Abstracts / Toxicology Letters 221S (2013) S31–S56 S45 as a readout of drug-induced neuronal activity.By mapping the neuronal substrates that change activity in response to sleep- and wake-inducing drugs, we hope to identify critical zebrafish sleep circuits. The function of these circuits in zebrafish sleep can then be dissected by traditional genetics or with optogenetic techniques. http://dx.doi.org/10.1016/j.toxlet.2013.06.161 W11-3 The utility of the zebrafish for drug safety assessment: an industry perspective Matthew J. Winter, Jonathon Ball, Alex Goonesinghe, Malcolm Hetheridge AstraZeneca, Safety, Health & Environment, Brixham, Devon, UK Recently the zebrafish has emerged as a credible, 3Rs- friendly,non-mammalian model for human drug safety assessment. In particular, the embryolarval form facilitates the use of low amounts of test compound in a microplate; attributes that allow development of higher throughput assays for use in frontloading (i.e. conducting earlier) functional drug safety assessment. The range of safety assessment disciplines for which promis- ing zebrafish based assays have been developed/proposed is wide: from developmental toxicity to cardiovascular function; and from ototoxicity to behavioral-based assays addressing adverse effects such as seizure and abuse liability. In our experience, however, relatively few validated assays are utilized routinely within phar- maceutical company safety assessment screening cascades. Here,using our own experiences and examples from the liter- ature, we explore the reasons for the apparent underutilization of this promising model by the pharmaceutical industry, within the context of the industry expectations for new models. Topics for discussion include: expected prediction of (pre)clinical out- come;desired levels of throughput and compound requirements; expected levels of automation; and the recurrent issues of rela- tive exposure concentrations, therapeutic versus assay effect levels, metabolic capabilityand clinical relevance. In addition, we highlight applications that appear particularly promising, for example gaps in current safety screening strategies that could be filled using this model. The overall aim is to pro- vide the audience witha better understanding of what is expected of a zebrafishmodel/assay before it is suitable for application in an industrial setting, with the ultimate aim of aiding thegreater exploitation of this highly promising model. http://dx.doi.org/10.1016/j.toxlet.2013.06.162 W11-4 Predicting drug-induced hepatotoxicity in zebrafish larvae N. Mesens 1 , A. Crawford 2 , A. Menke 3 , F. Van Goethem 1 , C. Esguerra 2 , A. Wolterbeek 3 , P. De Witte 2 , J. Van Gompel 1 1 Drug Safety Sciences, Janssen Pharmaceutical Companies of Johnson&Johnson, Beerse, Belgium, 2 Laboratory of Pharmaceutical and Biological Sciences, Katholic University of Leuven, Leuven, Belgium, 3 TNO Triskelion bv., Zeist, The Netherlands Zebrafish larvae represent an attractive lower animal model to fill the gap between high throughput in vitro cellular assays and conventional preclinical animal testing. The model may, in partic- ular, be useful in predicting human liver toxicity.Drug-induced liver injury (DILI) is poorly predicted by single- cell- based assays, likely- due to the lack of physiological integrations with other cells within the liver. The whole liver found in the zebrafish could provide added value in a screening strategy for DILI. The aim of this study was to set up an assay for assessing DILI in zebrafish larvaeby assessing the expression of a liver specific pro- teinin the larval liver. Hereto, LFABP10 was chosen as a marker since tissue- specific fatty acid binding proteins were recently suggested as plasma markers for tissue injury (Pelsers et al., 2005). In addition, investigating proteomic biomarkers during hepatotoxicity in rats showed that LFABP proteins were diminished after acetaminophen exposure; suggesting downregulation during acute hepatocellular necrosis (Yamamoto et al., 2006). The effect of reference compounds on fabp10 expression was then investigated. Compounds were selected to induce the major- ity of hepatotoxic phenotypes in humans (cholestasis, steatosis and necrosis) with knowninsults such as inhibition of the bile salt export pump, mitochondrial toxicity and reactive metabolite for- mation. Hepatotoxic compounds were identified by asignificant change inthe expression of the liver-specific protein fabp10. Differ- ent expression patterns were observed and compared with the histopathological changes in the liver, both in adults and zebrafish larvae. Whole genome micro-array analysis was included to eluci- date the mechanisms of DILI. Reference Pelsers, M.M., Hermens, W.T., Glatz, J.F., 2005. Fatty acid-binding proteins as plasma markers of tissue injury. Clin Chim Acta. 352 (Feb (1-2)), 15–35. Yamamoto, T., Kikkawa, R., Yamada, H., Horii, I., 2006. Investigation of proteomic biomarkers in in vivo hepatotoxicity study of rat liver: toxicity differentiation in hepatotoxicants. J Toxicol Sci. 31 (Feb (1)), 49–60. http://dx.doi.org/10.1016/j.toxlet.2013.06.163 W11-5 New approach to a predictive toxicity evaluation with a zebrafish assay Ainhoa Alzualde BBD BioPhenix S.L., San Sebastián–Donostia, Spain Toxicological screening is important for the development of new drugs and for the extension of the therapeutic potential of existing molecules. As behavior reflects integration of the vari- ous functional components of the nervous system alterations in behaviour could be indicative of toxicity. Changes in behaviour could be also observed due to indirect effects of drugs on other physiological systems. Zebrafish has a high genetic homology with humans and an important parallelism in organogenesis and functional mechanisms. Its small size, rapid development, high reproducibility and transparency make zebrafish an ideal model for screening large number of compounds. Here we present an assay based on locomotor activity evaluation of zebrafish larvae com- plemented with a general morphological screening. Biobide has validated this assay in zebrafish with several compounds. Larvae were treated with toxic, neuroactive and innocuous compounds during 2 days and their locomotor activity was evaluated at 6dpf under two light-dark cycles. Afterwards, a general morphologi- cal screening was carried out. Preliminary results indicate that zebrafish embryos show locomotorbehavior and/or morphological alterations in response to drug treatments allowing us to detect potential toxicity of compounds. Zebrafish are a good model to be used as a complementary to in vivo models in the Drug Discovery