Immunocytochemical and ultrastructural characterization of endocrine cells in chicken proventriculus

Area of Science:

• Endocrinology
• Gastroenterology
• Cell Biology

Background:

• The chicken proventriculus is a key digestive organ.
• Understanding its endocrine cell populations is crucial for avian physiology.
• Previous research has not fully characterized all endocrine cell types and their localizations.

Purpose of the Study:

• To comprehensively investigate and identify the endocrine cell types within the chicken proventriculus.
• To describe the ultrastructure of specific cell types, including newly identified ones.
• To determine the colocalization of specific peptides within these endocrine cells.

Main Methods:

• Immunocytochemistry using peroxidase-antiperoxidase (PAP) technique for light microscopy.
• Immunogold staining on osmium-fixed material for electron microscopy.
• Testing of twenty-three different antisera to identify cell markers.

Main Results:

• Identification of seven distinct immunoreactive cell types: D-cells (somatostatin), EG-cells (glucagon, GLP1, neurotensin), NT-cells (neurotensin), BN-cells (bombesin), ENK-cells (met-enkephalin), EC-cells (serotonin), and APP-cells (avian pancreatic polypeptide).
• Electron microscopy confirmed the ultrastructure of all identified cell types, including enterochromaffin-like (ECL) cells.
• The presence and ultrastructure of ENK-cells and NT-cells were described for the first time in chicken proventriculus.
• Colocalization of glucagon, GLP1, and neurotensin was demonstrated in EG-cells.

Conclusions:

• The chicken proventriculus harbors a diverse array of endocrine cells with distinct peptide expressions.
• This study provides the first detailed ultrastructural and immunocytochemical characterization of ENK-cells and NT-cells in this organ.
• The colocalization of glucagon, GLP1, and neurotensin in EG-cells suggests complex regulatory roles in avian digestion.