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Behavioral repertoire of larval zebrafish: Baseline activity and response to drug treatment.
Citation:
PADILLA, S. J., R. C. MACPHAIL, J. Brooks, T. Irons, D. L. HUNTER, J. COWDEN, AND B. K. PADNOS. Behavioral repertoire of larval zebrafish: Baseline activity and response to drug treatment. Presented at Fourth Aquatic Models of Human Disease Conference, Durham, NC, January 31 - February 03, 2008.
Impact/Purpose:
To support criteria for MYP
Description:
As part of the EPA’s effort to develop an in vivo, vertebrate screen for toxic chemicals, we have begun to characterize basic behaviors of 6-day post-fertilization (dpf) zebrafish (Danio rerio) larvae in a microtiter plate format. Our main goal is to develop a method for rapidly assessing abnormal behavior in larval zebrafish. Larvae were individually reared and tested in 96-well microtiter plates; animals were kept at 26C using a 14:10 light:dark cycle with lights on at 0830 hr. A video tracking system and attendant software were used to record locomotor activity (measured as total distance traveled) under two different lighting conditions: light (visible light) and dark (infrared light). When place in constant dark for 50 min, zebrafish larvae showed an initial peak in activity followed by minimal baseline activity thereafter. When placed in constant light, larvae showed the reverse pattern: an initial depression of activity followed by a much higher baseline level. Interestingly, the pattern of larval activity under alternating lighting conditions (10 min epochs of each lighting condition) showed a paradoxical pattern, with activity in the light markedly depressed and activity in the dark much higher than even the baseline activity in constant light. Moreover, control 6 dpf larvae acutely exposed to ethanol or d-amphetamine show changes in activity similar to a response to these same drugs in higher vertebrates. Developmental exposure to prototypic neurotoxic compounds (e.g., ethanol, cadmium or valproate) altered activity in a dose-related manner during the dark epochs of alternating light:dark periods, with lesser effect during the light periods. We conclude that even very young zebrafish possess a rich behavioral repertoire, especially if that activity is observed for relatively long periods of time (up to 1 hour), and if that activity is observed in both dark and light conditions. Furthermore, this activity is perturbed by developmental exposure to neurotoxic compounds. This is an abstract of a proposed presentation and does not reflect Agency policy. T.D. Irons is supported by the NIH NIGMS Initiative for Maximizing Student Diversity.