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Am J Physiol Regul Integr Comp Physiol. 2016 Oct 1;311(4):R742-R755. doi: 10.1152/ajpregu.00155.2016. Epub 2016 Aug 10.

Post-oral sugar detection rapidly and chemospecifically modulates taste-guided behavior.

Author information

1
Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida schier@psy.fsu.edu.
2
Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida.

Abstract

Several recent studies have shown that post-oral sugar sensing rapidly stimulates ingestion. Here, we explored the specificity with which early-phase post-oral sugar sensing influenced ingestive motivation. In experiment 1, rats were trained to associate the consumption of 0.3 M sucrose with injections of LiCl (3.0 meq/kg ip, conditioned taste aversion) or given equivalent exposures to the stimuli, but in an unpaired fashion. Then, all rats were subjected to two brief-access tests to assess appetitive and consummatory responses to the taste properties of sucrose (0.01-1.0 M), 0.12 M NaCl, and dH2O (in 10-s trials in randomized blocks). Intraduodenal infusions of either 0.3 M sucrose or equiosmolar 0.15 M NaCl (3.0 ml) were administered, beginning just before each test. For unpaired rats, intraduodenal sucrose specifically enhanced licking for 0.03-1.0 M sucrose, with no effect on trial initiation, relative to intraduodenal NaCl. Rats with an aversion to sucrose suppressed licking responses to sucrose in a concentration-dependent manner, as expected, but the intraduodenal sucrose preload did not appear to further influence licking responses; instead, intraduodenal sucrose attenuated trial initiation. Using a serial taste reactivity (TR) paradigm, however, experiment 2 demonstrated that intraduodenal sucrose preloads suppressed ingestive oromotor responses to intraorally delivered sucrose in rats with a sucrose aversion. Finally, experiment 3 showed that intraduodenal sucrose preloads enhanced preferential licking to some representative tastants tested (sucrose, Polycose, and Intralipid), but not others (NaCl, quinine). Together, the results suggest that the early phase-reinforcing efficacy of post-oral sugar is dependent on the sensory and motivational properties of the ingesta.

KEYWORDS:

chemosensory; gastrointestinal; gustatory system; nutrient sensing; visceral

PMID:
27511277
PMCID:
PMC5142159
DOI:
10.1152/ajpregu.00155.2016
[Indexed for MEDLINE]
Free PMC Article

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