Integrated Histological, Ultrastructural, and Immunohistochemical Characterization of Gastric Regions in the Domestic Cat, Felis catus
DOI:
https://doi.org/10.48165/ijapm.2026.42.00.21Keywords:
stomach, histology, scanning electron microscopy, neuroendocrine cellsAbstract
Background: The gastric mucosa of the domestic cat (Felis catus) demonstrates notable specialization associated with its carnivorous physiology, yet there are still few investigations integrating morphological, ultrastructural, and neuroendocrine features. This paper presents a detailed description of gastric morphology and function in adult domestic cats, focusing on the relationships between ultrastructural architecture and Chromogranin A-positive cell distribution. Aim of study: As there are very limited investigations on this species and it is one of the most common domestic carnivorous pets in Iraq, this study aims to characterize the gastric regions of adult domestic cats. Methods: Fourteen adult domestic cats of both sexes were examined. Histological and immunohistochemical examinations of tissue samples were conducted for three main gastric regions using histology staining and Chromogranin A immunolabeling in seven cats. In another seven cats, samples were studied with SEM to reveal the ultrastructural characteristics. A semi-quantitative evaluation based on visual assessment of Chromogranin A-positive cell density was used to assess regional specificity. Result: It was shown that gastric mucosa in different regions had different mucosal thickness and different organization and composition of glands. Thus, mucosa in the cardiac region showed prominent mucous glands, while the fundic region contained well-developed tubular glands with an abundance of chief and parietal cells, indicating the important role of this region in enzymatic and acid secretions. The pyloric region demonstrated deep gastric pits, rich mucous glands, and a thick muscularis externa layer, which indicates high functional activity. Scanning electron microscopy of the fundic region revealed a characteristic honeycomb-like structure of gastric pits, while surfaces in the other two regions demonstrated lesser organization. Immunohistochemical analysis showed a predominance of Chromogranin A-positive cells in the fundic region, a smaller quantity in the cardiac region, and an absence or rarity of them in the pyloric region. Conclusion: The feline stomach shows considerable regional differences in morphology, ultrastructure, and neuroendocrine specialization. There is considerable variation in glandular arrangement, surface morphology, and presence of Chromogranin A positive cells in the fundus. These characteristics set up a functional basis that is essential for digestive function in the domestic cat and form a standard for comparison in other carnivores.
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