MORPHOLOGIC STUDY OF THE LARYNGEAL TASTE-BUDS IN THE CAT

The distribution of laryngeal taste buds (TBs) and their neural compon ents in the cat were investigated by immunohistochemistry and electron microscopy. The antisera used in this study were against cytokeratin, protein gene product 9.5 (PGP9.5), neuron-specific enolase (NSE), S-1 00 protein calbindin-D, calcitonin gene-related peptide (CGRP), and su bstance P (SP). Taste bud cells were specifically immunoreactive to th e antibodies of human cytokeratin subtypes 8 and 18 (CAM5.2). On obser vation with CAM5.2, TBs were seen distributed on the laryngeal surface of the epiglottis and spread caudally along the aryepiglottic folds, reaching peak density at the laryngeal side of the arytenoid tubercle. The PGP9.5 and NSE immunoreactivities were recognized in TB cells and nerve fibers, both within the TBs and in the subepithelial connective tissue. S-100 protein immunoreactivities were not found in any of the cells in the TBs but were found exclusively in the subepithelial neur al elements. The calbindin-D, CGRP, and SP immunoreactivities were con fined to a part of the neural elements that was very thin. Taste pores , taste villi, neuronal varicosity, and synapselike structures were ob served by scanning and transmission electron microscopic study. From t hese results it is considered that the TBs act as a chemical receptor.