Taste responsiveness to sweeteners is resistant to elevations in plasma leptin.
There is uncertainty about the relationship between plasma leptin and sweet taste in mice. Whereas 2 studies have reported that elevations in plasma leptin diminish responsiveness to sweeteners, another found that they enhanced responsiveness to sucrose. We evaluated the impact of plasma leptin on sweet taste in C57BL/6J (B6) and leptin-deficient ob/ob mice. Although mice expressed the long-form leptin receptor (LepRb) selectively in Type 2 taste cells, leptin failed to activate a critical leptin-signaling protein, STAT3, in taste cells. Similarly, we did not observe any impact of intraperitoneal (i.p.) leptin treatment on chorda tympani nerve responses to sweeteners in B6 or ob/ob mice. Finally, there was no effect of leptin treatment on initial licking responses to several sucrose concentrations in B6 mice. We confirmed that basal plasma leptin levels did not exceed 10ng/mL, regardless of time of day, physiological state, or body weight, suggesting that taste cell LepRb were not desensitized to leptin in our studies. Furthermore, i.p. leptin injections produced plasma leptin levels that exceeded those previously reported to exert taste effects. We conclude that any effect of plasma leptin on taste responsiveness to sweeteners is subtle and manifests itself only under specific experimental conditions.
Department of Biology, Barnard College, Columbia University, 3009 Broadway New York, NY 10027, USA, jglendin@barnard.edu.
John I
JI
Glendinning
Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 S. Penn St., Baltimore, MD 21201, USA.
Amanda E T
AE
Elson
Department of Biology, Barnard College, Columbia University, 3009 Broadway New York, NY 10027, USA.
Salina
S
Kalik
Department of Biology, Barnard College, Columbia University, 3009 Broadway New York, NY 10027, USA.
Yvett
Y
Sosa
Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan, Ann Arbor, MI 48109, USA and.
Christa M
CM
Patterson
Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan, Ann Arbor, MI 48109, USA and.
Martin G
MG
Myers
Department of Anatomy & Neurobiology, University of Maryland School of Medicine, 20 S. Penn St., Baltimore, MD 21201, USA, Department of Medicine, Division of Endocrinology, Diabetes, and Nutrition, University of Maryland School of Medicine, HH-495, Baltimore, MD 21201, USA.
Steven D
SD
Munger
D000818:Animals; D007274:Injections, Intraperitoneal; D020738:Leptin / Q000008:administration & dosage / Q000097:blood* / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D054411:Receptors, Leptin / Q000378:metabolism; D013549:Sweetening Agents / Q000494:pharmacology*; D013649:Taste / Q000187:drug effects* / Q000502:physiology*; D014059:Tongue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D020738:Leptin; D054411:Receptors, Leptin; D013549:Sweetening Agents
chorda tympani nerve; leptin; mice; modulation; sweet taste