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Behavioral Evidence for More than One Taste Signaling Pathway for Sugars in Rats.

Title: Behavioral Evidence for More than One Taste Signaling Pathway for Sugars in Rats.
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Name(s): Schier, Lindsey A, author
Spector, Alan C, author
Type of Resource: text
Genre: Journal Article
Text
Date Issued: 2016-01-06
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: By conventional behavioral measures, rodents respond to natural sugars, such as glucose and fructose, as though they elicit an identical perceptual taste quality. Beyond that, the metabolic and sensory effects of these two sugars are quite different. Considering the capacity to immediately respond to the more metabolically expedient sugar, glucose, would seem advantageous for energy intake, the present experiment assessed whether experience consuming these two sugars would modify taste-guided ingestive responses to their yet unknown distinguishing orosensory properties. One group (GvF) had randomized access to three concentrations of glucose and fructose (0.316, 0.56, 1.1 m) in separate 30-min single access training sessions, whereas control groups received equivalent exposure to the three glucose or fructose concentrations only, or remained sugar naive. Comparison of the microstructural licking patterns for the two sugars revealed that GvF responded more positively to glucose (increased total intake, increased burst size, decreased number of pauses), relative to fructose, across training. As training progressed, GvF rats began to respond more positively to glucose in the first minute of the session when intake is principally taste-driven. During post-training brief-access taste tests, GvF rats licked more for glucose than for fructose, whereas the other training groups did not respond differentially to the two sugars. Additional brief access testing showed that this did not generalize to Na-saccharin or galactose. Thus, in addition to eliciting a common taste signal, glucose and fructose produce distinct signals that are apparently rendered behaviorally relevant and hedonically distinct through experience. The taste pathway(s) underlying this remain to be identified. The T1R2+T1R3 heterodimer is thought by many to be the only taste receptor for sugars. Although most sugars have been conventionally shown to correspondingly produce a unitary taste percept (sweet), there is reason to question this model. Here, we demonstrate that rats that repeatedly consumed two metabolically distinct sugars (glucose and fructose), and thus have had the opportunity to associate the tastes of these sugars with their differential postoral consequences, initially respond identically to the orosensory properties of the two sugars but eventually respond more positively to glucose. Thus, in addition to the previously identified common taste pathway, glucose and fructose must engage distinct orosensory pathways, the underlying molecular and neural mechanisms of which now await discovery.
Identifier: FSU_pmch_26740654 (IID), 10.1523/JNEUROSCI.3356-15.2016 (DOI), PMC4701954 (PMCID), 26740654 (RID), 26740654 (EID), 36/1/113 (PII)
Keywords: T1R2+T1R3, Appetition, Gustatory system, Licking microstructure, Sweeteners, Taste receptors
Grant Number: F32 DC013494, R01 DC009821, R01-DC-009821, F32-DC-013494
Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4701954.
Subject(s): Animals
Dietary Sucrose/metabolism
Food Preferences/physiology
Fructose/metabolism
Glucose/metabolism
Male
Rats
Rats, Sprague-Dawley
Signal Transduction/physiology
Taste/physiology
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_pmch_26740654
Owner Institution: FSU
Is Part Of: The Journal of neuroscience : the official journal of the Society for Neuroscience.
1529-2401
Issue: iss. 1, vol. 36

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Schier, L. A., & Spector, A. C. (2016). Behavioral Evidence for More than One Taste Signaling Pathway for Sugars in Rats. The Journal Of Neuroscience : The Official Journal Of The Society For Neuroscience. Retrieved from http://purl.flvc.org/fsu/fd/FSU_pmch_26740654