Roux-en-Y gastric bypass in rats increases sucrose taste-related motivated behavior independent of pharmacological GLP-1-receptor modulation

Am J Physiol Regul Integr Comp Physiol. 2012 Mar 15;302(6):R751-67. doi: 10.1152/ajpregu.00214.2011. Epub 2011 Dec 14.

Abstract

Roux-en-Y gastric bypass (RYGB) surgery has been shown to decrease consummatory responsiveness of rats to high sucrose concentrations, and genetic deletion of glucagon-like peptide-1 receptors (GLP-1R) has been shown to decrease consummatory responsiveness of mice to low-sucrose concentrations. Here we assessed the effects of RYGB and pharmacological GLP-1R modulation on sucrose licking by chow-fed rats in a brief-access test that assessed consummatory and appetitive behaviors. Rats were tested while fasted presurgically and postsurgically and while nondeprived postsurgically and 5 h after intraperitoneal injections with the GLP-1R antagonist exendin-3(9-39) (30 μg/kg), agonist exendin-4 (1 μg/kg), and vehicle in 30-min sessions during which a sucrose concentration series (0.01-1.0 M) was presented in 10-s trials. Other rats were tested postsurgically or 15 min after peptide or vehicle injection while fasted and while nondeprived. Independent of food-deprivation state, sucrose experience, or GLP-1R modulation, RYGB rats took 1.5-3× as many trials as sham-operated rats, indicating increased appetitive behavior. Under nondeprived conditions, RYGB rats with presurgical sucrose experience licked more to sucrose relative to water compared with sham-operated rats. Exendin-4 and exendin-3(9-39) impacted 0.3 M sucrose intake in a one-bottle test, but never interacted with surgical group to affect brief-access responding. Unlike prior reports in both clearly obese and relatively leaner rats given RYGB and in GLP-1R knockout mice, we found that neither RYGB nor GLP-1R blockade decreased consummatory responsiveness to sucrose in our less obese chow-fed rats. Collectively, these results highlight the fact that changes in taste-driven motivated behavior to sucrose after RYGB and/or GLP-1R modulation are very model and measure dependent.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Appetite / drug effects
  • Appetite / physiology
  • Behavior, Animal / drug effects*
  • Behavior, Animal / physiology
  • Dose-Response Relationship, Drug
  • Drinking / physiology
  • Eating / drug effects
  • Eating / physiology
  • Exenatide
  • Gastric Bypass*
  • Glucagon-Like Peptide-1 Receptor
  • Injections, Intraperitoneal
  • Male
  • Models, Animal
  • Peptide Fragments / administration & dosage
  • Peptide Fragments / pharmacology*
  • Peptides / administration & dosage
  • Peptides / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Glucagon / agonists
  • Receptors, Glucagon / antagonists & inhibitors
  • Receptors, Glucagon / drug effects*
  • Sucrose / pharmacology*
  • Time Factors
  • Venoms / administration & dosage
  • Venoms / pharmacology*

Substances

  • Glp1r protein, mouse
  • Glp1r protein, rat
  • Glucagon-Like Peptide-1 Receptor
  • Peptide Fragments
  • Peptides
  • Receptors, Glucagon
  • Venoms
  • exendin (9-39)
  • Sucrose
  • Exenatide