Evaluating the gastrointestinal taste hypothesis with a novel behavioral paradigm: Rats exhibit stimulus-bound suppression of ongoing ingestion to intraduodenal bitter or sweet stimuli associated with malaise
Abstract
The present set of experiments developed a novel behavioral paradigm to examine whether taste-like sensory signals are detected in the intestine and functionally integrated with ongoing ingestive behavior. Using a modified conditioned taste aversion procedure, these experiments show that rats detect and track with high temporal resolution the presence of a bitter cue in the intestine to temporarily suspend intake. This response to bitter is partially mediated by the gut peptide cholecystokinin acting in a paracrine fashion. The results also show that rats encode information about sweet cues in the intestine to proactively control intake in anticipation of malaise, but only under conditions in which the sweet taste is received in combination with a functional carbohydrate in training. Consistent with this, intestinal sweet taste reception alone does not contribute to the unconditioned negative feedback of two carbohydrates. These results provide evidence that post-oral preabsorptive chemoreception is more dynamic than previously thought and the chemical qualities of foods, beyond their macronutrient content, are encoded. The intestinal taste aversion paradigm developed here provides a sensitive and effective protocol for evaluating which tastants—and concentrations of tastants—in the lumen of the gut can control ingestion.
Degree
Ph.D.
Advisors
Powley, Purdue University.
Subject Area
Neurosciences|Behavioral psychology
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