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This Article Full Text Full Text (PDF) All Versions of this Article: 293/4/R1504    most recent 00364.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Sclafani, A. Articles by Margolskee, R. F. Search for Related Content PubMed PubMed Citation Articles by Sclafani, A. Articles by Margolskee, R. F.

APPETITE, OBESITY, DIGESTION, AND METABOLISM

Fat and carbohydrate preferences in mice: the contribution of -gustducin and Trpm5 taste-signaling proteins

¹Department of Psychology, Brooklyn College of the City University of New York, Brooklyn; ²Department of Biological Sciences, Barnard College, Columbia University, New York; and ³Department of Neuroscience, Mount Sinai School of Medicine, New York, New York

Submitted 22 May 2007 ; accepted in final form 24 July 2007

Trpm5 and -gustducin are key to the transduction of tastes of sugars, amino acids, and bitter compounds. This study investigated the role of these signaling proteins in the preference for fat, starch, and starch-derived polysaccharides (Polycose), using Trpm5 knockout (Trpm5 KO) and -gustducin knockout (Gust KO) mice. In initial two-bottle tests (24 h/day), Trpm5 KO mice showed no preference for soybean oil emulsions (0.313–2.5%), Polycose solutions (0.5–4%), or starch suspensions (0.5–4%). Gust KO mice displayed an attenuated preference for Polycose, but their preferences for soybean oil and starch were comparable to those of C57BL/6J wild-type (WT) mice. Gust KO mice preferred starch to Polycose, whereas WT mice had the opposite preference. After extensive experience with soybean oil emulsions (Intralipid) and Polycose solutions, the Trpm5 KO mice developed preferences comparable to the WT mice, although their absolute intakes remained suppressed. Similarly, Gust KO mice developed a strong Polycose preference with experience, but they continued to consume less than the WT mice. These results implicate -gustducin and Trpm5 as mediators of polysaccharide taste and Trpm5 in fat taste. The disruption in Polycose, but not starch, preference in Gust KO mice indicates that distinct sensory signaling pathways mediate the response to these carbohydrates. The experience-induced rescue of fat and Polycose preferences in the KO mice likely reflects the action of a postoral-conditioning mechanism, which functions in the absence of -gustducin and Trpm5.

soybean oil; Polycose; starch; Sefa Soyate oil; postoral conditioning