Conditioned preference for sweet stimuli in OLETF rat: effects of food deprivation.

Full Abstract

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an outbred strain of Long- Evans Tokushima Otsuka rat (LETO) that lacks CCK-1 receptor expression, is hyperphagic and develops obesity and type-2 diabetes. The present study sought to assess how OLETF rats alter intake, preference, and conditioned preference of palatable solutions after acute food deprivation. Our results show that after 24 h chow restriction, LETO rats increase both sucrose intake and two-bottle sucrose preference relative to their free-fed baseline, whereas OLETF rats do not increase sucrose intake (0.3 M or 1.0 M sucrose) or preference (1.0 M vs. 0.3 M sucrose) when they are food deprived. In contrast, OLETF rats exhibit a higher conditioned flavor preference when sucrose is used as unconditioned stimulus (US) relative to LETO rats, whether overnight food restricted (81% vs. 71% for OLETF and LETO rats, respectively) or free fed (82% vs. 54% for OLETF and LETO rats, respectively) during the test. When a noncaloric saccharin solution is used as US, OLETF rats show a higher preference for the saccharin-associated flavor relative to LETO rats when nondeprived (76% vs. 58% for OLETF and LETO rats, respectively); however, neither strain shows differential conditioned flavor preference for saccharin in the deprivation state during the test. These findings suggest that OLETF rats fail to integrate postabsorptive and orosensory effects of sucrose in a conditioning setting to influence intake. Thus, it appears that OLETF rats form preferences for sucrose based largely on orosensory and hedonic properties of the solution, rather than caloric value.

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Author information

Author/s: De Jonghe, Bart C (BC); Hajnal, Andras (A); Covasa, Mihai (M);

Affiliation: Dept of Nutritional Sciences, College of Health and Human Development, The Pennsylvania State Univ, University Park, PA 16802, USA.

Grants: DK065709 (Agency:NIDDK NIH HHS) ; R01 DK065709-04 (Agency:NIDDK NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural

Journal: American journal of physiology. Regulatory, integrative and comparative physiology (Am J Physiol Regul Integr Comp Physiol), published in United States. (Language: eng)

Reference: 2007-May; vol 292 (issue 5) : pp R1819-27

Dates: Created 2007/05/03; Completed 2007/07/02; Revised 2007/11/14;

PMID: 17272669, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Animals
Conditioning (Psychology) - physiology
Dose-Response Relationship, Drug
Food Deprivation - physiology
Rats

Rats, Inbred OLETF
Saccharin - pharmacology
Sucrose - pharmacology
Sweetening Agents - pharmacology
Taste - drug effects; physiology

Associated Chemicals: Sweetening Agents (0) ; Sucrose (57-50-1) ; Saccharin (81-07-2)

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