Neuroendocrine cells in the cat laryngeal epithelium.

The structure and distribution of neuroendocrine cells in the feline laryngeal epithelium were examined using immunohistochemical techniques. Neuroendocrine cells were often spindle shaped, with cytoplasmic processes directed towards the lumen and basement membrane. The apical portion of the cells usually reached the laryngeal lumen with microvillous projections. The cytoplasm always contained variable numbers of electrondense cored vesicles. The number of neuroendocrine cells decreased in the following order: subglottis, posterior glottis, supraglottis, anterior glottis. Neuroendocrine cells contained calcitonin gene-related 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 the regulatory function of the cat larynx by releasing various peptides. These substances may contribute to allergic reactions or control mucus secretion by acting via the endocrine or paracrine pathways and/or neurosecretory pathways.