Fig. 4. Blocking adenosine A2A receptors during extinction has no effects on extinction responding.
(a) Average number of cocaine infusions and active lever responses in each 4 h session over the last 6 days of the self-administration phase. (b) A2AR antagonism by SCH 442416 (0.3 mg/kg, 1 mg/kg, or 3 mg/kg, i.p.), has no effect on extinction responding when administered immediately prior to the beginning of each 4 h extinction session.