Levels of monoaminergic neurochemicals in the head and trunk of zebrafish larvae. (A) Distribution in the head and the trunk of control larvae 8 days post-fertilization (dpf); (B) Distribution in the head and the trunk of 8 dpf larvae exposed for 24 h to 5 µM deprenyl, a monoamine-oxidase inhibitor, in the water. Data were normalized by protein content (n = 8 pools) * p < 0.05, *** p < 0.001; Student’s t-test; Data from 2 independent experiments.

Distribution of monoaminergic neurochemicals between the head and trunk of zebrafish larvae exposed to 5 µM deprenyl for 24 h. (A) Concentration of monoaminergic neurochemicals in the head and trunk of larvae exposed to deprenyl, expressed as a percentage of the control values; (B) Ratio of head/trunk for the ten selected monoaminergic neurochemicals in control and deprenyl-treated zebrafish larvae. Data was normalized by protein content. Student’s t-test (n = 8 pools); * p < 0.05, ** p < 0.01, *** p < 0.001; Data from 2 independent experiments.

Profile of monoaminergic neurochemicals after deprenyl treatment: head vs. whole body. Concentrations are presented as percentage of the control values. (A) Data normalized by protein content; (B) Data normalized by larva. Student’s t-test (n = 8 pools); ns: non-significant, * p < 0.05, ** p < 0.01, *** p < 0.001; Data from 2 independent experiments.

Analysis of the variability of the determination of neurochemicals in the head and the whole body of control larvae. Coefficient of variation was used for determining the variability of the concentrations of the monoaminergic neurochemicals determined in the head and the whole body.