The G-cells in the dog: a light and electron microscope immunocytochemical study

Area of Science:

• Gastroenterology
• Cell Biology
• Histology

Background:

• Gastrin cells (G-cells) play a crucial role in regulating gastric acid secretion.
• Understanding the precise distribution of G-cells in the canine gastrointestinal tract is essential for comparative physiology and pathology.

Purpose of the Study:

• To investigate the distribution and ultrastructural characteristics of gastrin-producing G-cells in the canine gastrointestinal tract.
• To examine the influence of fixation pH on gastrin immunodetection in G-cells.

Main Methods:

• Immunohistochemistry was employed to identify gastrin-immunoreactive cells.
• Ultrastructural analysis using electron microscopy was performed on G-cells.
• The effect of varying pH levels during fixation on G-cell granule morphology and gastrin staining was assessed.

Main Results:

• Gastrin G-cells were predominantly found in the pyloric antral mucosa of dogs, with a density of 8.5 x 10^3–1.2 x 10^4 cells cm^-2.
• A small population of G-cells was observed in the proximal duodenum.
• The fundic stomach, esophagus, intestines, and accessory organs were devoid of gastrin-immunoreactivity.
• Ultrastructurally, G-cells contained granules of varying electron density, influenced by fixation pH.
• Acidic fixation enhanced gastrin staining in electron-dense granules, while basic fixation dispersed gastrin into the cytoplasm.

Conclusions:

• The pyloric antrum is the primary reservoir of gastrin G-cells in dogs.
• Fixation pH significantly impacts the localization and detection of gastrin within G-cells, highlighting the importance of optimized protocols for accurate immunohistochemical analysis.