Figure 3.

Ventral tegmental area infusions of the MEK inhibitor U0126 attenuate BDNF-induced potentiation of cocaine seeking induced by re-exposure to cocaine cues after 3 and 10 d of withdrawal. A, Mean (±SEM) responses per 2 hr on the previously active lever during the tests for cocaine seeking conducted after 3 and 10 d of withdrawal from cocaine. During the test sessions, cocaine was not available, and lever presses resulted in the delivery of the tone-light cue previously paired with drug infusions. Infusions of U0126 or its vehicle (10% DMSO) were given 20 min before the infusions of BDNF or its vehicle, which were given 1-2 hr after the last training session. B, Timeline of the experiment. ^*Significantly different from the other groups, p < 0.05 (n = 9-11 per group). SA, Self-administration.