Figure 2.

Optogenetically Manipulating DA Release in the Rat NAc during Ethanol-Seeking Behavior and under Anesthetized Conditions

(A) Schematic configuration for optical activation of accumbal DA terminals that was used to trigger tonic and phasic patterns of DA transmission.

(B) Tonic DA release patterns were triggered by blue light applied for 1 min at 5 Hz with 1-s intervals between stimulations (10 min total). A three-dimensional color plot topographically represents electrochemical changes detected with voltammetry in the rat NAc over 70 s.

(C) Phasic DA release patterns were induced by blue light stimulation (1 s, 50 Hz) with 15-s intervals between each pulse train for the first 10 min of the operant session. A color plot depicts the increase in DA release (uninterrupted green rise) that is time locked to optical activation. Four divided green spikes denote DA transients, which are time-locked to optical stimulations. Therefore, two main patterns of DA transmission, phasic and tonic, could be optogenetically mimicked during the operant behavior test. See also Figures S3–S5.

(D and E) Changes in alcohol-seeking behavior of rats (n = 7) were evaluated by measures of the latency to the first lever press and total number of lever presses during non-reinforced sessions. (D) No significant changes in the latency to the first press were found between sessions with (tonic and phasic) and without stimulations (p > 0.05). (E) Shifting DA release in the NAc into a tonic mode resulted in a significant decrease in the number of lever presses. However, phasic activation of the NAc significantly increased this measure.

*p < 0.05; ***p < 0.001 (Mann-Whitney). Data are mean ± SEM.