RT Journal Article SR Electronic T1 Regulation of Ingestive Behaviors in the Rat by GSK1521498, a Novel μ-Opioid Receptor-Selective Inverse Agonist JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 24 OP 34 DO 10.1124/jpet.111.180943 VO 339 IS 1 A1 Diane M. Ignar A1 Aaron S. Goetz A1 Kimberly Nichols Noble A1 Luz Helena Carballo A1 Andrea E. Stroup A1 Julie C. Fisher A1 Joyce A. Boucheron A1 Tracy A. Brainard A1 Andrew L. Larkin A1 Andrea H. Epperly A1 Todd W. Shearer A1 Scott D. Sorensen A1 Jason D. Speake A1 Jonathan D. Hommel YR 2011 UL http://jpet.aspetjournals.org/content/339/1/24.abstract AB μ-Opioid receptor (MOR) agonism induces palatable food consumption principally through modulation of the rewarding properties of food. N-{[3,5-difluoro-3′-(1H-1,2,4-triazol-3-yl)-4-biphenylyl]methyl}-2,3-dihydro-1H-inden-2-amine (GSK1521498) is a novel opioid receptor inverse agonist that, on the basis of in vitro affinity assays, is greater than 10- or 50-fold selective for human or rat MOR, respectively, compared with κ-opioid receptors (KOR) and δ-opioid receptors (DOR). Likewise, preferential MOR occupancy versus KOR and DOR was observed by autoradiography in brain slices from Long Evans rats dosed orally with the drug. GSK1521498 suppressed nocturnal food consumption of standard or palatable chow in lean and diet-induced obese (DIO) Long Evans rats. Both the dose-response relationship and time course of efficacy in lean rats fed palatable chow correlated with μ receptor occupancy and the plasma concentration profile of the drug. Chronic oral administration of GSK1521498 induced body weight loss in DIO rats, which comprised fat mass reduction. The reduction in body weight was equivalent to the cumulative reduction in food consumption; thus, the effect of GSK1521498 on body weight is related to inhibition of food consumption. GSK1521498 suppressed the preference for sucrose-containing solutions in lean rats. In operant response models also using lean rats, GSK1521498 reduced the reinforcement efficacy of palatable food reward and enhanced satiety. In conclusion, GSK1521498 is a potent, MOR-selective inverse agonist that modulates the hedonic aspects of ingestion and, therefore, could represent a pharmacological treatment for obesity and binge-eating disorders.