Fig 1.
Stress-related behaviour assessed by thigmotaxis in zebrafish larvae A,B) 9dpf, C,D) 10dpf, E,F) 23dpf juveniles. G,H) Effect of diazepam on larval stress-reactivity assessed by thigmotaxis. Time course of average time spent each minute at the edge of the apparatus (A, C, E), overall average time spent per minute at the edge of the apparatus (B, D, F). (A-D) Developmental ethanol exposure decreased thigmotaxis at both 9dpf (A,B: F 2,105 = 4.76, P<0.05) and 10dpf (C,D: F 2, 285 = 6.69, P<0.05), with the greatest difference between 20mM ethanol treatment and the control. Siblings of the same animals were raised for another 2 weeks and tested as 23 dpf juveniles (E,F). These juveniles exhibited a similar thigmotaxis response as at 9dpf, with decreased thigmotaxis in ethanol treated animals compared to controls (F 2,146 = 2.93, P<0.05). (G-H) Larvae acutely treated with diazepam for 6 minutes exhibited significantly reduced time spent at the edges of the wells compared to controls (F 1, 259 = 5.47, P<0.01). There were no significant differences in distance travelled. Post-hoc t-test: *** P<0.001, ** P<0.01.
Fig 2.
Stress-reactivity of 6-month old zebrafish as assessed by thigmotaxis.
A) Time course of average time spent per minute at the edge of the apparatus, B) overall average time spent per minute at the edge of the apparatus, C) distance travelled during thigmotaxis, D) Effect of diazepam on adult zebrafish stress-reactivity assessed by thigmotaxis. A,B) Adult zebrafish that had been experimentally exposed to ethanol spent decreased time at the edge of the tank, (F 2, 127 = 3.09, P<0.05). There were no significant differences in distance travelled (C). Adults acutely exposed to diazepam exhibited reduced time spent at the edges of the tanks compared to controls (F 1, 4.98 = 5.44, P<0.001) (D). Post-hoc t-test, * P<0.05.
Fig 3.
Stress-reactivity measured by novel tank diving in 6-month old adult zebrafish.
A) Time course of average time spent per minute at the bottom of the tank, B) overall average time spent per minute at the bottom of the tank each minute, C) mean distance travelled per minute during novel tank diving. D) Effect of diazepam on zebrafish stress-reactivity assessed by novel tank diving. A,B. Zebrafish that had been developmentally exposed to ethanol showed reduced bottom dwelling (F 2, 682 = 3.47, P<0.05). There were no significant differences in distance travelled (C). D. Diazepam also significantly reduced time spent by adults at the bottom of the tanks compared to controls (F 1, 408 = 5.45, P<0.001). Post hoc t-test, *** P<0.001.
Fig 4.
Stress-reactivity measured by scototaxis in 6-month old adult zebrafish A) Time course of average time spent at the bright side of the apparatus and B) overall average time spent at the bright side of the apparatus.
Adult zebrafish that had been developmentally exposed to ethanol spent more time on the bright side of the tank (F 2, 31 = 3.85, P<0.05). Post hoc t-test, ** P<0.01, * P<0.05.