ODOR-INDUCED INHIBITION OF INTAKE AFTER PAIRING OF ODOR AND CCK-8 IN NEONATAL RATS

This study determined whether an odor that was paired with injections of CCK octapeptide would later come to inhibit independent feeding in neonatal rats. An odor so paired in rats that were not food or materna lly deprived later reduced feeding during the infants' first independe nt feeding experience. Devazepide, the CCKA receptor antagonist, block ed the reduced intake when injected prior to the feeding test. These s tudies demonstrate that CCK is an effective unconditioned stimulus eve n when the animal is not eating during the conditioning process. Furth ermore, the conditioned stimulus (the odor) causes behavioral change e ither by sensitizing a system that includes the CCKA receptor, by caus ing the release of endogenous CCK, or by changing some non-CCK system that enhances the processing of CCKA receptor-mediated information.