NEUROENDOCRINE CELLS IN THE CAT LARYNGEAL EPITHELIUM

The structure and distribution of neuroendocrine cells in the feline l aryngeal epithelium were examined using immunohistochemical techniques . Neuroendocrine cells were often spindle shaped, with cytoplasmic pro cesses directed towards the lumen and basement membrane. The apical po rtion of the cells usually reached the laryngeal lumen with microvillo us projections. The cytoplasm always contained variable numbers of ele ctron-dense cored vesicles. The number of neuroendocrine cells decreas ed in the following order: subglottis, posterior glottis, supraglottis , anterior glottis. Neuroendocrine cells contained calcitonin gene-rel ated peptide, substance P and/or 5-hydroxytryptamine. They also showed protein gene product 9.5 or neuron-specific enolase immunoreactivity. These observations suggest that neuroendocrine cells play a part in t he regulatory function of the cat larynx by releasing various peptides . These substances may contribute to allergic reactions or control muc us secretion by acting via the endocrine or paracrine pathways and/or neurosecretory pathways.