INTRAVENOUS MORPHINE SELF-ADMINISTRATION BY RATS WITH LOW VERSUS HIGHSACCHARIN PREFERENCES

An experiment was performed to determine the relationship between sacc harin preference and the self-administration of morphine via the oral and intravenous routes. On the basis of voluntary intake of a sacchari n solution by male rats, low and high preference groups were formed. R ats selected for high saccharin preference self-administered more morp hine intravenously than rats selected for low preference. The two grou ps did not differ in oral morphine intake. The positive relationship b etween the intake of saccharin and intravenous morphine self-administr ation may be due to their mediation by a common mechanism. Measures of taste sensitivity or preference may be useful in identifying individu als at risk for drug abuse.