Figure 5.
Adenosine receptor Adora2b is associated with Tas1r2, a sweet taste receptor subunit in taste cells. A, RT-PCR on isolated vallate taste buds (tb) and non-taste lingual epithelium (nt) reveals prominent expression of Adora2b and lower levels of Adora1 in taste buds. Neither Adora2a nor Adora3 were detected. Positive and negative controls run in parallel included brain (br) and H2O in place of template (–). RT-PCR for Snap25 served as a positive control for taste buds. B, Single-cell RT-PCR on 23 individual GFP-positive cells (i.e., Type II Receptor cells) from taste buds of Plcb2-GFP mice. Aliquots (20%) of each cell's cDNA were tested for Adora2b, one sweet receptor subunit (Tas1r2) and two bitter receptors (Tas2r105, Tas2r108). One cell (RT−) was processed without reverse transcriptase, and yielded no PCR products.