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. Author manuscript; available in PMC: 2013 Oct 1.
Published in final edited form as: Alcohol Clin Exp Res. 2012 Mar 20;36(10):1710–1719. doi: 10.1111/j.1530-0277.2012.01762.x

Figure 3.

Figure 3

Prototypical rate histograms (20 s mean frequency bins) of posterior VTA putative dopamine neurons in separate nondependent alcohol drinking P rats for (a) cumulative NMDA current-responses, and (b) concurrent NMDA and AP5 ejections. (a) NMDA produced current-dependent increases in firing frequency. Occurrence of depolarization block was exemplified by a rapid decrease in firing frequency immediately following the peak response during the −10 nA ejection period. Horizontal bars indicate NMDA ejection periods accompanied by ejection currents (−2, −4, −6, −8, −10 nA). (b) NMDA (−6 nA) increased firing frequency which stabilized during the 3rd and 4th ejections. Concomitant ejection of AP5 (a competitive NMDA receptor antagonist) at −5 nA blocked the NMDA-induced increases in firing frequency. When the AP5 current was terminated, NMDA ejection (−6 nA) again increased firing frequency which stabilized during the 2nd and 3rd ejections. Horizontal bars indicate NMDA (black bars) and AP5 (gray bar) ejection periods and currents.