Suppression of nocturnal, palatable and glucoprivic intake in rats by the kappa opioid antagonist, nor-binaltorphamine

Abstract

The increased food intake in the rat during the first two hours of the dark cycle was significantly inhibited by central pretreatment with either the selective kappa opioid antagonist, nor-binaltorphamine (NorBNI, 20 micrograms, i.c.v., 53-54%) or naltrexone (NTX, 20 micrograms, i.c.v., 47-60%). Short-term (2 h) intake of a high-fat diet was significantly inhibited by central NorBNI (1-20 micrograms, 33-79%) and NTX (20 micrograms, 47-51%). Hyperphagia induced by the anti-metabolic glucose analogue, 2-deoxy-D-glucose was significantly inhibited by central NorBNI (20 micrograms, 40-68%) and NTX (20 micrograms, 28-69%). These data suggest that the kappa receptor subtype, in addition to other opioid receptor subtypes, influence these forms of feeding behavior.