Systematic Screening of Gene Expression Using a cDNA Macroarray

In the field of drug abuse research, a critical need is to identify the events that underlie the transition from recreational drug use to drug abuse and addiction. It is clear that the mechanisms will involve psychosocial, behavioral, neuroanatomical, and molecular biological components. This last facet, the molecular component, is the subject of the present discussion and the motivation for the use of DNA arrays. Although the contributions of social and behavioral components to the etiology of drug abuse are substantial, growing evidence shows that long-term drug administration produces persistent changes in brain gene expression. The current thinking is that these changes in gene expression may contribute to an allostatic state that is manifested in physiological and behavioral phenomena such as physical dependence, tolerance, withdrawal, craving, sensitization, and psychological addiction (1 –4 ).