Oromotor and somatic taste reactivity during sucrose meals reveals internal state and stimulus palatability after gastric bypass in rats

Ginger D. Blonde, Clare Marie Mathes, Tadashi Inui, Elizabeth A. Hamel, Ruth K. Price, M. Barbara E. Livingstone, Carel W le Roux, Alan Craig Spector

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After Roux-en-Y gastric bypass (RYGB), rats consume less high-energy foods and fluids, though whether this reflects a concomitant change in palatability remains unclear. By measuring behavior during intraorally delivered liquid meals across days (1 water, 8 sucrose sessions), we showed that RYGB rats (RYGB, n = 8/sex) consumed less 1.0 M sucrose than their sham surgery counterparts (SHAM, n = 8 males, n = 11 females) but displayed similarly high levels of ingestive taste reactivity responses at the start of infusions. Relative to water, both groups increased intake of sucrose, and ingestive responses were dominated by tongue protrusions rather than mouth movements. Thus, RYGB animals still found sucrose palatable despite consuming less than the SHAM group. As the intraoral infusion progressed but before meal termination, aversive behavior remained low and both RYGB and SHAM animals showed fewer ingestive responses, predominantly mouth movements as opposed to tongue protrusions. This shift in responsiveness unrelated to surgical manipulation suggests negative alliesthesia, or a decreased palatability, as rats approach satiation. Notably, only in RYGB rats, across sessions, there was a striking emergence of aversive behavior immediately after the sucrose meal. Thus, although lower intake in RYGB rats seems independent of the hedonic taste properties of sucrose, taste reactivity behavior in these animals immediately after termination of a liquid meal appears to be influenced by postoral events and reflects a state of nimiety or excessive consumption. Measurement of taste reactivity behaviors during an intraorally delivered meal represents a promising way to make inferences about internal state in nonverbal preclinical models.
Original languageEnglish
Pages (from-to)R204-R218
Number of pages44
JournalAJP - Regulatory, Integrative and Comparative Physiology
Issue number3
Early online date19 Jan 2022
Publication statusPublished (in print/issue) - 1 Mar 2022

Bibliographical note

Funding Information:
Research reported in this publication was supported in part by a summer grant and Gund funds from Baldwin Wallace University, and by the US-Ireland Research and Development Partnership program through the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (R01DK106112), the Health and Social Care R&D Division of Northern Ireland (STL/5062/14) and the Medical Research Council (MC_PC_16017), and the Health Research Board of the Republic of Ireland (USIRL-2006).

Funding Information:
Carel W. le Roux reports grants from Irish Research Council, Science Foundation Ireland, Anabio, and the Health Research Board. He serves on advisory boards of NovoNordisk, Herbalife, GI Dynamics, Eli Lilly, Johnson and Johnson, Sanofi Aventis, Astra Zeneca, Janssen, Bristol-Myers Squibb, Keyron, and Boehringer-Ingelheim, outside the area of work commented on here. None of the other authors has any conflicts of interest, financial or otherwise, to disclose.

Publisher Copyright:
Copyright © 2022 the American Physiological Society.


  • alliesthesia
  • bariatric surgery
  • nimiety
  • taste reactivity
  • Physiology
  • Physiology (medical)


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