DA reduced GluN2A-containing NMDA-EPSCs in cocaine self-administering rats. A. NMDA-EPSCs in ovBST neurons of control (top) and cocaine self-administering (bottom) rats before drug application (left), after a 10-min bath application of the selective GluN2B antagonist Ro 04-5595 (middle), and after 5 min DA in the presence of Ro (right). B. Effect of Ro, of DA in the presence of Ro, and of the competitive NMDAR antagonist AP-5 on evoked NMDA-EPSCs in ovBST neurons from control and cocaine self-administering rats. *; p < 0.001 from 0 (single sample mean t-tests); (group × drug; F = 27.7, p < 0.0001). Number of neurons/rats indicated above each bar.