Glucagon signaling modulates sweet taste responsiveness.
The gustatory system provides critical information about the quality and nutritional value of food before it is ingested. Thus, physiological mechanisms that modulate taste function in the context of nutritional needs or metabolic status could optimize ingestive decisions. We report that glucagon, which plays important roles in the maintenance of glucose homeostasis, enhances sweet taste responsiveness through local actions in the mouse gustatory epithelium. Using immunohistochemistry and confocal microscopy, we found that glucagon and its receptor (GlucR) are coexpressed in a subset of mouse taste receptor cells. Most of these cells also express the T1R3 taste receptor implicated in sweet and/or umami taste. Genetic or pharmacological disruption of glucagon signaling in behaving mice indicated a critical role for glucagon in the modulation of taste responsiveness. Scg5(-/-) mice, which lack mature glucagon, had significantly reduced responsiveness to sucrose as compared to wild-type littermates in brief-access taste tests. No significant differences were seen in responses to prototypical salty, sour, or bitter stimuli. Taste responsiveness to sucrose was similarly reduced upon acute and local disruption of glucagon signaling by the GlucR antagonist L-168,049. Together, these data indicate a role for local glucagon signaling in the peripheral modulation of sweet taste responsiveness.
Elson
Amanda E T
AE
Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 S. Penn St., Rm. S251, Baltimore, MD 21201, USA.
Dotson
Cedrick D
CD
Egan
Josephine M
JM
Munger
Steven D
SD
D000818:Animals; D001483:Base Sequence; D001522:Behavior, Animal; D017931:DNA Primers; D005934:Glucagon / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018027:Receptors, Glucagon / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013649:Taste; D013650:Taste Buds / Q000166:cytology / Q000502:physiology
D017931:DNA Primers; D018027:Receptors, Glucagon; D005934:Glucagon