title: Flavor preferences conditioned by nutritive and non-nutritive sweeteners in mice.
abstract: Recent studies suggest that preferences are conditioned by nutritive (sucrose) but not by non-nutritive (sucralose) sweeteners in mice. Here we compared the effectiveness of nutritive and non-nutritive sweeteners to condition flavor preferences in three mouse strains. Isopreferred sucrose and sucralose solutions both conditioned flavor preferences in C57BL/6J (B6) mice but sucrose was more effective, consistent with its post-oral appetition action. Subsequent experiments compared flavor conditioning by fructose, which has no post-oral appetition effect in B6 mice, and a sucralose+saccharin mixture (SS) which is highly preferred to fructose in 24-h choice tests. Both sweeteners conditioned flavor preferences but fructose induced stronger preferences than SS. Training B6 mice to drink a flavored SS solution paired with intragastric fructose infusions did not enhance the SS-conditioned preference. Thus, the post-oral nutritive actions of fructose do not explain the sugar's stronger preference conditioning effect. Training B6 mice to drink a flavored fructose solution containing SS did not reduce the sugar-conditioned preference, indicating that SS does not have an off-taste that attenuates conditioning. Although B6 mice strongly preferred flavored SS to flavored fructose in a direct choice test, they preferred the fructose-paired flavor to the SS-paired flavor when these were presented in water. Fructose conditioned a stronger flavor preference than an isopreferred saccharin solution, indicating that sucralose is not responsible for the limited SS conditioning actions. SS is highly preferred by FVB/NJ and CAST/EiJ inbred mice, yet conditioned only weak flavor preferences. It is unclear why highly or equally preferred non-nutritive sweeteners condition weaker preferences than fructose, when all stimulate the same T1r2/T1r3 sweet receptor. Recent findings support the existence of non-T1r2/T1r3 glucose taste sensors; however, there is no evidence for receptors that respond to fructose but not to non-nutritive sweeteners.
authors.affiliation: Brooklyn College and the Graduate School, City University of New York, Brooklyn, New York 11210, USA. Electronic address: AnthonyS@brooklyn.cuny.edu.
authors.forename: Anthony
authors.initials: A
authors.lastname: Sclafani
authors.affiliation: Brooklyn College and the Graduate School, City University of New York, Brooklyn, New York 11210, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Ackroff
mesh_terms: D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects; D005421:Flavoring Agents / Q000494:pharmacology*; D005518:Food Preferences / Q000187:drug effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D064306:Non-Nutritive Sweeteners / Q000494:pharmacology*; D013045:Species Specificity; D013549:Sweetening Agents / Q000494:pharmacology*; D055697:Taste Perception / Q000187:drug effects*
chemical_list: D005421:Flavoring Agents; D064306:Non-Nutritive Sweeteners; D013549:Sweetening Agents
keywords: C57BL/6J mice; CAST/EiJ mice; FVB/NJ mice; Flavor-preference conditioning; Fructose; Saccharin; Sucralose; Sucrose