FIG. 7.

Quantification of brain dopamine level with high-performance liquid chromatography (HPLC). Chromatogram of standard dopamine showing a retention time between 3.196 and 3.442 min (A) and chromatogram for Drosophila head tissue extract, showing a peak during the observed time window for standard dopamine (B) (peak for dopamine is pointed with an arrow in both the panels). Peaks can be seen (at 5 min and 7.5 min) much away from retention time window observed for standard dopamine that amount to artifact.