Research [15] suggests that opiates and palatable foods influence the same neural pathways. In light of this potentially common substrate, research on the actions of dietary manipulations on the behavioral consequences of opiate drugs could provide strategies for maintaining drug abstinence and preventing relapse. An important issue that needs to be resolved is whether the alterations in opiate-related behaviors, found in conjunction with sweet consumption (e.g. enhanced pain-relief [41]) is a function of taste hedonics or alterations in metabolic responses of these sweet substances. Bypassing the gustatory response, by administering the sugar into the peritoneum or directly into brain sites could help to resolve this issue. The proposed research will investigate the behavioral consequences of interactions between various opiate agonists and ip and central administration of d-glucose. Research will focus on alterations to opiate-induced antinocieption by d-glucose, as well as alternate sugars such as fructose and 1-glucose (a stereoisomer of d-glucose) when injected ip or centrally in the lateral ventricles and periaqueductal gray. The hot-water tail-withdrawal procedure will be used to assess antinociception. Additionally, conditioned place preference and precipitated withdrawal will be used to assess reward and withdrawal related behaviors.