Localization, density and shape of serotonin - and chromogranin a-positive neuroendocrine cells in feline bulbourethral glands

Abstract

The current study aimed to investigate the presence, type and localization of endocrinocytes containing serotonin and chromogranin A (NE) in feline bulbourethral glands and their role in the functioning of those organs. Bulbourethral glands of 8 sexually mature, clinically healthy male European shorthair cats (Felis catus) aged 1−2 years and weighing 2.8−4 kg were studied. Collected specimens were processed by routine techniques and embedded in paraffin. Immunohistochemical assay was carried out with primary antibodies against human serotonin and chromogranin A using the avidin-biotin peroxidase technique. Neuroendocrine cells (NE) were mainly observed in the tubular epithelium. In the glandular stroma, only single serotonin-positive endocrinocytes (SNE) were found. The density of serotonin-expressing endocrinocytes was higher than that of chromogranin A-expressing cells (ChNE), while the latter were larger and of a various shape than the former. The morphology of studied neuroendocrine cells was of both open-type and closed-type. We propose that neuroendocrine cells in feline bulbourethral glands were involved in the protection of glandular epithelial cells, in homeostatic regulation of glands‘ secretion and semen and urinary excretion.