Rats display marked variability in their willingness to consume the artificial sweetener sucralose. Most rats are classified as sucralose avoiders (~75%; SA) while the remaining subset
can be classified as sucralose preferrers (~25%; SP). Here, I have shown that these phenotypic differences in the consumption of sucralose are the result of highly consistent and robust
behaviors and potentially represent a meaningful, physiological difference in sensory processing with functional consequences for diet choice and weight gain. Specifically, the emergence of a
sucralose preference profile is stable across both sexes and at least two rat strains. Furthermore, utilizing an adaptation of the two-response taste discrimination psychophysical paradigm, I
have demonstrated that the differences in the consumption of sucralose are sensory based. The taste quality of sucralose appears to be sufficient to split rats into their respective
phenotypic groups. These sensory differences appear to generalize to other artificial sweeteners and stimuli with a putative, binary sweet-like and bitter-like taste profile as SA and SP
differ in their intakes of concentrated saccharin solutions and quinine-adulterated sucrose in a manner consistent with their responses to sucralose. These sensory differences appear to be
mediated by a disparity in the processing of 'sweet' tastes. Immunohistochemical analysis of patterns of neuronal activation demonstrate that SA may perceive a more salient 'bitter' percept
from sucralose, most likely due to a reduced sensitivity to the 'sweet'-like qualities of sucralose. Conversely, SP perceive identical concentrations of sucralose as a mixture of 'sweet' and
'bitter' with the most salient quality being that of a sucrose-like 'sweet' taste; a sensory profile consistent with a number of other artificial sweeteners. These differences in sensory
processing may be the result of a genetic mutation in one of the Tas1R genes that encode the two proteins that form the functional 'sweet-taste' receptor. Evidence for such a conclusion is
provided by the observed differential intake of sucralose and at least one other artificial sweetener, as well as differences in the avidity for sucrose solutions as assessed through
brief-access licking tests. The demonstrated variation in sensory processing may play a central role in SP, relative to SA, failing to regulate caloric intake, and their subsequent increased
propensity for weight gain, when given access to a highly palatable diet. As the increased availability to highly palatable, energy-dense foods has been identified as a contributing factor to
the current obesity epidemic, these data may provide a direct, testable model for examining the influence of a 'sweet-tooth' on diet choice and excessive weight gain. / A Dissertation submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2014. / September 12, 2014. / Bimodal, Ingestive Behavior, Psychophysics, Sucralose, Sweeteners, Taste / Includes bibliographical references. / Lisa Eckel, Professor Directing Dissertation; Joyce Carbonell, Committee Member; Thomas Houpt, Committee Member; Alan Spector, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_252860 |
| Contributors | Loney, Gregory C. (authoraut), Eckel, Lisa A. (professor directing dissertation), Bales, William D. (university representative), Carbonell, Joyce L., 1951- (committee member), Houpt, Thomas A. (committee member), Spector, Alan C. (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Psychology (degree granting department) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (125 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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