Identification and characterization of a specific sensory epithelium in the rat larynx.
A specific laryngeal sensory epithelium (SLSE), which includes arrays of solitary chemoreceptor cells, is described in the supraglottic region of the rat. Two plates of SLSE were found, one on each side of the larynx. The first plate was located in the ventrolateral wall of the larynx, and the second was located in the interarytenoidal region. In SLSE, immunoblotting showed the presence of alpha-gustducin and phospholipase C beta2 (PLCbeta2), which are two markers of chemoreceptor cells. At immunocytochemistry, laryngeal immunoreactivity for alpha-gustducin was localized mainly in solitary chemosensory cells. Double-label immunocytochemistry using confocal microscopy demonstrated that alpha-gustducin-expressing cells in large part colocalize type III IP3 receptor (IP3R3), another key molecule in bitter taste perception. However, some IP3R3-expressing cells do not colocalize alpha-gustducin. At ultrastructural immunocytochemistry, these cells showed packed apical microvilli, clear cytoplasmic vesicles, and cytoneural junctions. SLSE was characterized by high permeability to a tracer due to poorly developed junctional contacts between superficial cells. Junctions were short in length and showed little contact with the terminal web. Ultrastructural analysis showed deep pits among the superficial cells. In SLSE, high density of intraepithelial nerve fibers was found. The lamina propria of the SLSE appeared thicker than that in other supraglottic regions. It was characterized by the presence of a well-developed subepithelial nerve plexus. The immunocytochemical and ultrastructural data suggested that SLSE is a chemoreceptor located in an optimal position for detecting substances entering the larynx from the pharynx or the trachea.
Sbarbati
Andrea
A
Department of Morphological-Biomedical Sciences, Human Anatomy and Histology Section, University of Verona, 37134 Verona, Italy. andrea.sbarbati@univr.it
Merigo
Flavia
F
Benati
Donatella
D
Tizzano
Marco
M
Bernardi
Paolo
P
Crescimanno
Caterina
C
Osculati
Francesco
F
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000502:physiology; D002628:Chemoreceptor Cells / Q000378:metabolism / Q000648:ultrastructure; D004847:Epithelial Cells / Q000378:metabolism / Q000648:ultrastructure*; D005260:Female; D007150:Immunohistochemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007365:Intercellular Junctions / Q000378:metabolism / Q000648:ultrastructure; D007527:Isoenzymes / Q000378:metabolism; D007820:Laryngeal Mucosa / Q000294:innervation* / Q000378:metabolism / Q000648:ultrastructure*; D007823:Laryngeal Nerves / Q000378:metabolism / Q000648:ultrastructure*; D007830:Larynx / Q000502:physiology / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D008871:Microvilli / Q000378:metabolism / Q000648:ultrastructure; D054799:Phospholipase C beta; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism / Q000648:ultrastructure; D011984:Sensory Receptor Cells / Q000196:embryology / Q000648:ultrastructure*; D013649:Taste / Q000502:physiology; D015293:Transducin / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes; D018160:Receptors, Cytoplasmic and Nuclear; C075192:gustducin; D010738:Type C Phospholipases; D054799:Phospholipase C beta; C518038:Plcb2 protein, rat; D015293:Transducin