The expression of bitter taste receptors in mesenteric, cerebral and omental arteries.

AIM: Bitter taste is sensed by the bitter taste receptor (TAS2R), which is mainly expressed in the tongue as well as in extra-oral organs, such as the gastrointestinal tract, respiratory tract, brain, heart and testis. This study aimed to investigate whether TAS2R is expressed in the mesenteric, cerebral and omental arteries.

MAIN METHODS: The expression levels of TAS2R mRNA and protein were determined by reverse-transcription polymerase chain reaction and Western blotting, respectively. The location of TAS2R was determined by immunofluorescence imaging. TAS2R agonists were used in a sensitive myograph to study the function of TAS2R in arteries.

KEY FINDINGS: The mRNA of rat TAS2Rs, including rTAS2R39, rTAS2R40, rTAS2R108, rTAS2R114, rTAS2R130, rTAS2R137, and rTAS2R140, was expressed in rat mesenteric and cerebral arteries, but rTAS2R114 was not expressed in the cerebral arteries. The mRNA of human TAS2Rs, including hTAS2R3, hTAS2R4, hTAS2R7, hTAS2R10, hTAS2R14, hTAS2R39 and hTAS2R40, was expressed in human omental arteries. The TAS2R7 protein was expressed in rat mesenteric and cerebral arteries, as well as in human omental arteries. Immunofluorescence imaging confirmed that TAS2R7 was located in vascular smooth muscle cells and endothelial cells. The TAS2R agonists, chloroquine and quinine relaxed rat mesenteric arteries and cerebral arteries and human omental arteries in a concentration-dependent manner.

SIGNIFICANCE: TAS2R is expressed in the arteries of systemic circulation, including rat mesenteric and cerebral arteries and human omental arteries. This study provides evidence that TAS2R do exist in the arteries and may be involved in the mediation of vessel functions.