Figure 1

Motor response is strongly impaired by acrylamide (ACR) in zebrafish larvae. (a) Locomotor activity of 8 days post-fertilization zebrafish larvae control (n = 78) and exposed to 0.5 mM ACR (n = 79) and 1 mM ACR (n = 77) during a 20 min dark period followed by a 10 min light period and then a second cycle of 20 min of darkness. Data from 3 independent experiments. (b) Basal locomotor activity (BLA), defined as the distance moved by the larvae during the first period of 20 min in the dark, was significantly reduced by ACR. Statistical analysis performed using one-way ANOVA with Dunnett’s multiple comparison test;; *P < 0.05, ***P < 0.00001; Results represent mean ± sem. (c) 1 mM ACR, but not 0.5 mM ACR, induced a period of hyperactivity in the dark to light transition (the difference in activity between the 2 first min with light and the last 2 min of the first dark period is represented). Statistical analysis performed using one-way ANOVA with Dunnett’s multiple comparison test; ***P < 0.00001; Results represent mean ± sem. (d) Visual motor response (VMR), the hyperactivity period evoked by a sudden reduction in light intensity, is strongly reduced in larvae exposed to 0.5 and 1 mM ACR. Statistical analysis performed using one-way ANOVA with Dunnett’s multiple comparison test; ***P < 0.00001; Results represent mean ± sem. (e) Larvae exhibiting a total abolition of the VMR after 1 mM ACR exposure exhibit a significant reduction in the acoustic/vibrational motor response evoked by a solenoid at four different intensities. Statistical analysis using Student’s t-test, *P < 0.05, ***P < 0.001; Data from 20 control and 22 ACR-treated larva from 5 independent experiments); Results represent mean ± sem. (f,g) Kinematic of the touch-evoked escape response is altered in zebrafish larvae exposed to 1 mM acrylamide. Representative kinematic traces of the touch-evoked escape response of control (f) and ACR-treated (g) larvae. For each condition eight representative traces are shown from the first 140 ms of the escape response. Each trace is from a different larvae. The curvature of the body is represented in degrees, with 0 indicating straight body.