Screening for G‐protein‐coupled receptors expressed in mouse taste papillae

ABSTRACT To further explore the repertoire of receptors important for the physiology of the peripheral taste system, we conducted a screening for genes encoding G‐protein‐coupled receptors (GPCRs) expressed in lingual papillae. A total of 13 genes coding for GPCRs belonging to four broad categories were selected as targets to explore their mRNA expression profile by RT–PCR on a panel of mouse tissues. The selected targets comprised seven orphan GPCRs, four fatty acid receptors and two proton‐sensing GPCRs. Several genes were found expressed in taste papillae, with GPR68, GPR120 and GPCR5D displaying somewhat restricted expression patterns. The gene coding for GPR120, a receptor activated by long chain fatty acids, was abundant in circumvallate, foliate and fungiform papillae, making it a particularly interesting candidate. In situ hybridization experiments revealed that GPR120 mRNA is confined to taste buds. Immunohistochemistry on circumvallate papillae sections indicated that GPR120 is present in taste receptor cells as well as in a subset of presynaptic cells. Our results expand the list of GPCRs potentially involved in peripheral gustatory function. Copyright © 2011 John Wiley & Sons, Ltd.