Expression and localization of taste receptor genes in the vallate papillae of rats: effect of zinc deficiency.
CONCLUSIONS
We found a difference in expression sites between TAS2Rs and ENaC (epithelial sodium channels). The number of TAS2R-positive cells and ENaC-positive cells were decreased in zinc-deficient diet rats. These findings suggest that decreased expression of taste receptor genes may play an important role in the onset of zinc deficiency-associated taste disorder.


OBJECTIVE
The present study was aimed at histologically investigating the expression and localization of TAS2Rs and ENaC in the vallate taste buds of rats. Changes in expression of the taste receptor genes in zinc-deficient rats were also investigated.


METHODS
The vallate papillae of five rats fed a normal diet and five rats fed a zinc-deficient diet were used. In situ hybridization was performed to investigate the expression and localization of TAS2Rs and ENaC. TAS2R-positive cells per taste bud were counted, and differences in number between the normal and zinc-deficient diet rats were investigated.


RESULTS
In the normal rats, expression of TAS2Rs was observed specifically in the taste bud cells. In contrast, ENaC-positive cells were observed in a part of the taste bud cells and a large number of epithelial cells. Fewer cells were positive for TAS2Rs and ENaC in the zinc-deficient diet rats.
Department of Otolaryngology-Head and Neck Surgery, Tokyo, Japan. meat09023@g.nihon-u.ac.jp
Atsuo
A
Ikeda
Hiroki
H
Sekine
Kyoichi
K
Takao
Minoru
M
Ikeda
D000818:Animals; D004032:Diet; D053503:Epithelial Sodium Channels / Q000235:genetics / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D013650:Taste Buds / Q000378:metabolism*; D013651:Taste Disorders / Q000378:metabolism*; D015032:Zinc / Q000172:deficiency*
D053503:Epithelial Sodium Channels; D043562:Receptors, G-Protein-Coupled; D015032:Zinc