and vagally-induced gastric acid secretion.
• Induction of long-term hypergastrinemia combined with alpha-FMH infusion.

Main Results:

• Depletion of ECL cell histamine reduced basal acid secretion and abolished gastrin-stimulated secretion.
• Vagally-induced acid secretion was unaffected by alpha-FMH but inhibited by an H2 antagonist.
• Gastrin-evoked trophic effects on the oxyntic mucosa were independent of ECL cell histamine.

Conclusions:

• Gastrin stimulates gastric acid secretion primarily through the release of histamine from ECL cells.
• Vagally-induced acid secretion, while histamine-dependent, does not rely on ECL cell histamine.
• Gastrin's trophic effects on the stomach are independent of ECL cell histamine.