Sensory transduction for many taste stimuli such as sugars, some bitter compounds and amino acids is thought to be mediated via G protein-coupled receptors (GPCRs), although no such receptors that respond to taste stimuli are yet identified. Monosodium L-glutamate (l-MSG), a natural component of many foods, is an important gustatory stimulus believed to signal dietary protein. We describe a GPCR cloned from rat taste buds and functionally expressed in CHO cells. The receptor couples negatively to a cAMP cascade and shows an unusual concentration–response relationship. The similarity of its properties to MSG taste suggests that this receptor is a taste receptor for glutamate.
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This work was supported by grants from NIH/NIDCD (DC 03013) and from Cultor Food Science, Inc. We are also grateful for support from the Umami Manufacturers' Association of Japan during the early stages of this study. We acknowledge technical assistance from Cynthia Lamp and Helena de Carvalho.
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Chaudhari, N., Landin, A. & Roper, S. A metabotropic glutamate receptor variant functions as a taste receptor . Nat Neurosci 3, 113–119 (2000). https://doi.org/10.1038/72053
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