Figure 1.

Schema of general procedures and experimental design. A, Immunoblotting studies. After self-administration (SA) (10 daily sessions of 1 or 6 h access to saline or 6 h access to cocaine), animals were divided to two conditions: 3 or 30 d of withdrawal. After withdrawal, animals were either subjected to a 2 h cue test, immediately killed, and the brains harvested for immunoblotting analysis, or were simply killed (with no other experimental manipulation) with brains harvested for immunoblotting. B, Neuropharmacological studies. The procedure was the same as that illustrated in A with one exception: treatment after withdrawal. Here, cohorts of subjects received one or two 30 min cue tests, and brains were harvested for histological verification of microinjector placements.