FIGURE 4

Application of exogenous dopamine reduces ChR2‐induced fictive swimming activity. Fictive swimming was induced in spinalized Tg(vglut2a:Gal4ff)^nns20;Tg(UAS:ChR2(H134R)‐mCherry)^umn201 preparations by delivering 10 s‐long blue light stimuli at 3 min intervals. Dopamine (DA) treatment preparations were perfused with extracellular saline for 10 min, 10 µM DA was added to the perfusate for 10 min, followed by wash out of DA with saline. Control preparations were continuously perfused with extracellular saline. (a) Fictive swimming activity of an untreated control preparation (top) at t = 0 (baseline) and t = 18 min (+saline) and of a DA‐treatment preparation (bottom) at t = 0 (baseline) and t = 18 min (+10 µM DA). Blue lines represent continuous 10 s blue light stimuli. (b–e) Number of bursts produced during each 10 s stimulus (b), number of swimming episodes produced during each 10 s stimulus (c), mean burst duration (d), and mean burst frequency (e) of DA‐treatment (green) and untreated control (black) preparations. Horizontal green bar indicates time of 10 µM DA application. Shaded regions represent SD. Boxes indicate final baseline (Base), DA treatment (DA), and washout (Wash) stimuli that were compared between control (plots also shown in Figure 2) and DA‐treatment groups. Asterisks indicate significant differences between groups.