The role of setting in the oral self-administration of alcohol in the rat.

Rationale: We have previously found that rats that were kept at all times in the self-administration (SA) chambers (resident group) self-administered more heroin than rats that were transferred to the SA chambers immediately before testing (Non-Resident group). Alcohol resembles heroin in its ability to produce, at recreational doses, mood elevation, euphoria, drowsiness, and sedation. Furthermore, alcohol presents some similarities with the mechanisms of action of heroin at the levels of the mesostriatal circuitry.

Environmental modulation of cocaine self-administration in the rat.

Rationale: Previous studies have shown that environmental context can powerfully modulate the induction of psychomotor sensitization to cocaine in the rat. Rats that receive repeated administrations of cocaine in association with environmental novelty exhibit greater psychomotor sensitization than animals that receive the same treatments in their home cages.

Objectives: The goal of the present study was to investigate whether environmental context can exert its modulatory influence also on cocaine self-administration.