Impairment of motor but not anxiety-like behavior caused by the increase of dopamine during development is sustained in zebrafish larvae at later stages.

In this study, we set out to determine whether these behavioral alterations were sustained in larvae at older stages (7 and 14 dpf). To test this hypothesis, we chronically treated zebrafish larvae from 3 to 5 dpf with DA. After washing the drug, we recorded and analyzed the first 5 minutes and 30 minutes of the motor behavior of 5 dpf, 7 dpf and 14 dpf subjects. We analyzed mobile episodes, distance travelled, time mobile, distance travelled per mobile episode, time in movement per mobile episode and distance travelled per time mobile. We showed, once again, that an increase of DA during the 3 to 5 dpf developmental window reduces the number of movement episodes initiated by 5 dpf larvae. We also detected a decrease of other motor behavior parameters in 5 dpf DA treated larvae. We observed that these alterations are sustained in the 7 dpf larvae. However, we did not see these general locomotor alterations in the 14 dpf larvae. On the other hand, we detected a decrease of distance travelled and an increase of time of locomotion per episode in the first 5 minutes of behavioral analyses in 14 dpf DA treated larvae. To test if the alterations in the first 5 minutes were due to anxiety-like behavior, we used a light/dark preference paradigm. We recorded 5dpf, 7dpf and 14dpf larvae for 5 minutes and analyzed time of freezing, preference for light or dark, number of entries to the dark, percentage of time in the light. We observed that 5dpf larvae treated with DA showed more freezi...
Source: International Journal of Developmental Neuroscience - Category: Neuroscience Authors: Tags: Int J Dev Neurosci Source Type: research