Role of k-opioid receptor agonist U-50,488H in consummatory successive negative contrast

Abstract

The role of K agonist U-50,488H in cSNC was explored in four experiments. Experiment one revealed that U-50 failed to influence cSNC on trial 11 but showed both an attenuation with low dose of U-50 and exaggeration of cSNC in medium and high dose of U-50 by impairing recovery. Experiment two confirmed a selective attenuation for trial 12 of cSNC in groups given low dose, while the medium dose impaired recovery. Experiment three explored the possibility that the effects of U-50 on cSNC may be the result of an influence on alternative mechanisms such as locomotor activity. Results revealed that U-50 showed no influence from saline control. Experiment four explored the effects of U-50 on posttrial 11 and revealed that U-50 significantly enhanced contrast, on trial 12, indicating an effect on associative mechanisms involved in the memory of the downshift experience.