MORPHINE ENHANCES SELECTION OF BOTH SUCROSE AND ETHANOL IN A 2-BOTTLETEST

The influence of a low dose of morphine on the self-selection of alcoh ol and sucrose solutions is investigated. When given a choice between sucrose sweetened ethanol and plain water, rats show a significant pre ference for the sweetened ethanol. However, when given a choice betwee n sweetened ethanol and sweetened water, rats increase consumption of sweetened water. These results suggest that the low-dose morphine enha ncement of sweetened alcohol solutions is mediated by the reinforcing properties of sucrose not ethanol. However, when rats receive small do ses of morphine and a choice between unsweetened ethanol and water, th e rats increase consumption of ethanol. Therefore, a low dose of morph ine enhances the self-selection of both sucrose and ethanol solutions. This provides additional confirmation that opioids may enhance the re warding properties of a variety of appetite reinforcers. Copyright (C) 1997 Elsevier Science Inc.