Figure 5

Figure 5

Effects of optogenetic activation of Hcrt neurons on alcohol-related behaviors, including locomotor activity and anxiety, in transgenic Hcrt:ChR2-EYFP⁵⁴ larval zebrafish (6 dpf). (a) Bar graph shows that optogenetic activation of Hcrt neurons by blue-light compared to red-light exposure increases locomotor activity in an open-field environment of a 12-well plate, as indicated by increased distance traveled (cm) during a 20-min test. (b) Bar graphs show that blue-light compared to red-light exposure increases thigmotaxis, an anxiety-like behavior, shown by increased percent time spent in the perimeter (cm) and increased number of entries into the perimeter of an open-field environment of a 12-well plate during a 20-min test. Representative activity traces shown in red illustrate the activity of a red- and blue-light-exposed zebrafish during the locomotor and thigmotaxis tests, with the white circular outlines illustrating the perimeter zone. (c) Bar graphs show that blue-light compared to red-light exposure, while having no effect on percent time spent in the light zone, increases the number of entries to the light zone during a 20-min light–dark preference test. Representative activity traces shown in red illustrate the activity of a zebrafish exposed to a red or blue light during the light–dark preference test, with the light zone shown on the left half and the dark zone shown on the right half of the well. Under visible light conditions, the dark zone is black in color. Results are shown as means ± standard errors. *p < 0.05, ***p < 0.001. hpf hours post fertilization, dpf days post fertilization.