Figure 3. Histograms of light-evoked RGC responses to olfactory stimulation in zebrafish that were treated with SCH 23390 (a dopamine D1 receptor antagonist, A) or sulpiride (a dopamine D2 receptor antagonist, B).

When the D1 receptors were blocked, the light intensity that was required to evoke RGC responses remained unchanged after olfactory stimulation (A). By contrast, the application of D2 blockers did not inhibit olfactory stimulation-induced changes in RGC activity (B). Threshold RGC responses are indicated by arrows. The intensity of the light stimuli (at the bottom of the histograms) increased by 0.5 log-unit steps (from left to right), starting below or near threshold level (designated 0). SCH, SCH 23390; Sul, sulpiride.