ABSTRACT
The.upper.gastrointestinal. tract. is.a.critical. site. for. the.negative. feedback.control. of. food. intake.. Its. significance. is. supported. by. studies. in. human. and. nonhuman. primates,.as.well.as.in.rodents,.demonstrating.that,.when.nutrients.fail.to.stimulate. the.proximal.duodenum.during.sham.feeding,.both.meal.duration.and.the.amount. of.food.consumed.are.dramatically. increased..Furthermore,. infusions.of.nutrients. directly.into.the.duodenum.at.rates.that.mimic.the.physiological.time.course.of.gastric.emptying.have.been.shown.to.potently.and.dose-dependently.reduce.subsequent. food.intake..Gastrointestinal.nutrients.also.potently.slow.gastric.emptying,.depending.on.their.caloric.density,.providing.a.local.means.by.which.nutrient.absorption. and.nutrient-stimulated.gut.hormone.release.are.regulated.to.modulate.energy.availability.and. thereby.help.determine.energy.balance..During.a. typical.meal,.which. is.the.functional.unit.of.ingestion.in.humans,.nonhuman.primates,.and.rodents,.the. majority.of. ingested. food.accumulates.within. the.stomach,.pending. its.controlled. gastric.emptying.into.small.intestinal.sites.that.mediate.nutrient.absorption..Nutrient. absorption. begins. within. minutes. of. the. onset. of. a. meal,. and,. depending. on. the.
13.1. Introduction................................................................................................. 253 13.2. Gut-Brain.Neuraxis.....................................................................................254 13.3. Gut.Signaling.in.the.Absorptive.Phase.—.Candidate.Mediators................ 255 13.4. Chemical.Sensing.in.the.Gut....................................................................... 259 13.5. Electrical.Gut.Stimulation........................................................................... 259 13.6. Forebrain.Neural.Representation.of.a.Meal................................................260 13.7. A.Translational.Approach.to.Gut-Brain.Communication.in.the.Control.
